Woodward 723 Generator Controller

Speed control: including idle speed, rated speed settings, overspeed trip function (starting and stopping when the set speed is reached to prevent overspeed), as well as minimum and maximum speed reference limits and acceleration/deceleration rate control.

Synchronization and load control function

Engine start: When the Run/Stop contact is closed (or configured to be open), the speed reference is at idle. When the engine speed exceeds the idle/rated switching speed, the speed reference will ramp up and down at an acceleration/deceleration rate to the rated speed, which can be interrupted by temporarily closing the deceleration contact. If the idle/rated selection function is enabled, after the engine is started, the idle or ramp to rated speed is determined based on the contact position.

Synchronization function: When the engine reaches the rated speed and maintains the synchronization readiness delay time within the synchronization readiness limit, the "ready synchronization" state is achieved through Modbus ®  Convey as True. The speed reference can be adjusted by inputting or adding or subtracting contacts through the unit synchronizer to achieve synchronization with the busbar. Alternatively, after the auxiliary contacts of the generator circuit breaker are closed, the bias speed reference can be input through the system synchronizer to achieve cross busbar connection or synchronization with the grid.

Droop control: When the synchronous/droop contacts are open and the auxiliary contacts of the generator circuit breaker are closed, the following droop modes operate. Calculate the speed droop value based on the droop percentage and engine load. The engine load comes from the input of the megawatt sensor. If the signal fails, it is determined based on the output position of the actuator. At the same time, provide a "droop pulse" function to prevent the engine from sinking into reverse power when connected to the bus in droop mode.

Synchronous load distribution: When the synchronous/droop contacts are closed, and the auxiliary contacts of the generator circuit breaker are closed and the load input signal is normal, synchronous load distribution is enabled. The first online machine immediately closes the relay K4 contact on its load sharing circuit. The subsequently selected synchronous units will adjust the load according to the automatic loading/unloading rate until the load shared with the synchronized units is within the specified load sharing error range. At this point, relay K4 closes to connect to the load sharing circuit and achieve load balancing. It also has an automatic soft unloading function. When the unloading contact is closed (instantaneously), the engine load decreases at an automatic unloading rate to the unloading trip level, and then a command to open the generator circuit breaker is issued.

Megawatt control: When the auxiliary contacts, grid contacts (if used), and megawatt control contacts of the generator circuit breaker are closed and the megawatt load input is not disabled, operate in megawatt control mode. The megawatt reference value can be adjusted by adding or removing contacts, or based on internal megawatt reference or remote reference (4-20mA or Modbus) ®） Adjustment. If the remote reference input fails, the megawatt reference will lock the last healthy value.

Protection and restriction functions

High/Low Frequency Protection: In megawatt control mode, it can be configured to open the grid and/or generator circuit breakers or switch to droop mode (megawatt coverage function) when the grid frequency is too high or too low.

Limiting functions: including start-up and maximum fuel limiter (limiting excessive fuel supply or flooding during engine start-up), engine shutdown limiter, frequency load limiter (limiting engine load when grid frequency exceeds preset limits during megawatt control), boost air pressure limiter (providing fuel limitation based on 4-20mA boost air pressure input signal), etc.

Load rejection function: When the generator circuit breaker or grid circuit breaker is opened and the load is above a certain level, the load rejection algorithm takes effect, driving the actuator output to zero for a period of time to reduce speed overshoot.