pag - base loading with utility

8/12/2019 PAG - Base Loading With Utility

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Base Loading with Utility

PARALLELING APPLICATION GUIDE

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ADDITIONAL PARALLELING CONTROLS, EQUIPMENT, AND INTERFACING (SUPPLIED BY THIRD PARTY)

Paralleling switchgear, circuit breakers, and/or disconnects

Paralleling bus and cabling

External start signal source and connection to generator set Utility bus sensing connection to generator set

PROGRAMMING AND LOGIC

Basic programming and logic will be provided to start, synchronize, and base load with the utility powersource.

Site programming and system tuning are required by the customer for proper onsite operation.

OTHER SYSTEM CONSIDERATIONS

For generator sets used in non-emergency applications within EPA regulated areas, Tier 4i/T4 Final certifiedengines must be used.

SEQUENCE OF OPERATION

Base Loading Request to Generator Set

When a customer requires the generator set to parallel to a utility power source for the purpose of supplementingutility power, a base loading request can be made. The customer issues a start request to the generator set. Thestart signal is a command for the generator set to start, synchronize to utility power source, and close its circuitbreaker. All available generator sets will start and achieve nominal frequency and voltage.

Synchronization of Generator Set

The DGC-2020 controller on the off-line generator set utilizes the LSM-2020 load share module to bias itsDVR2000E(+) regulator and governor to match its speed and voltage to the utility bus. The LSM-2020 biases thespeed of the engine governor to drive the difference between the phase angle of the generator set and the phaseangle of the utility bus to zero. Additionally, the LSM-2020 biases the voltage regulator to match the generator

set voltage to the utility bus voltage. When the synchronization window criteria are met, the generator set isconsidered synchronized with the utility bus, and the DGC-2020 controller issues a command to close its circuitbreaker. Once its circuit breaker is closed and the DGC-2020 controller receives breaker closed feedback fromthe circuit breaker auxiliary switch, the generator set is considered paralleled. The LSM-2020 no longer activelyattempts to synchronize the generator set.

Base Loading

While paralleled, the generator set is electrically interlocked and will share real load (kW) and reactive load (kVAR)with the utility power source based on a percentage of the load capacity of the generator set. When the generatorset circuit breaker is first connected, the generator set produces a negligible amount of real power. TheLSM-2020 load share module will bias the engine governor to begin loading kW on the generator set at apredefined amount of load per second. Load will ramp onto the generator set until the user-defined amount ofbase load is met. The DGC-2020 controller (via the LSM-2020 load) in turn biases the engine governor to control

the real load on the generator set.

Reactive load is also precisely shared between the paralleled generator set and the utility power source. Whenthe generator set circuit breaker is first connected, the generator set produces a negligible amount of reactivepower. The LSM-2020 load share module will bias the voltage regulator to begin loading kVARs on the generatorset at a predefined amount of load per second. Load will ramp onto the generator set until the user-definedamount of base load is met. Reactive base loading can be defined in either of two manners: percentage of VARs(leading or lagging) or Power Factor (PF) set point (- Leading / + Lagging). The DGC-2020 controller in turn biasesthe voltage regulator to control the reactive load on the generator set.


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As the generator set is base loading against the utility power source, the DGC-2020 controller will constantlyadjust to fluctuations in load and in the utility power source to maintain the base load level requested.

In the event that a generator experiences a fault while supporting the load, it will disconnect itself from the utilitybus.

Termination of Base Loading Request to Generator Set

When the customer no longer wants the generator set to base load against the utility power source, the startrequest signal is removed. The DGC-2020 controller will bias the governor and voltage regulator to ramp load offof the generator set. Once the generator set is unloaded and has reached the pre-defined breaker open set pointpercentage, the circuit breaker will open. The generator set will enter a cool-down period, after which time thegenerator set will stop, re-enter standby mode, and await the next start request.


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MTU Onsite Energy

A Rolls-Royce Power Systems Brand

www.mtuonsiteenergy.com

M T U O n s i t e E n e r g y S u b j e c t t o a l t e r a t i o n d u e t o t e c h n o l o g i c a l a d v a n c e s

2 0 1 4 0 1

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Figure 1: Base Loading with Utility

The dashed line ( ) denotes wiring/equipment supplied by a third party

pag - base loading with utility

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