Load sharing

The load sharing parameter includes the settings that regulate the load within the bus bar section.

The load sharing regulator works as a three-point controller. After a certain break time, the difference between the load set point and the actual measured load value will be calculated. With this load difference the pulse time for speed higher and lower will be calculated. The set point in the symmetrical load sharing mode for the load regulator is the average net load. The set point in the asymmetrical load sharing mode is Parameter [0934]). If the load difference (set point to actual load) is lower then the dead band, the load-sharing regulator is blocked.

[0925. SYM. – switch by event :]

The function for balancing the load through the load-sharing regulator can be switched on and off by this event. All devices in one net must have this switch enabled for activation!

[0926. – characteristic :]

Switch characteristic of load-sharing ON/OFF switch Parameter [0925]:

ON -> OFF: If event of load-sharing switch is active, load-sharing function will be switched off.

OFF -> ON: If event of load-sharing switch is active, load-sharing function will be switched on.

[0927. – break time :]

Break time for the load-sharing regulator. The break time is the interval or cycle time for the regulator. At the beginning of the break time, the pulse duration for the speed control will be calculated and started.

[0928. –pulse time :]

Pulse time of the load-sharing regulator. The pulse time depends on the difference between the set point and the actual measured load of the generator. The speed control LOAD SHARING 0939. Allowed load difference: 20.0 % 0940. – delay : 60 sec

Event [0930] or [0931] will be activated as long as the pulse time is running. The pulse time will be calculated as follows:

Pulse time = load difference* Parameter [0928] / 100

Set this parameter to the max. time the engine needs to reach nominal speed.

[0929. – deadband :]

Dead band of the regulator: If the load difference (set point to actual measured load of the generator) is under the dead-band limit, the regulator is idle.

[0930. –higher event :]

Event for speed higher control. This event will be set by the system in case the pulse time of the regulator is active in combination with the demand to increase the speed. This event can be used to activate a function output.

[0931. – lower event :]

Event for speed lower control. This event will be set by the system in case the pulse time of the regulator is active in combination with the demand to decrease the speed. This event can be used to activate a function output.

[0932. AYM. – switch by event :]

Special application for load-sharing regulator. ON/OFF switch of asymmetrical load sharing function. The function for this asymmetrical mode for the load-sharing regulator can be switched on and off by setting this event.

In the asymmetrical load sharing mode, the regulator uses a fixed-load set point Parameter [0934], instead of the average net load. The asymmetrical load mode is allowed, if a minimum of two generator sets feeding the bus bar and the load limits of Parameters [0936] and [0937] are not exceeded. In case of mains parallel operation Parameter [0190], asymmetrical load-sharing mode is always allowed.

[0933. – characteristic :]

Switch characteristic of asymmetrical load-sharing ON/OFF switch Parameter [0932]:

ON -> OFF: If the event of the asymmetrical load-sharing switch set in Parameter [0932]

is active, asymmetrical load-sharing function will be switched off.

OFF -> ON: If the event of the asymmetrical load-sharing switch set in Parameter [0932]

is active, asymmetrical load-sharing function will be switched on.

[0934. – setpoint :]

Set point for the asymmetrical load sharing regulator. The range for this set point is 0--100% of the nominal load of the generator. This parameter can be changed also on the load page (Asymm. load).

[0935. –analog input :]

Analogous setpoint for the asymmetrical load-sharing regulator. The set point for asymmetrical load limit can be set by the analogous input. One of the four analogous inputs of the basic unit can be used to modify the setpoint for the asymmetrical load sharing (refer to chapter 2.5. to enable the selected analog input).

Note: If this parameter is enabled the setpoint of parameter 934 is inactive.

[0936. –range minimum :]

[0937. –range maximum :]

Minimum and maximum limit for the asymmetrical load-sharing mode.

If the asymmetrical load-sharing is switched on (Parameters [0932] and [0933]) and if the load of the other generators feeding the same bus bar is within the minimum and maximum range limit, then the asymmetric mode will be allowed.

[0938. – next attempt :]

If the asymmetrical load-sharing mode is active and one of the other generators that is feeding the same bus bar exceeds the limits of Parameters [0936] and [0937], then the load-sharing mode is switching from asymmetric to symmetrical load-sharing mode.

After the delay time set in Parameter [0938 ], the load-sharing regulator tries to switch again into the asymmetrical load-sharing mode.

[0939. Allowed load difference :]

If the difference from the set point to the measured generator load exceeds this limit, then Event [0939] will be activated. (DNV load sharing supervision rule).

[0940. – delay :]

Delay time for Parameter [0939]. Use this event [0940] to activate an alarm channel.

[0941. REGUL. – switch by event]

With this function the load sharing regulator can be switched to another break and pulse time. This can be used to change the regulator characteristic for different operations.

[0942. – 2. break time]

This second break time is valid for the regulator if the event from parameter 941 is active (Refer to parameter 927).

[0943. – 2. pulse time]

This second pulse time is valid for the regulator if the event from parameter 941 is active (Refer to parameter 928).