RU197599U1 - Device for monitoring the operability of photothyristors for protection against arc faults - Google Patents

Abstract

The utility model relates to the field of power electronics and is designed to monitor the health of photothyristors. The device for monitoring the serviceability of arc thyroid protection photothyristors contains a power source and two arc protection buses connected to it in series, to which an arc protection input / output key, photothyristors and intermediate relays are connected. The device is equipped with a voltmeter connected in parallel to the photo thyristors through the photo thyristor selection key. Effect: increasing the reliability of protection against arc faults. 1 s.p. f-ly, 1 ill.

Description

The utility model relates to the field of power electronics and is intended for monitoring the health of photothyristors.

The claimed utility model can be used in the operation of photo thyristors on an integrated switchgear type RU-6/10 kV.

The prior art device for monitoring the state of the thyristor, which contains a controlled thyristor, a power source during the conducting periods of the thyristor and the measuring complex. The measuring complex is additionally equipped with a reverse current sensor. The thyristor state monitoring device is additionally equipped with a device for generating signals of a given shape, an additional power source during non-conductive periods of thyristor operation, and an uncontrolled thyristor connected in parallel with a controlled thyristor. In this case, the anode and cathode of the controlled thyristor are connected respectively to the cathode and anode of an uncontrolled thyristor (RU 2420752 C1, IPC G01R 31/26, Н02Н 7/12, publ. 06/10/2011). This device is taken as the closest analogue.

The disadvantage of the analogue is the inability to check the thyristor by the parameter of the voltage drop at the pn junction, which does not allow predicting possible malfunctions.

The task the utility model aims to solve is to eliminate the aforementioned drawback, as well as to prevent cases of false triggering of protection against arc faults (ZDZ) performed on photothyristors by checking photothyristors in existing complete switchgears for the voltage drop parameter.

The technical result is to increase the reliability of the ZDZ.

The technical result is achieved by the fact that the health monitoring device of the ZDZ photothyristor contains a power source, two arc protection buses connected in series with it, connected to two arc protection buses, an arc protection input / output key, photo thyristors and intermediate relays, while the device is equipped with a voltmeter, connected in parallel to the photo thyristors, with the ability to measure the potential difference of the photo thyristors through the photothyristor selection key.

A cam switch may be used as a photothyristor selection key.

In existing circuits for the organization of ZDZ of a switchgear RU-6/10 kV, ZDZ on photothyristors is widely used. The difference between the thyristor and the thyristor is that the thyristor controls the signal to open it (i.e., the beginning of the voltage passing through the thyristor) is an electric signal, and the light of the thyristor is such a signal.

During short circuits in high-voltage electrical installations powered by switchgears, a powerful electric arc arises, which is accompanied by a bright glow. The photo thyristor catches a flash of light and sends a signal to the relay protection devices. The relay protection device disconnects the damaged area according to two conditions:

1) the presence of a signal from the photothyristor;

2) the excess of the current allowable value, determined by the setting of the operation of the remote sensing.

The state of the thyristor is characterized by the resistance of the pn junction. In the event of a photothyristor malfunction (i.e., when it becomes open without a control action), the resistance of the pn junction decreases, which indicates the development of the defect and the possible occurrence of a malfunction. In this case, the photo-thyristor can send a false signal about the "presence" of a short circuit, and the relay protection device will perceive this false alarm of the ZDZ and give a signal "ZDZ malfunction".

When starting high-voltage electric motors of the main pumping station (MNS) or booster pump station (PNS) through the switchgear RU-6/10 kV, the trip currents of the ZDZ at the time of start-up can exceed the set value. If there is a signal from a faulty photothyristor, the relay protection device will falsely disconnect the switchgear supplying the MHF and PNS, in which the ZDZ is installed on the photothyristors, which will lead to a complete stop of the pump station (MNS or PNS).

The claimed device for monitoring the health of photo-thyristors ZDZ reveals the first signs of a decrease in the resistance of the pn junction, which allows to identify the need for the output of ZDZ from work or replacement of the photo-thyristor. Replacing a faulty photo thyristor eliminates the possible false triggering of relay protection devices, which increases the reliability of the stable operation of the ZDZ, while the proposed solution allows you to continuously monitor the status of the photo thyristor, since it is constantly included in the switchgear circuit.

A utility model is illustrated in FIG. 1, which shows a functional diagram of a device for monitoring the health of photo thyristors ZDZ.

The list of items in FIG. 1:

1, 2 - photothyristors;

3, 4 - intermediate relay ZDZ;

5 - voltmeter;

6 - key input / output ZDZ;

7 - a key for selecting a thyristor;

8, 9 - shields of arc protection.

The claimed utility model contains a power source (not shown in Fig. 1), two arc protection busbars (8, 9) connected in series with a power source, connected to arc protection busbars (8, 9) ZDZ input / output key (6), photo thyristors (1,2), intermediate relays (3, 4), and a voltmeter (5), in parallel to the photothyristors (1, 2), with the possibility of measuring the potential difference of the photothyristors (1,2) through the photothyristor selection key (7).

The operation of the health monitoring device of photo thyristors of protection against arc faults is as follows.

In the ZDZ device, the response signal of the photothyristors (1,2) is transmitted through the intermediate relays (3, 4) and is signaled by the arc protection busbars (8, 9) for subsequent disconnection of the switchgear (not shown in Fig. 1) by the operator using the ZDZ I / O key (6).

To diagnose the state of health of the ZDZ using a voltmeter (5), the voltage drop across the photothyristors (1,2) is monitored (with a working photothyristor, the voltage on the voltmeter is = 220 V, with a decrease in the resistance pn of the junction of the photothyristor, the voltage decreases). The device for monitoring the health of photothyristors ZDZ contains a key for selecting a photothyristor, made, for example, in the form of a cam switch (7), through which the selected element is selected. In the first position of the photo-thyristor selection key (7), the photo-thyristor (1) is controlled, and in the second position, the photo-thyristor (2) is controlled. The operator servicing the switchgear RU-6/10 kV, with a decrease in voltage ≤220 V on the voltmeter (5), can quickly take out the ZDZ from work using the I / O key of the ZDZ (6).

Claims (2)

1. A device for monitoring the operability of arc thyroid protection photothyristors, comprising a power source, two arc protection buses connected in series with the power source and connected to two arc protection buses, an arc protection input / output switch and intermediate relays, the device being equipped with a voltmeter made with the possibility of parallel connection to the photo thyristors for measuring the potential difference of the photo thyristors using the photo thyristor selection key. 2. The device according to claim 1, characterized in that the photothyristor selection key is made in the form of a cam switch.

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