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Electric power generators have a wide variety of applications that include supplying backup power in case of emergencies. The purpose of emergency power supply systems (EPSS) is different than the prime and continuous power generators. The prime and continuous power generators are primarily needed in remote areas of the world where the grid does not reach, or where power from the grid is unreliable.

Green Power-Forward Looking Issues for Generators
Introduction

Electric power generators have a wide variety of applications that include supplying backup power in case of emergencies for commercial establishments and businesses, an emergency standby generator provides an added level of insurance to keep up with the day to day operations running smoothly without interruption. Generators can also provide protection against voltage fluctuations in the power grid and can protect sensitive computer and other capital equipment from unexpected failure. Note that the purpose of emergency power supply systems (EPSS) is different than the prime and continuous power generators. The prime and continuous power generators are primarily needed in remote areas of the world where the power grid does not reach, or where power from the grid is unreliable.

Whereas the specification of a standby power generator must meet the specific technical requirements for the businesses; a business must consider several other critical aspects before making the purchase. Obviously the most important consideration is business continuity and subsequent cost. The environmental consideration is getting significant attention these days because of the incredible amount of pollution these generators add to the environment. One solution to this problem is to use clean-burning fuel for these generators.

Diesel is the fuel of choice for these standby electrical power generators because of its high power density and availability. However, natural gas is becoming a cleaner fuel option for such generators. There are several reasons for that:

•Natural gas produces lower emissions while providing a highly economical electricity source.

•Natural gas-generators perform very well under intermittent load conditions.

•Parts and service technicians for natural gas generators are widely available.

To make use of the benefits of natural gas, an effort is underway to use natural fuels to replace (or to use in conjunction with) diesel used in gensets in commercial establishments. Altronic Inc (with GTI acquisition) has innovative systems that allow operators to use two fuels (natural gas and diesel) together for the same genset. This feature gives the user the flexibility to choose between gas and diesel modes as dictated by fuel pricing, fuel availability, or other operational considerations such as efficiency. The end result is that operators benefit from this fuel flexibility and all of the economies associated with it.

Going beyond the above, commercial establishments and businesses must be forward looking in the years to come, as several vendors are working on green power generators that reduce Carbon Monoxide and NOx (Nitrogen Oxide) emissions, as compared to today’s generators. Unlike standard generators which idle for hours and spew smoke – adding greenhouse gas- into the air, green- powered generators provide cost effective and environmentally friendly power that benefits society.

We at Prime Power are the GTI Distributor for Tennessee, North Caronlia, South Carolina, Georgia, Alabama, and Mississippi. Or talented engineers can help you achieve yhour goal of using clean-burning fuel and increasing the efficiency of your generators. We offer unparalleled customer support to back up our quality equipment.

Engineering

Automatic transfer switches safeguard data and telecommunication networks, industrial processes and critical instillations such as health care facilities and financial transaction centers. The main goal is to provide electrical power to the facility loads (during a power outage) from the standby generator without backfeeding that can damage utility equipment and hurt (or kill) utility workers.

Automatic Transfer Switch
An automatic transfer switch is an integral component of an emergency power supply system (EPSS). This transfer switch allows safe switching from utility power to standby generator power while maintaining isolation of each source from the other. The main goal is to provide electrical power to the facility loads (during a power outage) from the standby generator without backfeeding that can damage utility equipment and hurt (or kill) utility workers. Automatic transfer switches safeguard data and telecommunication networks, industrial processes and critical installations such as health care facilities and financial transaction centers.

Automatic transfer switches continually monitor the incoming utility power. If the normal power source, often the utility, fails or exhibits some anomalies such as voltage sags, spikes or surges, these switches detect this loss of power (or anomaly) and send a start signal to the standby generator. The switches connect the generator to the facility loads when the generator has achieved proper frequency and voltage. When utility power returns or no anomalies have occurred for a set time, the transfer switch will then transfer back to utility power. It will instruct (command) the generator to turn off, after a specified amount of “cool down” time with no load on the generator. Electrical power to a facility’s loads will be lost for a period of approximately 10 seconds while the generator set starts–unless there is an uninterruptible power supply (UPS) serving loads in the system– to bridge the power gap while the generator set starts.

Power system specialists can set up a transfer switch to provide power only to critical circuits or entire electrical (sub) panels. Some transfer switches allow for load shedding or prioritization of optional circuits, such as heating and cooling equipment.

There exist three different ways in which a transfer switch can provide power-switching operation:

•Open Transition – Break-before-Make operation

•Closed Transition – Make-before-Break operation

•Closed Transition Soft Load – Both sources are paralleled

The three (3) functional components of a transfer switch are:

•Power switching device to shift the load circuits to and from the power source

•Transfer Logic Controller to monitor the condition of the power sources and provide the control signals to the power-switching device.

•Control power source to supply operational power to the controller and switching device

Power system specialists should test automatic transfer switches on a monthly basis for EPSS in accordance with NFPA (National Fire Protection Association) Code 110. This standard also requires a monthly generator run. There are two main steps for such testing: 1) automatic generator start that is initiated by the transfer switch, 2) automatic transfer of facility load onto the standby generator.  During the test, the specialists should also take appropriate action when power interruption to the facility load is a matter of concern.

For existing facilities, the engineer must determine the loads that may actually suffer negative impact from monthly interruptions in power. One solution for this is to use UPS for protection from these negative impacts. Also, engineers can replace existing open transition switches with closed transition switches.

The testing of a transfer switch establishes the following:

•The switch is not going to fail during a transfer

•Moving parts will continue to operate smoothly

•Transferring capacity to the standby generator will be very smooth

How Prime Power can help you with different automatic transfer switch related services

We at Prime Power provide the installation, testing, troubleshooting, and maintenance of your automatic transfer switch. You can rest assured of the quality of the automatic transfer switches that we offer. They are safe, reliable, rugged, versatile, and compact assemblies for transferring essential loads and electrical distribution systems from one power source to another. Prime Power can deliver transfer switches in separate enclosures for stand-alone applications, or as an integral component of other equipments such as switchgear.

If your business relies on safeguarding data on telecommunications networks, industrial processes and critical installations such as health care facilities and financial transaction centers, we can help your business by installing high-quality automatic transfer switches for your EPSS.

Prime Power’s automatic transfer switches are characterized by:

•Fewer moving parts resulting in higher reliability

•Inherent double-throw operation

•Silver alloy main contacts (highly conductive) and arcing contacts (resistant to heat)

•Repeatable fast transfer operation

•Safe manual operation under load (without opening door)

•Slow switch operation for maintenance and adjustment.

•UL listing with “any breaker”

Prime Power also provides high-quality services such as:

•Engineering, design, and service responsibility, all under one roof

•Staffed service centers that operate 24/7. Service vans that are stocked with parts and not dependent upon supply from other manufacturers

We understand that automatic transfer switches require regular maintenance including preventive maintenance in the form of testing. Our engineers are highly experienced to carry out testing of automatic transfer switches to see you and your business prepared for a power-outage emergency.

Maintenance

Load bank testing of standby gensets is a preventive maintenance practice for an emergency power supply system (EPSS). The testing is primarily meant for diesel-powered gensets. The main purpose of this testing is to help ensure the genset’s reliable operation during utility power failure. If this testing is performed regularly, it can extend the genset’s life.

Load Bank Testing
Load bank testing of standby gensets is a preventive maintenance practice for an emergency power supply system (EPSS). The testing is primarily meant for diesel-powered gensets. The main purpose of this testing is to help ensure the genset’s reliable operation during utility power failure. If this testing is performed regularly, it can extend the genset’s life.

When conducting load bank testing, plant engineers run gensets under a full load for an extended period of time–typically, two to four hours. However, providing such a load for this testing from the existing facility load may not be practical because of the risk of power interruption to critical computer, life safety, or communication equipment in the facility. Any interruption of power to these loads may cause a loss of data, operations, or may jeopardize personal safety.

The main reason for load bank testing is to raise the operating temperature (i.e. combustion temperature) of the gensets. In order to achieve this full operating temperature, diesel engines must operate with sufficient load for an extended period. If the engine can’t operate at sufficient load for an extended period, some fuel remains unburned; carbon builds up in the stack, and wet stacking results. Wet stacking is a common problem for diesel generators that are operated for extended periods with light or no loads applied. The unburned fuel accumulates in the exhaust system, thereby rendering the fuel injectors, engine valves, and exhaust system, foul. Wet stacking not only reduces the operating performance of the gensets, it also creates a significant fire hazard.

A generator needs to run under full load for several hours to reach the full operating temperature. This operation “burns out” the accumulation of unburned fuel and helps to get the engine and exhaust system back in shape.  When the exhaust stack smoke is nearly invisible, the system has been cleaned of excess oil, fuel, and hydrocarbon buildup.

The main requirement of such testing is a load bank, an artificial electrical load that can bring the engine up to full operating temperature. The purpose of a load bank is to accurately mimic the operational or “real” load that a genset will experience in actual application. However, unlike the “real” load, which is unpredictable and random in value, a load bank provides a contained and controlled load. This load bank may be a portable unit that is designed to be rolled up to the generator being tested or it may be trailer mounted for generator sets in the 1-3 MW range. The load bank also includes control and accessory devices required for its operation. The three most common types of load banks are resistive load banks, reactive load banks, and capacitive load banks.

Load banking of the genset tests the engine’s ability to produce the full-rated KW output and the generator’s ability to produce the KVA output. It confirms the generator’s ability to come up to full load and to provide continuous power without overheating or possibly shutting down. Testing also evaluates other critical system readings, such as oil and fuel pressure, to make sure the engine is well lubricated and is getting enough fuel to produce the power the generator requires. Power system specialists recommend testing the generator systems once a year at full load with a load bank.
The National Fire Protection Association’s NFPA Code 110 – Standard for Emergency and Standby Power Systems, 2005 Edition, specifies load bank testing for EPSS as a requirement by law where life safety electrical needs are involved. Section 8.4.2.3 of this code states the generator must be run at a supplemental load of 25% of nameplate rating for 30 minutes, followed by 50% of nameplate rating for 30 minutes, followed by 75% of nameplate rating for 60 minutes, for a total of two continuous hours.

How Prime Power can help you in load bank testing

Prime Power has the expertise and the equipment to ensure your generator systems operate efficiently when you need them. We provide experienced technical support and trained personnel to oversee load bank testing.

Prime Power has load banks that can handle wet stacking, diagnostics, and troubleshooting. We supply the load bank, cables and an experienced test engineer who will conduct the test safely. The test engineer has the ability to assess the performance of the equipment throughout the test.

Prime Power monitors critical engine parameters such as oil pressure, engine temperature or fuel pressure. We record these readings to ensure that once the unit reaches full-rated load, it runs at normal operating temperatures and pressures. We deliver a full report of the readings to show your equipment’s activity including generator output readings such as voltage, amperage, KW amount, etc.

Prime Power backs up each test with complete written reports detailing any unusual occurrences, recommended remedial work, or suggested improvements. We include a quote for any recommended work.