Customer Care :
Energy Solutions (Private) Limited – ESL, as a part of its Corporate Social Responsibility (CSR), operates a full- fledged Customer Care Centre. The Customer Care Centre makes available informative articles / literature and handbooks alongside free of cost Training Sessions on operational matters, quality control, continuous improvement and HSSE for its own employees and those of the corporate society, at large. ESL top management stands committed to make these a cornerstone of its business.
The training sessions are conducted at both our own or the Customer’s premises as per the customer’s requirements.
The information on the website is periodically updated and new articles are uploaded from time to time.
Please reach us at www.eslpk.com/customer-care and keep watching for what is new.
Please note that the articles / literature listed below are for the purpose of training and awareness. No attempt should be made to use them as a substitute for expert technical help.
For an in-depth discussion(s) and customer specific solution(s), please contact us at:
customercare@eslpk.com or support@eslpk.com
Thanks and Best Regards,
ESL Customer Care
Energy Solutions Private Limited (ESL)
Customer Care Articles – English :
Dear Customer:
- We are truly indebted to our long list of customers, which includes Coca Cola, Shell Pakistan, Allied Bank, Shaukat Khanum Hospital, Dow University of Health & Sciences, Mobilink, Pakistan Tobacco Company (BAT), Container Terminals, Shahtaj Textile, University of Engineering & Technology Lahore, Atlas Group, ABL, Pakistan Refinery, etc. These customers have motivated us to invest heavily towards the improvement of our ways of working.This has led us to focus more intensely on safety, quality and training. We believe that only through continuous improvement (training), we can manage to work safely and deliver the right quality, too.
- ESL has compiled a range of short articles for the benefit of its customers, employees, suppliers and society, at large. We will continue to update the information and add more from time to time. Please reach us at www.eslpk.com/customer-care/ and keep watching for what is new.
- Please note that these articles are for the purpose of training and education. No attempt should be made to use them as a substitute for expert technical help.
- For an in-depth discussion(s) and customer specific solution(s), please contact us at: customercare@eslpk.com or support@eslpk.com.
Thanks and best regards,
ESL Customer Care
Energy Solutions Private Limited (ESL)
THE SAFETY CULTURE WE SHOULD ADOPT?
- The Safety Culture We Should Adopt? 1. A Safety Culture can be thought of as a set of values, beliefs, perceptions and behaviors that an organization espouses with respect to safety habits while conducting its business.
- Every organization has a safety culture, intentional or not so intentional. The important thing is:
a.Whether we want a particular safety culture and
b.What do we do to create it?
c.Whether we set ourselves goals to achieve it?
- THE SAFETY CULTURE WE ADOPT MUST HAVE THE FOLLOWING FEATURES:
a.Communication is open at all levels of the organization and feedback is considered vital to improving safety processes.
b. Individuals at all levels focus on what should be done to prevent injuries or illnesses.
c. There is a commitment to safety as much as it is for the business.
d. People and their safety and health are considered important.
e. The focus is on the people, and the contribution to the bottom line is a natural outcome.
f. All personnel, especially senior managers, lead by example and demonstrate their commitment to safety by following all safety processes and procedures, just as they want their employees to do.
g. Good habits are practiced both at work and away.
- THE SAFETY CULTURE WE MUST AVOID HAS THE FOLLOWING FEATURES:
a. Communication is not open at all levels; employees’ feedback is considered neither important nor encouraged.
b. Safety rules are used as a stick to discipline and penalize.
c. Management may not follow safety rules (for example, not wearing seat belts, not abstaining from smoking in nonsmoking areas, not using Personal Protective Equipment (PPEs), using cell phone while driving, etc.).
d. Focus on business results outweighs focus on safety.
e. Safety is sermonized to create good safety records and documentation.
f. Safety shutter is pulled down after office hours.
WHY SHOULD WE INVEST IN AVOIDING AN ACCIDENT?
Every accident has a cost associated with it, which is always far higher than the investment made in avoiding it. That is why; all necessary measures must be adopted to prevent an accident both at work and away.
The costs that are involved because of an accident are both direct and indirect. The employee who loses his life, or is injured is the biggest sufferer. The organization also does not go unhurt. The costs associated with an accident are always more than just dollars and cents.
- Direct Costs for the Employee
a. Lost wages and overtime
b. Doctor & hospital bills
- Indirect Costs for the Employee
a. Physical pain and suffering
b. Mental agony
c. Lost time with family and friends
d. Loss of productivity on and off the job
e. Relationship strain
- Direct Costs for the Employer
a. Medical bills and workers’ compensation claims
b. Legal costs
c. Insurance costs
d. Property damage costs
e. Wages being paid for an ideal / injured worker
- Indirect Costs for the Employer
a. Loss of a valuable employee
b. Loss of productivity
c. Replacement cost in terms of rehiring and retraining
d. Equipment repair / replacement cost
e. Police inquiries and / or court / katcheries
(a) Decrease in employee morale over the loss of an employee
(b) Fear amongst other employees, etc.
WAKE UP CALL FOR LEADERS!
- Various safety journals / periodicals, call attention to the role of leaders in HSSE:
- “Attitudes to health and safety are determined by the bosses, not the organization’s size”.
- “Health and safety is a key to success. Bosses who do not show direction in this area are failing in their duty as leaders and are not fulfilling their moral obligation, as a result damaging their own hard built organization”.
- “An organization will never be able to achieve the highest standards of health and safety management without the active involvement of the bosses”.
- “Health & Safety drive without involvement of boss is like a rudderless ship”.
- “Health and safety is a fundamental part of business. Companies need someone with passion and energy to ensure it stays at the core of the organization. This someone has to be from amongst the bosses”.
WHAT BOSSES MUST DO
Provide strong and active leadership for HSSE. It requires:
- Showing commitment to safety;
- Establishing effective ‘downward’ communication systems and safety forums for gaining participation of all;
WAKE UP CALL FOR LEADERS!
- Treating health and safety management as important as business decisions.
Gain worker involvement. It requires:
- Engaging the workforce in the promotion and achievement of safe and healthy conditions;
- Effective ‘upward’ communication;
- Providing quality training.
Assessment and review requires:
- Identifying and managing health and safety risks;
- Accessing (and following) competent advice;
- Monitoring, reporting & reviewing performance
WHEN THE BOSS LIVES UP TO HIS RESPONSIBILITIES AS HSSE LEADER
When HSSE is not seen as a regulatory burden: it offers significant opportunities.
Benefits can include:
- reduced costs and reduced risks
- employees’ absence and turnover rates are lower,
- accidents are fewer,
- the threat of legal action is lessened;
- improved standing among suppliers and partners;
- a better reputation as a responsible corporate citizen among investors, customers and communities;
- increased productivity – employees are healthier, happier and better motivated secure
LEGAL RESPONSIBILITIES OF THE BOSS AS AN EMPLOYER
Health and safety law, in developed world, states that organizations must:
- provide a “Safety Manual” – written health and safety policy (if they employ five or more people);
- assess risks to employees, customers, partners and any other people who could be affected by their activities;
- arrange for the effective planning, organization, control, monitoring and review of preventive and protective measures;
- ensure they have access to competent health and safety advice;
- Consult employees about their risks at work and current preventive and protective measures.
Failure to comply with these requirements can have serious consequences – for both organizations and individuals. Sanctions include fines, imprisonment and disqualification.
ROADMAP FOR THE BOSS
- PLANNING PHASE
GOOD PRACTICE
- Health and safety should appear regularly on the agenda of their meetings.
- One of the board members should be named as the health and safety ‘champion’.
- The presence on the board of a health and safety director can be a strong signal that the HSSE is of strategic importance.
- DELIVERING HEALTH AND SAFETY
GOOD PRACTICE
- Be existent and seen on the ‘shop floor’, following all safety measures yourself and addressing any breaches immediately.
- Consider health and safety when deciding senior management appointments and / or promotions.
- Enforce procurement standards for goods, equipment and services to help prevent the introduction of expensive health and safety hazards.
- Assess the health and safety arrangements of partners, key suppliers and contractors – a safety week may serve as an apt reminder.
- Identify and address the key issues and guard against time and effort being wasted on trivial risks and unnecessary bureaucracy.
- Provide health and safety training to some or all of the top management to promote understanding and knowledge of the key issues in your organization.
- Support worker involvement in health and safety.
- MONITORING HEALTH AND SAFETY
GOOD PRACTICE
- Effectively monitor sickness absence and workplace health as a tool to ascertain underlying problems that could seriously damage performance or result in accidents and long-term illness.
- The collection of workplace health and safety data can allow the boss to benchmark the organization’s performance against others in its sector.
- Appraisals of senior managers can include an assessment of their contribution to health and safety performance.
- As a boss ask for regular reports on the health and safety performance and actions of contractors.
- Win greater support for health and safety by involving workers in monitoring.
- REVIEWING HEALTH AND SAFETY
GOOD PRACTICE
- Join the bandwagon of reputed organizations in which performance on health and safety is increasingly being recorded in annual reports to stakeholders.
- Increase ‘shop floor’ visits to gather information for the formal review.
- Celebrate, recognize and reward (R&R) good health and safety performance.
WHEN LEADERSHIP FALLS SHORT
- In Sri Lanka, following the fatal injury of an employee maintaining machinery at a recycling firm employing approximately 30 people, a company director received a 12-month custodial sentence for manslaughter. LOTO was not followed. ‘Evidence showed that the director chose not to follow the advice of his health and safety advisor and instead adopted a complacent attitude, allowing the standards in his business to fall.’
- In Bangladesh, the managing director of a manufacturing company with around 100 workers was sentenced to 12 months’ imprisonment for manslaughter following the death of an employee who became caught in unguarded machinery. The judge made clear that whether the managing director was aware of the situation was not the issue: he should have known as this has always been known potential hazard.
- In India, a company employed ten, mostly young, temporary workers; they were not trained or equipped to safely remove the asbestos, nor warned of its risk. Its officers were fined a fortune, disqualified from holding any directorship for two years and ordered to pay hefty costs of prosecuting Court.
BOSSES BEWARE!
It can happen in India, Bangladesh and Sri Lanka. It happens in Pakistan too day-in-and-day-out. Bosses beware!!
SHELL, SKM, JCI AND LCSC CALLS YOUR ATTENTION TO WAKE UP BEFORE IT IS TOO LATE.
SAFETY CONCERNS WHILE HANDLING DIESEL
There are three primary concerns associated with diesel fuel:
- Flammability:
Diesel is not as flammable as gasoline and others but it can catch fire and can be very difficult to extinguish. Do not smoke around diesel fuel.
- Skin Exposure:
Diesel fuel can be absorbed through the skin very easily. It can cause skin irritation, redness and even burns. If the diesel is not cleaned off, it will be adsorbed into the skin and cause symptoms identical to inhalation.
- Inhalation:
If diesel vapors are inhaled, it can cause dizziness, nausea and increased blood pressure, among other symptoms.
How to limit harmful effects of diesel?
- When fueling diesel powered vehicles or machinery, do so in a well-ventilated area.
- If machines especially generators are used indoors or in enclosed spaces, extra ventilation should be provided to remove diesel exhaust. Make sure exhaust of diesel generators is emitted away from the power plant and away from people.
- Wear appropriate gloves when working with diesel.
- Do not use vinyl or butyl rubber gloves with diesel, as they offer no protection.
- Maintain diesel vehicles / generators well and regularly keep an eye on exhaust / emission(s).
SAFETY CONSIDERATIONS WHILE HANDLING GENERATORS
Safety Considerations
- General Hazards
- Installation, repair and maintenance should always be in accordance with the manufacturer’s instructions and recommendations.
- Exhaust fumes emitted by generator sets contain poisonous gases like carbon monoxide that can be life threatening and result in death. Exhaust systems must be properly installed, adequate ventilation must be provided to ensure unobstructed flow of cooling and ventilating air, and emissions must be directed away from inhabited zones.
- The area around the generator must be clean and free of clutter and any combustible material that can be hazardous.
- The equipment must be regularly inspected and defective or damaged parts must be replaced in a timely manner.
- It is essential that the operating personnel remains alert at all times while working with the generator.
- The unit should not be opened or dismantled while it is functioning. Moving or hot parts should not be tampered with.
- Battery cables should be disconnected before proceeding to work on the generator to eliminate any possibility of an accidental start-up.
- Electrical Hazards
- All power voltage supplies should be turned off at the source while installing or servicing the generator.
- All electrical connections, such as wires, cables and terminals must be properly insulated and covered, and should not be touched with bare hands or while in contact with water. This is essential to prevent the occurrence of an electric shock.
- The frame of the generator and any external conducting parts should have proper grounding or earth wiring. This should never be disconnected.
- Wiring, cable and cord sets must be of the recommended capacity.
- Fire and Explosion Hazards
- Smoking in the vicinity of the equipment can be fatal.
- Fuel or oil spills around the generator, leakages from the unit’s fuel system and fuel supply lines and presence of combustible materials around the generator will pose a risk of explosion.
- A fire extinguisher should be readily available. Use of extinguishers that operate on carbon tetra-chloride is strictly prohibited since the fumes are toxic and can deteriorate the insulation on the wiring of generators.
FIVE S APPROACH TO OUR HSSE COMMITMENT
SEIRI (Sort)
- A clean place is a safe place.
- Cleaning starts with sorting.
- Sort any given population of items, activities, behaviors, attitudes and even entities, etc.
- Separate important from non-important; useful from wasteful; critical from non-critical.
- Classify into “Dos and Don’ts”.
- Dispose of and discard the wasteful, unwanted items / activities / attitudes / behaviors.
- Retain the important, useful and critical items / activities / entities / behaviors / attitudes.
First Step: Safety starts from cleaning
Cleaning starts from sorting
Sorting separates crucial from the clutter
SEITON (Set in Order)
- Assign priorities to the chosen items.
- Do a 80 / 20.
- Do a Pareto analysis.
- Rank critical items in accordance of their relative importance.
- Separate few “vitals” from many “trivial”.
- Assign a place to everything and assign everything to its designated place.
Second Step: Assign a place for everything – and put everything in its place.
Put the action where the money is.
SEISO (Shine)
- Make “Continuous Improvement” in HSSE a way of life.
- Make it a 24 x 7 affair, round the year, every year, year after year.
- Don’t allow switch “off” and “on” and “fits and start” mentality.
- Put it under your skins, in your blood, in your DNA
- Check out before you step out
- Consider HSSE an unending journey instead of a race, which has an end-point.
- In a race there is a last lap which takes you to the victory, in HSSE every lap is a lap to victory
- Gradually raise the bar / Take small incremental steps.
- Even a small step is a big step.
- Build a hierarchy of personal commitments, top down and share / review.
- Learn from the achievers, support underperformers.
- Bring change by Involving technology, creating HSSE systems, improving mindsets / behavior patterns
Third Step: Shine to surpass previous best
SEIKETSU (Standardize)
- Ensure steps / actions to keep the shine.
- Establish standards.
- Develop checklists.
- Talk not, Tick.
- Use control charts, Poka Yoke
- Develop jigs and fixtures or their equivalent(s).
- Integrate with daily work management.
Fourth Step: Standardize to maintain consistency
and hold the gains.
SHITSUKE (Self Discipline)
- Create an environment through slogans, posters and other visuals
- Identify BIC performance and use benchmarking vis a vis BIC.
- Lead by example (Be a Mr. Marriott).
- Conduct audits to evaluate approach and results.
- Recognize and reward.
Fifth Step: Walk the talk: Do what you say
Action speaks louder than the words
SAFETY OF OUR GENERATORS AND OUR PERSONNEL
The following actions must be taken to ensure safety of people and our generators before we commence any work on them. Please also encourage relevant people to read ESL Safety Booklet in Urdu for better understanding of the subject.
Know Jobsite Hazards
To make employees aware of potential risks around the work area and help minimize or eliminate safety and health hazards e.g. Is the generator room airy? Is the exhaust properly vented? Etc.
Know Your Work Procedures
- To identify the best way of performing a job.
- To determine:
- Are you qualified to perform the work?
- Do you know what is Lockout / Tagout (LOTO), how to isolate the site from others and what are emergency procedures?
- Do you have the correct PPE for the job you are performing and is it in proper working condition?
- Do you have all of the necessary tooling and testing equipment? Is it calibrated and in proper working condition?
Know the Job Specific Project Work Plan (e.g. Gantt Chart)
- Identify all activities
- Define, describe and communicate the roles, responsibilities and location of each employee on the project. Who will do what?
Build a Communication Plan
- Make someone responsible for communication and everyone must understand that he / she has to follow the qualified, nominated person.
- The responsible person must ensure that it is safe prior to commencing work and that entire team understands system shut down, and re-start procedures.
Make Emergency Action Plan and Make it Known
- Make a plan and take steps to ensure the safety of your employees in the event of an emergency. The plan should include:
- Roles and responsibilities
- Threats, hazards and protective actions
- Means for locating family members in an emergency
- Emergency shutdown procedures, etc.
- Once the employees have received the appropriate training, conduct regular drills as a reminder and post the Action Plan in an area that allows easy visibility.
Build a Safety Training Culture
- Prepare a safety manual for the specific conditions found on your jobsite.
- Make checklists for recurring / recurrent jobs and when appropriate make use of local language.
- Ensure equipment, tools and materials are being used for their intended purpose.
- Always review the manufacturer’s Operation and Maintenance Manual before putting a machine to work.
- Train employees on:
- Keeping track of others in the work zone and letting them know where you are at all times.
- Establishing eye contact before entering a work zone.
- Creating two-way communications before entering a work zone.
- Informing coworkers when leaving a work zone.
- Receive emergency first aid training. If it is not applicable to you to be trained in these areas, make sure you know who is qualified to perform these tasks on your jobsite.
ACTIONS WHICH MUST PRECEDE START OF WORK ON GENERATOR
Don’t start the work on generator without the following.
- Disconnect all energy sources before working on power generation equipment.
- Bring generators in a safe, de-energized, zero-stored-energy state.
- Do not trust “OFF” and “EMERGENCY STOP” push buttons on software and microprocessors as safety devices.
- Do not trust that a switch is open while in the “OFF” position. Always test and try operating the product prior to servicing as an alternative to ensuring the product is in a zero-stored-energy state.
- All AC and DC circuits entering and leaving the product shall be opened and secured with an appropriate LOTO device, thus electrically isolating the equipment to be serviced.
- Engine generator set packages shall have the battery cables removed from the batteries at the battery ends, and the battery cable ends shall be secured with an appropriate LOTO device.
- Gas and diesel fuel lines and air start lines shall be closed, and the valves shall be secured with an appropriate LOTO device.
- Any fuel or air between the valve and the engine shall be drained or vented.
- Remember to remove power from all attachments such as battery chargers, jacket water heaters and generator space heaters.
- Make sure there is no stray voltage anywhere on the package and that all voltage sources are properly secured in the “OFF” or “OPEN” position with an appropriate LOTO device.
- Open the product’s output circuit breaker and secure it with an appropriate LOTO device to prevent an external source from energizing the product or starting a generator set package’s engine.
Ensure proper grounding
Ensure the product is always properly grounded and the conductive surfaces surrounding the work are also bonded to the product’s grounding system to prevent any difference in electrical potential between the conductive surfaces and hence any chance of electric shock or electrocution.
Connect your work with that of others
- With multiple jobs going on at a jobsite, it is important to be aware of the other job tasks and associated processes that are being performed near or around you. Always look for the following:
- Is there any work by others going on overhead?
- What potentially dangerous work environment changes are others making that could jeopardize your safety?
- What work environment changes are you making that could jeopardize the safety of others?
IMPORTANT – Generators and Distribution Systems Rated ABOVE 600 Volts:
Prior to working around exposed bus bars and load cable terminations, ensure all stored energy has been discharged from the generator windings, bus bars and cables. Medium and high voltage windings and cables store electrical energy that could cause death or personal injury. Wear proper PPEs and use properly rated tooling and equipment to discharge the windings, bus bars and cables.
CHECK OUT BEFORE YOU STEP OUT – TALK NOT TICK
- Are you mentally and physically prepared to safely complete the work on the generator or are you fatigued such that your injury risk level is elevated?
- Is there any moisture on your shoes and/or clothes?
- Are you wearing the proper Personal Protective Equipment (PPE)?
- Head protection
- Eye protection
- Hearing protection
- Face shields
- Gloves
- Steel toe or metatarsal boots
Checklists
- Check your work area:
- What is in it?
- What is above and around you?
- How hot or cold is it?
- Is it humid?
- Is it a combustible atmosphere (i.e. dust from coal/grain/sugar or hydrogen from leaky batteries)?
- What would happen if you created an arc or spark in your immediate work area?
- Are overhead conductors exposed and grounded surfaces exposed around you?
- Are you aware with the Scope of Work (SOW) to be performed on the generator?
- Have you informed the customer (responsible person) about your presence, nature of work and approximate duration?
- Do you satisfy yourself regarding quality of work by checking what has already been done?
- Do you make sure there will be no requirement for rework for an extended period of time?
DISCRETION IS BETTER THAN VALOR – LOCKOUT AND TAG OUT (LOTO)
- Lockout is the primary means of preventing the unplanned release of hazardous energy.
- For electrical workers, it often involves using a padlock to keep a switch in the “off” position. It may also be necessary to isolate the energy of moving parts, chemical reactions, etc., that can endanger lives. Lockout is a physical way to ensure that the energy source is de-energized, deactivated, or otherwise inoperable.
Lockout involves:
- identifying all energy sources that may affect the work and work area
- redirecting or stopping the energy from doing what it is normally intended to do
- physically preventing the accidental re-energizing of the system, and
- verifying zero energy.
- It is important to control all energy systems involved in the work. A piece of equipment may have an electrically-operated component as well as hydraulic or pneumatic parts. Failure to control each energy system could jeopardize the safety of workers involved. In addition, gravity, momentum, and stored energy can present unexpected hazards.
- Tags are an important part of a lockout. After attaching his or her personal lock, the worker attaches a tag to the lock. Tags are a means of communication. Tags are used to inform others that:
- The device is locked out,
- Who has locked it out, and
- Why?
- Tagged devices and systems must not be re-energized without the authority of those named on the tag.
Forms of energy
- When most people think of uncontrolled hazardous energy, they think of electricity. But electricians overseeing a lockout procedure need to consider a variety of energy sources. Here are the main types of energy.
- Electrical (electrical panels, generators, lighting systems, storage batteries, etc.)
- Mechanical—the energy of moving parts (flywheels, blades, fans, conveyor belts, etc.)
- Potential—stored energy that can be released during work. Examples of systems having potential energy include suspended loads, compressed air, coiled springs, chemical reactions, changing states (solid—liquid—gas), etc.
- Hydraulic (presses, cylinders, cranes, forklifts, etc.)
- Pneumatic (lines, compression tanks, etc.)
- Thermal (steam, hot water, fire, etc.)
- Chemical (flammable materials, corrosive substances, vapors, etc.)
As mentioned above, some equipment may involve more than one type of energy and pose unexpected hazards.
- A de-energized electrical system must be discharged by short circuit and phase to ground. A temporary ground cable must be attached to the system and remain in place until work is completed.
- Switches, power sources, pneumatics, hydraulics, computer-controlled sources, gravity-operated sources—all of these must be locked out by each worker involved and appropriately tagged.
Employers must have a lockout policy as part of their overall health and safety policy and program, with a clear objective of isolating (locking) and identifying (tagging) all energy sources before work begins.
The policy should also identify procedure to return to work after lock out.
LOCK OUT, TAG OUT – FLOW CHARTS
Specific lockout procedures will vary depending on the work and the processes which must be shut down. The following chart can help you develop specific procedures.
POWER GENERATION – FAQS (FREQUENTLY ASKED QUESTIONS)
Many of our existing customers and / or prospective buyers rely upon ESL to provide them with accurate and informative answers to their electrical, engine, and generator related questions. This results in numerous questions every day, some of which are as under:
- What is the difference between KVA and KW?
- What is a power factor?
- What is the difference between standby, continuous, and prime power ratings?
- If I am interested in a generator that is not the voltage I need, can the voltage be changed?
- What does an Automatic Transfer Switch do?
- Can a generator I am looking at parallel with one I already own?
- Can you convert a 60 Hz generator to 50 Hz?
- How do I determine what size Generator I need?
- What is bumpless transfer of power between Generator set and Utility?
- What is load management and demand management?
1. What is the difference between kW and kVA?
The primary difference between kW (kilowatt) and kVA (kilovolt-ampere) is the power factor. kW is the unit of real power and kVA is a unit of apparent power (or real power plus re-active power). The power factor, unless it is defined and known, is therefore an approximate value (typically 0.8), and the kVA value will always be higher than the value for kW.
In relation to industrial and commercial generators, kW is most commonly used when referring to generators in the United States, and a few other countries that use 60 Hz, while the majority of the rest of the world typically uses kVA as the primary value when referencing generator sets.
To expand on it a bit more, the kW rating is essentially the resulting power output a generator can supply based on the horsepower of an engine. kW is figured by the horsepower rating of the engine times 0.746. For example, if you have a 500-horsepower engine it has a kW rating of 373. The kilovolt-amperes (kVA) are the generator end capacity. Generator sets are usually shown with both ratings. To determine the kW and kVA ratio the formula below is used.
8 (pf) x 625 (kVA) = 500 kW
2. What is a power factor?
The power factor (pf) is typically defined as the ratio between kilowatts (kW) and kilovolt amps (kVA) that is drawn from an electrical load, as was discussed in the question above in more detail. It is determined by the generator’s connected load. The pf on the nameplate of a generator relates the kVA to the kW rating (see formula above). Generators with higher power factors more efficiently transfer energy to the connected load, while generators with a lower power factor are not as efficient and result in increased power costs. The standard power factor for a 3-phase generator is 0.8.
3. What is the difference between standby, continuous, and prime power ratings?
Standby power generators are most often used in emergency situations, such as during a power outage. It is ideal for applications that have another reliable continuous power source like utility power. Its recommend usage is most often only for the duration of a power outage and regular testing and maintenance.
Prime power ratings can be defined as having an “unlimited run time”, or essentially a generator that will be used as a primary power source and not just for standby or backup power. A prime power rated generator can supply power in a situation where there is no utility source, as is often the case in industrial applications like mining or oil & gas operations located in remote areas where the grid is not accessible.
Continuous power is similar to prime power but has a base load rating. It can supply power continuously to a constant load but does not have the ability to handle overload conditions or work as well with variable loads. The main difference between a prime and continuous rating is that prime power gensets are set to have maximum power available at a variable load for an unlimited number of hours, and they generally include a 10% or so overload capability for short durations.
4. If I am interested in a generator that is not the voltage I need, can the voltage be changed?
Generator ends are designed to be either reconnectable or non-reconnectable. If a generator is listed as reconnectable the voltage can be changed, consequently if it is non-reconnectable the voltage is not changeable. 12-lead reconnectable generator ends can be changed between three and single-phase voltages; however, keep in mind that a voltage change from three phase to single phase will decrease the power output of the machine. 10 lead reconnectable can be converted to three phase voltages but not single phase.
5. What does an Automatic Transfer Switch do?
An automatic transfer switch (ATS) transfers power from a standard source, like utility, to emergency power, such as a generator, when the standard source fails. An ATS senses the power interruption on the line and in turn signals the engine panel to start. When the standard source is restored to normal power the ATS transfers power back to the standard source and shuts the generator down. Automatic Transfer Switches are often used in high availability environments such as data centers, manufacturing plans, telecommunication networks and so forth.
6. Can a generator I am looking at parallel with one I already own?
Generator sets can be paralleled for either redundancy or capacity requirements. Paralleling generators allows you to electrically join them to combine their power output. Paralleling identical generators will not be problematic but some extensive thought should go into the overall design based on the primary purpose of your system. If you are trying to parallel unlike generators the design and installation can be more complex and you must keep in mind the effects of engine configuration, generator design, and regulator design, just to name a few. For paralleling of generators of any make, model and manufacturer, please contact ESL at customercare@eslpk.com
7. Can you convert a 60 Hz generator to 50 Hz?
In general, most commercial generators can be converted from 60 Hz to 50 Hz. The general rule of thumb is 60 Hz machines run at 1800 Rpm and 50 Hz generators run at 1500 Rpm. With most generators changing the frequency will only require turning down the at rpm’s the engine. In some cases, parts may have to be replaced or further modifications made. Larger machines or machines already set at low Rpm are different and should always be evaluated on a case to case basis. We prefer to have ESL experienced technicians look at each generator in detail in order to determine the feasibility and what all will be required.
8. How do I determine what size Generator I need?
Getting a generator that can handle all your power generation needs is one of the most critical aspects of the purchasing decision. Whether you are interested in prime or standby power, if your new generator can’t meet your specific requirements then it simply won’t be doing anyone any good because it can put undue stress on the unit and even damage some of the devices connected to it. Determining exactly what size of generator to get is often very difficult and involves a number of factors and considerations.
9. What is bumpless transfer of power between Generator(s) and Utility?
There are some highly critical applications such as data centers, process industries, hospitals and operation theatres, etc., where disruption in electrical power is neither affordable nor permissible. In such applications either large UPS systems or additional devices are used on either side of the power outage which ensure that gensets are momentarily paralleled with utility while switching load from the generator to the mains or vice versa. This ensures that operations are not hurt or hindered in any way and continuous, uninterrupted supply of power is available at all times. For more details and / or incorporation of bumpless transfer features in existing system, please consult ESL at customercare@eslpk.com.
10. What is load management and demand management?
Load management is prioritization of loads in order of their critical nature and adding /shedding of the same in view of the available power from the generator(s). Demand management is automatic switching ON / OFF gensets in view of the load that is to be supported at any given point of time. For more details and / or incorporation of load and demand management panels in existing system, please consult ESL at customercare@eslpk.com
RETURN TO SERVICE AFTER LOCK OUT
- The primary authorized individual assigned to de-energize and lock out equipment typically will be the one to return the equipment to service.
- Before lockout devices and locks are removed, the work area is inspected to check that all crew members associated with the lockout have been cleared from any hazardous areas and that all are accounted for.
- In addition, this person checks that all nonessential items have been removed and that the machine, equipment, or process is operationally intact.
- Personnel who could be affected by re-energization and equipment start-up must be notified by the person assigned to return the equipment to service.
- Once satisfied that the machine, equipment, or process is in a ready state, the primary authorized person removes any required locks, energy isolating devices, and tags.
- After lockout devices have been removed a formal startup procedure would be implemented, if applicable.
- If the equipment is to sit idle for a period of time, then a separate pre-start-up process should address the notification requirements.
LOCKOUT AND TAG REMOVAL WHEN AUTHORIZED PERSON IS ABSENT
- Occasionally a worker leaves the jobsite and leaves a lock in place intentionally or accidentally and may not be present when the equipment needs to be re-energized. Removing the lock may expose that worker and possibly others to danger.
- There must be a written procedure about how to remove lockout devices and tags safely. The procedure must cover locating the absent worker and obtaining permission to remove their lock.
- It must also cover how, if the worker cannot be found, to validate if it is safe to cut the lock from the lockout device and re-energize the system. The person removing the lock should be identified in the lockout documentation.
WHY USE DIESEL GENERATORS?
Why Diesel?
Thanks to the invention of Rudolph Diesel, the diesel engine has proved to be extremely efficient and cost effective. In Pakistan, Diesel fuel is priced moderately higher than gasoline but diesel has a higher energy density, i.e., more energy can be extracted from diesel as compared with the same volume of gasoline. Therefore, diesel engines in automobiles provide higher mileage, making it an obvious choice for heavy – duty transportation and equipment. Diesel is heavier and oilier compared with gasoline and has a boiling point higher than that of water.
How Does a Diesel Engine Work?
The distinction lies in the type of ignition. While gasoline engines operate on spark ignition, diesel engines employ compression-ignition for igniting the fuel. In the latter, air is drawn into the engine and subjected to high compression that heats it up. This results in a very high temperature in the engine, much higher than the temperature attained in a gasoline engine. At peak temperature and pressure, diesel that is let into the engine ignites on account of the extreme temperature.
Why is the compression ratio of diesel engine higher than gasoline engine?
In a diesel engine, air and the fuel are injected into the engine at different stages, as opposed to a gas engine where a mixture of air and gas are introduced. Fuel is injected into the diesel engine using an injector whereas in a gasoline engine, a carburetor is used for this purpose. In a gasoline engine, fuel and air are sent into the engine together, and then compressed. The air and fuel mixture limits fuel compression, and hence the overall efficiency. A diesel engine compresses only air, and the ratio can be much higher. A diesel engine compresses at the ratio of 14:1 up to 25:1, whereas in a gasoline engine the compression ratio is between 8:1 and 12:1. After combustion, the combustion by-products are removed from the engine through the exhaust. For starting during cold months extra heat is provided through ‘glow plugs’.
What are different versions of diesel engines?
Diesel engines can either be two cycle or four cycle and are chosen depending on mode of operation. Air-cooled and water-cooled engines are the variants to be chosen appropriately. It is preferable to use a liquid-cooled generator as it is quiet in operation and has evenly controlled temperature.
What are the advantages of a Diesel Engine?
The diesel engine is much more efficient and preferable as compared with gasoline engine due to the following reasons:
- Modern diesel engines have overcome disadvantages of earlier models of higher noise and maintenance costs. They are now quiet and require less maintenance as compared with gas engines of similar size.
- They are more rugged and reliable.
- There is no sparking as the fuel auto-ignites. The absence of spark plugs or spark wires lowers maintenance costs.
- Fuel cost per Kilowatt produced is thirty to fifty percent lower than that of gasoline engines.
- A 1500 rpm water cooled diesel unit operates for 12,000 to 30,000 hours before any major maintenance is necessary.
What are the Applications & Uses for Diesel Engines?
Diesel engines are commonly used as mechanical engines, power generators and in mobile drives. They find wide spread use in locomotives, construction equipment, automobiles, and countless industrial applications. Their realm extends to almost all industries and can be observed on a daily basis if you were to look under the hood of everything you pass by. Power generation for prime or standby backup power is the major application of today’s diesel generators.
Usage of diesel engines in Power Generators
Diesel powered generators, or electrical generator sets, are used in countless industrial and commercial establishments. The generators can be used for small loads, such as in homes, as well as for larger loads like industrial plants, hospitals, and commercial buildings. They can either be prime power sources or standby/back-up power sources. They are available in various specifications and sizes. Diesel generator sets rating 5-30KW are typically used in simple home and small office(s) applications. Industrial applications cover a wider spectrum of power ratings (from 30 kW to 6 Megawatts) and are used in numerous industries throughout the globe. For
Domestic use, single-phase power generators are sufficient. Three-phase power generators are primarily used for industrial purposes.
HOW DOES AN ALTERNATOR AND A VOLTAGE REGULATOR WORK?
How does an Alternator produce electricity?
The alternator is the part of the generator that produces the electrical output from the mechanical input supplied by the engine. It contains an assembly of stationary and moving parts encased in a housing. The components work together to cause relative movement between the magnetic and electric fields, which in turn generates electricity.
(a) Stator – This is the stationary component. It contains a set of electrical conductors wound in coils over an iron core.
(b) Rotor / Armature – This is the moving component that produces a rotating magnetic field in any one of the following three ways:
(i) By induction – These are known as brushless alternators and are usually used in large generators. An alternator that does not use brushes requires less maintenance and also produces cleaner power.
(ii) By permanent magnets – This is common in small alternator units.
(iii) By using an exciter – An exciter is a small source of direct current (DC) that energizes the rotor through an assembly of conducting slip rings and brushes.
The rotor generates a moving magnetic field around the stator, which induces a voltage difference between the windings of the stator.
This produces the alternating current (AC) output of the generator.
What is a Voltage Regulator and how does it function?
As the name implies, this component regulates the output voltage of the generator. The mechanism is described below against each component that plays a part in the cyclical process of voltage regulation.
- Voltage Regulator: Conversion of AC Voltage to DC Current – The voltage regulator takes up a small portion of the generator’s output of AC voltage and converts it into DC current. The voltage regulator then feeds this DC current to a set of secondary windings in the stator, known as exciter windings.
- Exciter Windings: Conversion of DC Current to AC Current – The exciter windings now function similar to the primary stator windings and generate a small AC current. The exciter windings are connected to units known as rotating rectifiers.
- Rotating Rectifiers: Conversion of AC Current to DC Current – These rectify the AC current generated by the exciter windings and convert it to DC current. This DC current is fed to the rotor / armature to create an electromagnetic field in addition to the rotating magnetic field of the rotor / armature.
- Rotor / Armature: Conversion of DC Current to AC Voltage – The rotor / armature now induces a larger AC voltage across the windings of the stator, which the generator now produces as a larger output AC voltage.
This cycle continues until the generator begins to produce output voltage equivalent to its full operating capacity. As the output of the generator increases, the voltage regulator produces less DC current. Once the generator reaches full operating capacity, the voltage regulator attains a state of equilibrium and produces just enough DC current to maintain the generator’s output at full operating level.
When you add a load to a generator, its output voltage dips a little. This prompts the voltage regulator into action and the above cycle begins. The cycle continues till the generator output ramps up to its original full operating capacity.
IMPORTANT CONSIDERATIONS BEFORE YOU MAKE A GENERATOR BUYING DECISION
We hope that 15-20 minutes spared in reading the following article would result in a better decision for you and your Company.
A generator is major equipment, which a Company adds to its inventory of machines. It is a capital expense decision and the Company enjoys its benefits for a long time to come (even ten years or more). Therefore, care must be exercised that all factors are duly considered before making the final decision. In this article, ESL tries to outline major considerations, which the buyer must take into account:
- Go for best-in-class!
It should be equipped with a top of the line engine, alternator, controller, etc.
- Your machine should feel home in rugged conditions.
The product should be meant for the hot, harsh and humid conditions of Pakistan market and a truly 50 degree C radiator should be an integral part of the scope of supplies. No compromise should be made in this regard.
- Your product should have tasted success where it matters the most.
The product should be known to have a high degree of success in Middle East, Africa markets where extreme conditions prevail.
- Should have the capability to run round-the-clock.
It should be an equipment meant for unlimited prime operations, which is the only suitable rating applicable to Pakistan’s market in the context of the duration of power outages. Standby rating is a misnomer for Pakistan’s market and is appropriate only for those countries where continuous supply of electricity is possible without any interruption. These points are discussed in more detail in the article of Generators rating.
- Should meet quality standards.
The product should meet all quality standards relevant to diesel power generation e.g. ISO 3046, VDE 0530, BS 4999, BS 5000, IEC 34, etc.
- Your Generator should be in safe hands after you purchase it.
A fully functional after-market network of the supplier should be available to look after the generator in terms of effective design, engineering, generator sizing and safe installation for a long time to come. A track record should be thoroughly checked in this regard with a focus on the existing customers’ profile and after-market capability of the supplier Company. For more details, please refer to the articles related to Generators sizing, installation and after-sales services.
- Watch out Total Cost of Ownership (TCO).
In Pakistan, fuel contributes almost 90% to the total cost of generation (per kWhe) for diesel generators. Therefore, it is essential that specific fuel consumption of the chosen equipment should be as low as possible to achieve the lowest total life cycle cost.
- Chosen machine should be able to parallel with others.
The equipment, especially above 500 kVA, should be able to parallel with others. Consideration should be given to selecting a number of small units instead of one large unit, especially when the load is variable. Paralleling of generators if carefully exercised often results in sum of the parts being greater than the whole. This is described in more detail in the article on paralleling of gensets. This point is also very important from the perspective of future expansion.
- Go for user friendly controllers!
Care should be exercised to avoid proprietary controllers which are not customer friendly and use an expensive array of control cards leaving the customer at the mercy of the supplier for all times to come.
- Consider high torque bearing capability.
Consideration should be given to the “single step load acceptance” characteristics of the engine. A higher value is always an advantage.
- Rough-and-tough sets should be preferred over nice-and-easy version.
If the sets are to be used in rental operations, it is better to choose a generator with skid fabricated with strengthened channel and base fuel tank made of solid steel. This ensures longer life, safer operation, easier deployment / un-deployment.
- Canopies should match Generator in terms of reliability and durability – icing is as important as the cake itself.
Canopy should be made to last as long as the set itself. It should preferably be made with thick steel sheet, of bolted construction instead of welded type. The canopy should be painted with long lasting powder coated paint. All these things ensure longevity of the canopy.
- Consider Bump-less transfer between WAPDA and the generator(s).
Bump-less transfer of power between WAPDA and generator should also be considered as it can eliminate interruptions to the customers’ operations. The resulting savings can ensure a fast payback on additional investment. This is described in detail elsewhere.
- Consider Load and demand management for greater flexibility.
Load management and demand management panels may also be considered as they provide load add / shed facility in view of gensets availability or conversely automatic switching on / off gensets in view of the load required to be serviced.
- Consider savings from Cogeneration
While selecting large generating sets, considerations should also be given to engine exhaust volume, temperatures and jacket water heat content from the standpoint of steam generation,
which may be utilized for absorption chilling or for other in-house purposes. More details can be obtained from the article related to Cogeneration.
Why Customers choose Aksa generators?
ESL supplies gensets from Aksa Turkey. Turkey is a fast-emerging economic power and is rapidly gaining access to the markets of Western Europe, North America, Middle East, Africa, etc. by virtue of its quality and excellent business reputation. Aksa is amongst one of the leading companies in Turkey. An Aksa generator consist of the following features as an essential part of its scope of supplies:
Rental Grade Equivalence
Aksa generators are resilient, rugged and robust and correspond to rental grade specifications. Rental grade generators are designed to use in merciless conditions which include harsh, hot summer, chilling winter, dusty and corrosive surroundings, continuous and uninterrupted incidence of ruthless loads, etc. They consist of the following characteristics:
- Portability: Capability to easily move from one place to another.
- Durability: The sets which are suitable for rental operations can also successfully meet the other requirements on long term basis.
- Ease of Use: Rental grade generators can be easily used without the complicated steps of set up, which is an important aspect for other applications.
- Ease of Maintenance: To cater the requirements of rental operations, such generators are required on which operators having little knowledge or less experience of generators can work easily. This is why quantity of complex/Proprietary cards and components is kept low in Aksa generators.
Because of the above-mentioned reasons, our generators are extensively used for rental basis.
Building Blocks
- Engines: Aksa uses Cummins and Perkins engines. All of these have a wide network of customer support in Pakistan.
- Controllers: Aksa sets are equipped with Deep Sea or Woodward controllers, which consist of the following features:
- These controllers are universally used by major genset manufacturers worldwide.
- They are based on far fewer components (3 only) as against an array of discrete components / cards (up to 9) from others. Fewer cards make troubleshooting not only easier but inexpensive also.
- Standard AVRs and EFC cards are used which are readily and inexpensively available in the market.
- Per phase KVA, KW, KVAR, Power Factor monitoring is available.
- Digital paralleling signals are available. This ensures that maximum distance between two paralleling gensets can be as high as 1200 feet (10 times vs. analog). This allows generators to be more freely and conveniently placed in accordance with the available space.
- They put a stop to customers’ dependence on suppliers with proprietary controllers, which allows them advantage in terms of high prices for repair and replacement of components.
- Radiators: Aksa uses truly 50 degree C radiator, which is made in its own factory and ideally suited to harsh, hot and humid weather conditions existing in Pakistan.
- Skid: Skids made of solid steel are used in Aksa generators and steel fuel tanks are the necessary part of their scope of supplies. Because of solid skid and high quality Vibration pads, generators can work without vibrations for longer duration.
- Canopies: Aksa provides imported sound proof canopies with its generators, which are skid mounted. They comprise the following features:
- 2mm sheet steel bolted type fabrication, whereas other canopies available in the market are of thin steel welded-type fabrication
- Electrostatic polyester powder paint,
- Thermally insulated silencers instead of asbestos cladding,
- Emergency push button.
- Additional Standard accessories: Circuit Breaker, Trickle Battery Chargers, Lube oil drain / Filling pumps, Jacket water Heater and Wiring Harness in accordance to military grade are available as standard items without additional cost. Most suppliers sell generators without these items in order to express their product as a low cost/affordable one.
Salient features of AKSA Generators
- Suitable for unlimited hours of use: Aksa sets are designed for Prime rating for unlimited hours of operations.
- Economical usage: Aksa sets have low specific fuel consumption which ensures low total life cycle (TLC) cost.
- Single Step Load Acceptance characteristic: Aksa sets have high single-step-load-acceptance characteristics.
- Warranty Administration: Not only the record of failure of Aksa gensets within the warranty period is highly satisfactory (only 0.7%), but the Company is also generous in this regard.
- Medium Voltage availability: Up to 2000 kW Medium voltage generators, i.e. 11 kV, are easily available with Aksa and their lead time is usually shorter than that of other suppliers, with a reasonable price difference. This is why ESL maintains an excellent record of providing these kinds of generators.
ESL Value Addition
- Aksa sets can easily be paralleled with other sets of any make, model and manufacturer. This is evident from our various accomplished projects.
- Bump-less transfer between utility and on-site generators can be provided at an affordable price, which pays itself back in matter of months. This can be provided on existing sets also of any make and manufacturer.
- Load Management and demand management features are available at a fraction of price of others. This can be provided on existing sets also of any make and manufacturer.
- Facilities of Remote monitoring, integration with Building Management System (BMS) and Cogeneration can also be provided.
In short, Aksa generators, because of their strong skid steel fuel tanks, heavy duty radiators and state-of-the-art canopies, are very popular in rental operations, banking and communication industry etc. worldwide, especially in the regions of Middle East and Africa.
Next time when you plan to buy a generator, please remember ESL in order to avail quality products and services and contact us at customercare@eslpk.com or support@eslpk.com
KNOW YOUR GENERATORS
What does a generator do?
Generators are useful appliances that supply electrical power during a power outage and prevent discontinuity of daily activities or disruption of business operations. Generators are available in different electrical and physical configurations for use in different applications. In the following sections, ESL explains how a generator functions, the main components of a generator, and how a generator operates as a secondary source of electrical power in residential and industrial applications.
How does a generator work?
An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output. It is important to understand that a generator does not actually ‘create’ electrical energy. Instead, it uses the mechanical energy supplied to it to force the movement of electric charges present in the wire of its windings through an external electric circuit. This flow of electric charges constitutes the output electric current supplied by the generator. This mechanism can be understood by considering the generator to be analogous to a water pump, which causes the flow of water but does not actually ‘create’ the water flowing through it.
Faraday’s Principle:
The modern-day generator works on the principle of electromagnetic induction discovered by Michael Faraday in 1831-32. Faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field. This movement creates a voltage difference between the two ends of the wire or electrical conductor, which in turn causes the electric charges to flow, thus generating electric current.
What are the main components of a generator?
The main components of an electric generator are:
- Engine
- Alternator
- Fuel System
- Voltage Regulator
- Cooling and Exhaust Systems
- Lubrication System
- Battery Charger
- Control Panel
- Main Assembly / Frame
COGENERATION – KILLING MANY BIRDS WITH ONE STONE
Steam is very powerful. It does not only run an engine but also possesses the ability of air conditioning besides its various uses. Diesel and/or gas generators not only produce electrical power but may also produce steam which may be used for heating or cooling. This is like killing many birds with one stone. Technically, this is known as Cogeneration.
Cogeneration, also known as Combined Heat and Power (CHP), is the on-site production of multiple types of energy — usually electricity, heat and/or cooling — from a single source of fuel. Cogeneration replaces the traditional methods of acquiring energy, such as:
- Purchasing electricity from the power grid like Karachi Electric (KE) or WAPDA
- Separately burning natural gas or oil in a furnace to produce heat or steam.
- Using the resultant steam to produce air conditioning through vapor absorption cycle.
The traditional method of purchasing electric energy from a utility is very inefficient and wastes almost 75 percent of the energy in the original fuel due to production and transportation (transmission) losses.
Typically, the energy balance is as under:
- Energy input – 100%
- Energy wasted in generation – 60%
- Energy wasted in transmission – 10 to 15%
- Energy delivered as electrical output – 30%
On-site cogeneration systems convert 70 percent to 90 percent of the energy in the fuel that is burned into useful electricity or heat.
Let’s try to understand which power generation installations are the most suitable for cogeneration. Almost any facility with a simultaneous need for both electric and thermal energy is a potential candidate for the energy saving benefits of cogeneration- that is, on-site systems that produce both electric power and thermal energy from a single source of fuel. Ask yourself the following questions and if the answers to all are “yes”, then your facility may be a good candidate for a cogeneration application.
- Is the electrical load of your facility consistently greater than 1,000 kW?
Note: Facilities with larger energy needs can generate larger savings and have a shorter payback period.
- Is the thermal load of your facility equal to 1 million Btu / hour or more?
(a) This could take the form of hot water, an absorption chiller load, low-pressure steam — or a combination of all three.
- Is the duration of your simultaneous need for heating/cooling and electric power greater than 4,000 hours per year?
- Is the cost of electricity significantly higher than cost of natural gas?
(a) Greater the differential between the price of electricity and the price of natural gas (equivalent Btu basis), greater the likelihood of savings.
- Is reliability of electric service a major economic concern?
(a) For many commercial and industrial facilities, a power outage can be very costly. On-site cogeneration systems, when designed properly — offer significantly better reliability than local utilities. They are less vulnerable to vandalism and transformer or transmission line failures, and, with proper maintenance, will offer decades of reliable operation.
Sources of heat:
The thermal energy contained in the exhaust gas and cooling systems generally represents 60 to 70 percent of the inlet fuel energy. Waste heat from engine is available in the following:
- Engine exhaust
- Jacket coolant,
- Lube oil cooler and
- Turbocharger’s intercooler and after-cooler (if so equipped).
Amount of heat recovered is in direct proportion to the:
- Exhaust gas mass flow rate, exhaust temperatures and minimum temperature exhaust can be cooled down to.
- Mass flow rate of cooling water in LT and HT circuits and maximum outlet temperatures achieved respectively from both.
It is important to note that:
- Heat in the engine jacket coolant accounts for up to 30 percent of the energy input and is capable of producing 90 to 95°C hot water.
- Engine exhaust heat represents from 30 to 50 percent of the available waste heat. Exhaust temperatures of 450 to 650°C are usual.
- By recovering heat in the cooling systems and exhaust, approximately 70 to 80 percent of the fuel’s energy can be effectively utilized to produce both power and useful thermal energy.
- Exhaust heat is typically used to generate hot water to about 100°C or low-pressure steam (up to 150 psi).
- Only a portion of the exhaust heat can be recovered since exhaust gas outlet temperatures are generally kept above a certain level (120 to 180°C) to prevent the corrosive effects of condensation in the exhaust piping.
- Exhaust heat recovery can be independent of the engine cooling system or coupled with it. For example, hot water from the engine cooling can be used as feed water or feed water pre-heat to the exhaust recovery unit. In a typical heating system, jacket cooling, lube oil cooling, single stage after-cooling and exhaust gas heat recovery are all integrated for steam production.
- Heat which is required to convert feed-water at 100 °F (38°C) into steam at 150 psi (15 bar) is equal to 1128 BTU
- Quantity of 100 to 150-psig steam which is required to produce one ton of refrigeration / air-conditioning is 10 lb (4.5 kg.)
It is due to the above reasons that Cummins gas generators are the most efficient for cogeneration. This total efficiency is the hallmark of Cummins gas generators and the basis of Lowest Cost of Ownership! For more advice on co-generation, please contact us at custoemrcare@eslpk.com
Allow No Interruption in Operations – Use Bump-less Transfer between Utility Transformers and On-site Generators
Most loads can tolerate a short break in power. Hospital emergency power systems, for instance, are designed to handle short power breaks as long as power is restored to vital circuits within ten seconds. Emergency loads requiring fast restoration are supplied by engine-generator sets that start upon failure of the normal supply and a transfer switch, which transfers the vital load from utility supply to the alternate source when it becomes available. Typically, there will always be a break in power to the load anytime the load is switched, even if both power sources are available. The key factor in these systems is maximum reliability. A momentary interruption is acceptable; a sustained or prolonged interruption is not!
On the contrary, there are some mission critical applications, where even momentary interruption is not liked and power continuity is considered important for life, safety or economic reasons. These applications require two independent sources of power viz city-power and on-site power generation. In the event of a failure or abnormality of the city-power supply, the vital load is transferred to the on-site power generators.
Ideally, this transfer should cause no interruption to the load and should involve no major transients. It is possible to accomplish such a transfer where the application requires absolute continuous, “no-break” power at all times. To do so, it is essential that both sources of power be continuously available.
Currently, systems consisting of modified transfer switches (closed transition transfer) are proposed as an economical way to accomplish “no-break” switching. The devices achieving these are called bump-less transfer panels.
ESL provides these panels based upon Deep Sea Controllers, which can also take advantage of the scheduled power outages in the main cities and thus provide no-break power transfers on either side of the mains failure. The site-generator is started shortly before the scheduled mains outage. As it attains required speed and voltages, the site load is transferred from mains to the generators, without interruption, using passive synchronization. Same cycle is repeated upon restoration of the mains and there is no interruption in the operations, no loss of productivity, whatsoever.
Let us now review the transfer systems very briefly and see how they function:
TRANSFER SYSTEM
- OPEN TRANSITION
- The conventional transfer of a critical load between power sources is accomplished with a double-throw (either city-power or site-generator) transfer switch arrangement. Historically, transfer switches have been designed with a positive mechanical interlock that absolutely prevents both sources being closed to the load at the same time.
- There will always be a break in power until the alternate source is available.
- In most instances, it is desirable to have a short time delay before retransferring the load automatically in order to assure that the utility supply is going to remain available.
- This is also called break-before-make transfer system.
- CLOSED TRANSITION TRANSFER SWITCH (CTTS)
- When testing a system (no actual power loss) and when returning the load to its normal source, both power sources are available, and it is possible to accomplish a “no-break” transfer. All “no-break” transfer schemes involve paralleling of the two sources for some period of time. Since conventional transfer switches have mechanical inter-locks to positively prevent paralleling of the two sources, they cannot be used. It is necessary, therefore, to either:
- Replace the transfer switch with paralleling circuit breakers and controls.
- This requires replacing the transfer switch with two electrically interlocked circuit breakers, synchronizing controls, some type of power transfer control, and a full set of protective relaying for both sources.
- If only one power source is available, the circuit breakers operate in a “break-before-make” configuration, the same as a conventional transfer switch (but without the positive mechanical interlock).
- If both power sources are available (while testing and retransferring), the synchronizing controls bring the alternate source engine-generator into synchronism with the normal utility source, parallel them, and gradually shift the load from one source to the other.
- This type of system can provide a “no-break” transfer during test and re-transfer to city-power.
- Provide a modified transfer switch that has overlapping contacts some of the time (closed transition transfer switch – CTTS).
- In the event of an unscheduled power failure, this transfer switch operates in a conventional “break-before-make” mode.
- However, before a scheduled power outage and during retransfer upon restoration of city-power, the sources are paralleled (make-before-break). To accomplish this, the mechanical interlock has been removed.
- Relays are provided to check the relative phase relationships and the relative voltage and frequencies of the two sources. When the voltage and frequency are within approximately 5% and the phase relationship within approximately 15%, a signal is given which causes both sets of contacts of the transfer switch to be closed to the load at the same time, paralleling the two power sources.
- After a brief period, one side of the switch is opened, leaving the load connected to the other source. The transfer thus occurs with no apparent break in power.
- Protective relaying is not necessary (since the sources are only in parallel for a short duration, i.e., 100 milliseconds).
- As no active synchronizing controls or protective devices for either source are provided, generally, the cost of such a system is lower in comparison to true paralleling controls.
- As these systems do not employ any active synchronization, there is no way to automatically adjust the voltage or frequency of either source. There can be issues with respect to power transfer control to gradually transfer the load between the two sources.
- The sudden application or removal of large block loads from the engine-generators, as they are paralleled with a utility, can cause system disturbances which can be detrimental to a sensitive load.
- Care should be exercised as in the event of a utility failure, an on-site power source, paralleled with the utility grid, even momentarily, could energize utility lines.
- Incorrect paralleling of an on-site generator with the utility can result in destruction of the engine-generator itself.
SUMMARY
Conventional open transition transfer switches offer a proven reliable method of transferring between two power sources. The power interruption that occurs with conventional transfer switches may not be acceptable in some applications. Two options are available on systems that cannot tolerate any power interruption; one is an active synchronizing method with protective relaying and meets typical utility company approval requirements. Other is a lower cost, passive synchronizing system known as BUMPLESS TRANSFER.
ESL uses marine compliant Deep Sea Controllers for bump-less transfers. These allow:
- AMF operation,
- Synchronization between generators and utility transformers (real and reactive power load sharing with up to 32 generators),
- Breaker monitoring and control,
- Open- close control of breakers
- Open / closed transition between generators and utility,
- Active / passive synchronization,
- Soft loading / soft unloading through programmable operation sequences using Deep Sea’s DSE Controller software, which enables adapting to specific needs.
To install bump- less transfer systems on your existing generators, please consult ESL at customercare@eslpk.com and get a return on investment of less than a year.
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