JPS59194625A - Fm current differential carriage protective relaying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carrier protection relay device that identifies faulty sections of a power transmission system using carrier waves and controls circuit breakers provided at both ends, and particularly relates to instantaneous values of system current in power transmission lines. This invention relates to an FM current differential transfer fishing relay device which frequency-modulates and transmits between electrical stations, and performs differential determination at least at the negative electrical station to protect the power transmission line.

In recent years, automatic monitoring circuits are increasingly being provided in protective relay devices for high reliability and labor saving.

In this case, the most reliable way to check for changes in the characteristics of the relay is to apply a simulated input from the primary voltage or current input circuit.

Conventionally, there has been an example of automatic inspection of this type of FMM flow differential relay as shown in FIG. In the figure, 1 is a current-voltage conversion circuit that inputs a grid current and converts the current into voltage; 2 is a VF conversion circuit that FM modulates a voltage waveform;
6 and 4 are coupling boards that interface with transmission equipment such as carrier terminal equipment, 5.6 is an FV conversion circuit that demodulates the FM modulated wave to the original voltage waveform, 7 is a differential determination circuit, and 8 is a check input an application circuit; 9 is an inspection control circuit that controls inspection input;
10 is an oscillation circuit that generates a pilot signal, 11 is a VF
A synthesis circuit that combines the FM carrier wave from the conversion circuit 2 and the pilot signal from the oscillation circuit 10, 12 a bandpass filter that separates the FM modulation wave from the received signal, and 16 a bandpass filter that detects abnormalities in the received FM modulation wave and 14 is a low-pass filter that separates the pilot signal from the received signal; 15 is a frequency fluctuation detection circuit that detects alternating frequency fluctuations of the pilot signal and locks the differential determination circuit 7; be. Note that the frequency arrangement of the FM modulated wave and the pilot signal described above is realized as shown in FIG. In the figure, 16 is an FM modulated wave, which varies within a range of, for example, 1900Hz±1000Hz. Also,
17 is a pilot signal, which can be, for example, 425 Hz.

In the apparatus configured as described above, when carrying out an inspection, an inspection input is applied to the relay from the 1-inspection input application circuit 8 in response to a command issued from the inspection control circuit 9,
Seven differential determination circuits are operated via the VF conversion circuit 2 and the FV conversion circuit 5. However, the FM current differential relay is
Since this is a relay that performs differential determination by transmitting current waveforms at both ends of the power transmission line, if an inspection input is applied during inspection, the inspection input will also operate the relay at the other end. This means that the output of the VF conversion circuit 2 is the output of the FV conversion circuit 5.
This is because, at the same time, the signal is transmitted to the other end through the coupler 6. In this way, the sudden activation of the FM current differential relay at the other end of the electrical station could lead to the breaker on the transmission line mistripping (this indicates the possibility). It is necessary to transmit information that a check input is to be applied to the other end electrical station and perform operations such as locking the output of the FM current differential relay to prevent misrepresentation.As a countermeasure for this, conventional Using a transmission method different from that used by the FM current differential relay, such as a digital transmitter (hereinafter referred to as CDT), "FM current differential relay is being inspected"
It was transmitting signals for inspection markings.

Furthermore, in the FM current differential protection relay system, current waveforms are transmitted to each other using the FM transmission system to perform differential determination.

In this FM transmission system, if a disturbance occurs in the transmission system such as a micro line and an abnormality occurs in the FM carrier wave transmitted from the other end electrical station, the demodulated waveform will be disturbed and the current differential judgment circuit will malfunction. There is a risk that Therefore, receiving F
Measures are taken to lock the current differential judgment circuit when an abnormality is detected by monitoring the M carrier wave verification.

However, frequency deviations in the received signal that occur due to abnormalities in the reference frequency oscillation circuit of radio equipment, especially frequency deviations that fluctuate in AC, are based on the current waveform of the system (frequency changes of the FM carrier wave due to FM modulation and total ( As a result, it is impossible to detect an abnormality in principle, and it is impossible to prevent malfunction of the current differential judgment circuit.As a countermeasure, a pilot signal of a constant frequency is constantly transmitted, and the The current differential determination circuit is locked by detecting alternating current fluctuations in the frequency of the received pilot signal.The above pilot signal transmission method uses a representative channel different from the FM carrier transmission channel. Although there are methods to use this method, the method of transmitting on the same channel is more reliable. Figure 1 shows a method of transmitting the above pilot signals on the same channel, and it includes an oscillation circuit 10, a combining circuit 11, and a coupler. 6 and 4, bandpass filter 12
, an abnormality detection circuit 16, a low-pass filter 14, and a frequency fluctuation detection circuit 15 are provided to detect disturbances in the transmission system.

Note that the above-mentioned FM modulated wave and pilot signal can be easily separated by filters 12 and 14, respectively.

This invention uses the above-mentioned pilot signal to transmit contact information of a differential relay, and it is possible to transmit a signal for inspection marking to the other end electrical station without requiring additional equipment such as a CDT. It is an object of the present invention to provide an FM current differential carrier protection relay device that can perform the following functions.

Hereinafter, a block diagram of an embodiment of the present invention will be described with reference to FIG. 3. 3. The same parts as in Fig. 1 are designated by the same symbols.
In the figure, 18 is a control circuit that controls the oscillation circuit 10 that generates a pilot signal based on inspection input information of the differential relay from the inspection control circuit 9, and 19 is a detection circuit that detects continuous changes in the pilot signal. , 20 are logic circuits that perform logical operations on the output of the abnormality detection circuit 16 and the output of the detection circuit 19.

Next, the operation will be explained. The operation when the differential relay is not inspected is the same as that shown in FIG. 1, but when the inspection signal is applied, the control circuit 18 controls the output signal. This can be done, for example, by stopping the operation of the oscillation circuit 10 and cutting off the pilot signal. If a disconnection is detected, it is possible to obtain inspection information for the sending-side electrical station.

The disconnection of the pilot signal described above can also occur due to an abnormality in the micro line, etc., but in this case, the FM modulated wave is also disconnected, so the abnormality/normality detection circuit 16 that detects the abnormality of the FM modulated wave also operates. Therefore, it is easy to distinguish between this and disconnection of the pilot signal, which indicates that the differential relay at the other end is under inspection.

That is, the logic circuit 20 determines that the differential relay at the other end is under inspection when the abnormality detection circuit 16 that detects an abnormality in the FM modulated wave is inoperative and the pilot signal is disconnected. All you have to do is construct the logic. This can be configured by an inhibit circuit.

As described above, by accurately transmitting a signal indicating that the differential relay at the other end is under inspection, the differential relay at the other end is controlled and its output is locked, thereby preventing malfunction. When the pilot signal is controlled as described above, the pilot signal frequency fluctuation detection circuit 15 does not operate normally, but at this time the output of the differential relay is locked. Therefore, the role of abnormality detection in the transmission system is not required.

In the above embodiment, control 1 of the pilot signal was performed by cutting off the signal, but the frequency of the signal may be changed in a direct current manner. At this time, on the receiving side, the detection circuit 19 detects the DC frequency deviation of the pilot signal.
y11- configuration, and the same effect as in the above embodiment can be obtained. Further, although the above embodiment has a configuration in which the output of the differential relay is locked, a configuration in which the logic sequence section is controlled so that a trip command is not issued from the protective relay device can also produce the same effect as in the above embodiment. .

As described above, according to the present invention, by controlling the pilot signal for detecting an abnormality in the transmission system, information indicating that the differential relay is being inspected can be transmitted. This has the advantage that there is no need to add new equipment.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional FM current differential relay.
FIG. 2 is a diagram showing the frequency relationship between a pilot signal and an FM modulated wave, and FIG. 3 is a block diagram showing an embodiment of the present invention. 10...Oscillation circuit, 11...Synthesizing circuit, 12.14
...filter, 16...abnormality detection circuit, 18...
Control circuit, 19...detection circuit, 20...logic circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa No. 1 Figure Box 2 Figures 3 Figures Procedural Amendment (Voluntary) 1. Indication of the case Japanese Patent Application No. 58-67375 2. Name of the invention FM Core Current Differential Conveyance Protection Relay Device, Amendment Person 5, Detailed explanation of the invention column 6 of the specification to be amended, Contents of the amendment (1) ``Contact information'' on page 6, line 16 of the specification is amended to ``inspection information.'' do. that's all

Claims (1)

[Claims] In an FMM style differential carrier protection relay device which frequency modulates the instantaneous value of the system current of a power transmission line and transmits it between electrical stations, and performs a differential judgment at at least a negative electrical station to protect the transmission line. , an oscillation circuit that generates an FM modulated wave modulated by the system current and a pilot signal that can be separated on the frequency axis, a combining circuit that completely combines the pilot signal and the FM modulated wave, and an FMM flow differential relay. a control circuit that controls the oscillation circuit on condition of inspection;
filters provided separately to separate the M modulated wave and the pilot signal; an abnormality detection circuit that detects an abnormality in the FM modulated wave; and a detection circuit that detects continuous changes in the pilot signal; An FMM flow differential transfer protection relay device comprising a logic circuit that performs a logical operation on the output of the abnormality detection circuit and the output of the detection circuit.