SU1193745A1 - Method and apparatus for automatic frequency off-loading - Google Patents

Abstract

1. The method of automatic frequency unloading by measuring the frequency in the power system, comparing it with the start-up setting and disconnecting customers in queues with defined 1; time between them when the frequency drops below the start-up setting, which is characterized by the fact that a deep decrease without an increase in overshoot, the frequency is compared with at least one additional setpoint below the trigger setpoint and when (L decreases the frequency of the nickname) I disable this additional setpoint consumers the same queue, but with menypimi time intervals therebetween with f |. 4 SP

Description

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2.A device for automatic, frequency unloading, containing the first frequency measuring unit, time and output organs, characterized in that the time organ contains a pulse generator, a counter, a threshold organ, and a device for setting the settings; frequency organ, logical elements NOT and AND, with the first input of the logic element AND and a series-connected pulse generator connected to the output of the first measuring frequency organ, its starting, counting IR, threshold organ and output organ, the inputs of the frequency measuring organs are combined, the output of the second frequency measuring organ is connected to the first control input of the pulse generator and the input of the logical element HE, the output of which is connected to the second control input of the pulse generator, and the setting device is connected to the second entrance of the threshold authority.

one

The invention relates to an emergency automation of power systems and can be used, for example, to realize the disconnection of a part of the power system consumers and the restoration of the frequency after its emergency descent.

The aim of the invention is to accelerate the frequency recovery process with its deep reduction without increasing overshoot.

Fig. 1 shows an example of frequency recovery when it is monitored with one additional setpoint f} in Fig. 2, a block diagram of the device that implements the proposed frequency recovery method.

When the frequency in the power system is less than the setpoint (curve 1), there is a disconnection of the queues with minimal time intervals between them and the maximum frequency recovery rate occurs. With f f (curve 2), the time intervals between the queues increase and the speed of the frequency rise decreases, which makes it possible to ensure minimal overshoot. The dotted line in Fig. 1 shows the course of the frequency change when it is restored at a constant (as is typical for the AChR-P category) high speed (and IH at a low speed (b X The first option leads to a fast frequency recovery, but pain

that overshoot, second to slow frequency recovery

The device contains the first 3 and second 4 measuring bodies of frequency, the inputs of which are combined, the output of the first measuring element is connected to the first input of the logic element 5 and the series-connected pulse generator 6, the counter 7, the threshold organ 8, the output organ 9, the output of the second measuring organ frequency is connected to the input of the logic element HE 10 and to the first control output of the generator 6 pulses, the output of the logic element NOT 10 is connected to the second input of the logic element AND 5 whose output is connected To the second control input of the generator 6 pulses, a setting device 11 connected to the second input of the threshold element 8.

The device works as follows.

The measuring authority 3 frequencies (IOC) is set to the trigger setpoint E «p P measuring organ 4 to the setpoint f ,. If the frequency is lower than the setpoint (in Fig. 1, curve H), both IOCs are in the actuated state and a signal generator (IG) is started by the IOCM 3 signal, which generates the frequency of the pulses through the first control input higher than the second one. the input NOT and the first control input of the GI is present logical, IV. At the outputs of the logical O and 1, and at its output, i.e. at the second control input of the GN, the logical O, and the GI generates pulses with a frequency given on the first control input. The counter counts these pulses and sends a threshold to one of the inputs When the number of pulses reaches the setpoint set by the setpoint device, the software is triggered and, through the output organ, gives a signal to disconnect the load. If the frequency becomes higher than f before the software has worked, IQ 4 returns leads to the appearance of a logical 1 at the second control input of the CG and a logical O at its first control input. As a result, the frequency of the CI decreases and the software setpoint is reached with a longer time delay. If the frequency has not decreased below ,, (curve 2), then only IOC 3 is in the actuated state, the counter receives pulses with a lower frequency, and the load is disconnected with a longer delay time. An increase in the number of zones is achieved by simply adding the REF one and the same to the AND element and the NC element, and each additional setpoint. The above elements are included similarly to Fig. 2, i.e. the output of the last IOC is connected directly to the last control input. The GG, and the penultimate IOC, is connected through the element I. Many of the known multivibrator circuits can be used as the GI. At the same time, the pulse repetition frequency can be easily changed by switching the time of the master RC circuits. The GI can also be built on the basis of a time relay, which is switched into oscillatory mode, in which the time relay repeatedly processes the set time delay. In this case, it is more convenient to use digital time relays (for example, VL-36), since in them it is possible to change the set point relatively simply, i.e. time exposure. The serial digital time relay VL-36 includes a counter, a threshold organ, and a device for setting settings. Therefore, elements 7,8 and II can be implemented on this device.

Claims (2)

1. A method of automatic frequency unloading by measuring the frequency in the power system, comparing it with the start-up and shutdown settings of consumers in queues with defined time intervals between them when the frequency decreases below the start-up setting, characterized in that, in order to accelerate the process of frequency recovery when it is deeply reduced without to increase the overshoot, the frequency is compared with at least one additional setting below the start-up setting and when the frequency decreases below. In the same queues, but with shorter time intervals between them. SU „1193745> 2. A device for automatic, frequency unloading, comprising a first frequency measuring body, time and output organs, characterized in that the temporary body contains a pulse generator, a counter, a threshold organ, and at least a second frequency measuring organ is additionally introduced into the setting device; , logical elements NOT and AND, moreover, the first input • of the logical element AND and subsequently connected pulse generator at the input of its start are connected to the output of the first frequency measuring organ, counters k, the threshold organ and the output organ, the inputs of the frequency measuring organs are combined, the output of the second frequency measuring organ is connected to the first control input of the pulse generator and the input of the logic element NOT, the output of which is connected to the second control input of the pulse generator, and the setting device is connected to the second input threshold organ.