SU498690A1 - The method of automatic frequency unloading of the power system - Google Patents

Description

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The invention relates to the field of emergency control of power systems and is a method of automatic frequency unloading of the power system by disconnecting the load in queues depending on the absolute value of the frequency and the speed of its decrease.

The purpose of the invention is to increase reliability.

This is achieved by the fact that when the absolute value of the frequency reaches the setpoint, the frequency of the decrease in the frequency of the queues that have the speed setting is lower than the rate of reduction of the emergency mode, and the subsequent queues are turned off by the sign of the frequency of the decrease in frequency.

This method of performing automatic frequency unloading disables load queues by the following parameters: the absolute value of the frequency; frequency reduction rates; the sign of the derived frequency in time and time.

When an active power deficit occurs, the frequency in the system decreases at a rate proportional to the magnitude of this deficit. When the setpoint frequency reaches the absolute value, the queues are disconnected based on the value of the rate of decrease in frequency.

Due to the change in the parameters of the power system, as well as the power connected to the queues, the following options are possible:

a) the power of disconnected consumers is less than the resulting deficit (effect

under regulation);

b) the load power is equal to the generated power at the intermediate frequency below the nominal one (the phenomenon of "frequency hanging").

In the first case, there is a further reduction in frequency, but with a significantly lower speed due to the difference between the resulting deficit and the power cut off by the speed value. In such

mode occurs after a set time off the queue following the last one disconnected. If the sign of the derivative does not change, then the next queue will be disabled, and so on, until

the derivative sign changes.

In the second case, queues come into play that perform the function of additional unloading. At a system frequency below the absolute value setpoint, after a set time, additional queues are triggered and thus the balance at the intermediate frequency is disturbed and it is pulled to the frequency of the original mode. 34

The form of the invented value of the setpoint frequency, the method of automatic frequency unloading are part of the queues that have the power system setpoint by disconnecting the load at a speed lower than the speed of decreasing the frequency in queues depending on the absolute 5 emergency mode its reductions are disconnected by the sign of the rate of decrease of the frequency, in that, for the purpose of a new one. reliability when reaching absolute 498690 is determined by the value of the rate of decrease of an hour