JPH04108337U - Signal terminal equipment for carrier protection relay - Google Patents

Abstract

(57) [Summary] [Purpose] PC for carrier protection relay system using phase comparison method
The purpose is to reliably prevent malfunctions even when signals are exchanged on the M transmission path. [Structure] A malfunction prevention means for a carrier protection relay system is characterized by detecting a frequency shift of a frequency shift signal containing phase information transmitted and received by protection relays at both terminal stations.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention transmits the amount of electricity at each terminal of a power transmission line or the operating status of a relay to the other terminal. The present invention relates to a signal terminal device. In particular, when using PCM carrier terminal equipment on the transmission path, The present invention relates to a receiver for a signal terminal device.

0002

[Conventional technology]

Conventionally, the receiver of this type of signal terminal equipment logically determines the phase information of each of the three phases (A phase, B phase, and C phase) of the power transmission line, and determines whether it is positive, negative, or The receiving circuit 5 includes a receiving circuit 5, a receiving circuit 6, a receiving circuit 7, and a noise detecting circuit 8, which pass any line abnormality to a protective relay. Here, the receiving circuit 5 includes an FS demodulation circuit 51 that frequency-discriminates whether the received input signal is _fH or _fL , a disconnection detection circuit 52 that detects disconnection of the received signal, and a signal from the FS demodulation circuit 51 when determining a line abnormality. and a stabilizing circuit 53 that locks the output regardless of the output. The condition for locking the output is when the disconnection detection circuit 52 or the noise detection circuit 8 that detects noise input from the input terminal 4 outputs an abnormality determination. Receiving circuit 6 and receiving circuit 7 are similar to receiving circuit 5.

0003 In other words, it is transmitted from the signal end station equipment of the other party, and is transmitted from the signal end station equipment, carrier end station equipment, radio equipment, etc. The a-phase FS reception input signal received through the input terminal 1 is inputted from the input terminal 1. input The received FS reception input signal is logically judged by the reception circuit 5, and the result is output to the output terminal 9. Powered. Similarly, the b-phase FS reception input signal is input to input terminal 2, and A logical decision is made in the path 6, and the result is outputted to the output terminal 10. In addition, the c-phase FS receiver The input signal is input to input terminal 3, logically judged by receiving circuit 7, and the result is output. output to power terminal 11.

0004

[Problem that the invention attempts to solve]

Even with such conventional signal terminal equipment, if the transmission path is an FDM carrier device or if the line is It can be used without any problem in a direction comparison type transport protection relay device that requires a slow detection time. However, recently there has been an increase in the number of phase comparison type carrier protection relays, and PCM As more and more transport equipment is used, conventional line abnormality detectors are unable to detect line abnormalities. Regular detection was slow, and there was a high possibility that an erroneous signal would be output from the signal terminal equipment.

FIG. 2 shows the configuration of a recent transportation protection relay system. The conveyance protection relay system determines the fault section by transmitting the amount of electricity at each terminal of the transmission line to be protected or the operating status of the relay to the other terminal via a communication line. For example, the protection relay 12 outputs the positive and negative signals of the commercial frequency in order to monitor the status of the power transmission line (mainly transmission line accidents). The signal end station device 13 converts the positive and negative inputs into FS signals f _H and f _L , and the PCM carrier end station device 14 encodes the FS signals with PCM. Furthermore, the radio device 15 lifts the PCM coded sequence to a radio frequency band, phase modulates it, and sends it out into space.

[0006]The wireless device 15 PCM encodes the phase modulated wave in the radio frequency band from the other party, and the PCM carrier end station device 14 converts the PCM encoded sequence into analog signals f _H and f _L. The signal terminal device 13 outputs analog signals f _H and f _L as positive or negative based on the line abnormality detection result. The protective relay 12 determines the positive and negative conditions together with the state of the power transmission line at its own end, and controls, for example, to open or close a power transmission line breaker. It is important for the signal terminal device 13 to transmit signals accurately, but it is also important to detect line abnormalities at high speed and lock the output so as not to output a faulty signal to the protective relay 12 in the event of a line abnormality. . As described above, PCM carrier terminal equipment and digital radio equipment are often used, and the conventional line abnormality detection circuit has the disadvantage that it is likely to be left unprotected for several milliseconds when a line abnormality occurs.

[0007] This invention alleviates these drawbacks by quickly detecting abnormalities after they occur. It is an object of the present invention to provide a signal terminal device for carrier protection relay having means capable of target

[0008]

[Means to solve the problem]

This invention is designed to reduce the frequency that comes from the signal terminal equipment of the partner station to which the carrier protection relay is connected. A decoder that converts a wave number shift keyed signal into a binary analog signal corresponding to this signal. It is inserted between the demodulating means and the carrier protection relay of its own station, and the above-mentioned binary A carrier equipped with a stabilizing circuit for each phase of the power transmission line that prohibits the passage of analog signals. In the signal terminal equipment for transmission protection relay, the first half of the frequency shift keyed signal is Detects that the time corresponding to the cycle does not belong to the specified range of time, and outputs this detection result. A frequency detection circuit that disables the above-mentioned stabilizing circuit based on the It is characterized by being prepared accordingly.

[0009]

[Effect]

The carrier protection relay system detects abnormalities that occur in the path of signals sent and received between terminal stations. Detects at high speed and locks this signal to the safe side to avoid malfunction of the protective relay.

0010 The present invention is based on the first half cycle of the FS modulated wave containing phase information arriving from the other station. It is determined that the line is abnormal when the time is outside the specified range. This allows for steep reception It can also deal with signal waveform abnormalities, so it can be applied to phase comparison type conveyance protection systems. It is also possible to reliably detect line abnormalities.

[0011]

【Example】

Hereinafter, one embodiment of the present invention will be described based on the drawings. Figure 1 shows the configuration of this embodiment. FIG.

0012 In this embodiment, as shown in Fig. 1, a carrier protective relay is installed for each phase of the power transmission line This transmits frequency shift keyed signals arriving from the signal terminal equipment of the partner station connected to the FS demodulation circuit 51, which is demodulation means for converting the signal into a binary analog signal corresponding to is inserted between this demodulation means and the own station's carrier protection relay, and the binary analog a stabilizing circuit 53 that prohibits the passage of the frequency shift modulated signal; detects that the time corresponding to a half cycle of and a frequency detection circuit 54 that sets the stabilization circuit to an inhibited state based on the output result.

[0013] Next, the operation of this embodiment will be explained based on FIG. Connect the other party's signal terminal to input terminal 1. The FS reception input signal of phase a (one of three phases) of the power transmission line is input from the device. . The FS demodulation circuit 51 converts the FS reception input signal (for example, 2390Hz±400Hz) into_Hkaf_L The disconnection detection circuit 52 detects the disconnection of the received signal, and detects the disconnection of the received signal. It is assumed that there is a line abnormality. The frequency detection circuit 54 monitors the frequency of the received input signal. . In other words, if the half cycle time of the frequency of the received input signal is outside the specified range, (for example, when it is less than 0.15 ms or more than 0.36 ms). The time T from the rise (or fall) of the input signal₁After time T ₂ Create a pulse of width T₂The falling edge of the cycle (or It consists of a logic circuit that monitors whether there is a rising edge or a rising edge. Input terminal 4 The FS reception input signal from the other party's signal terminal equipment does not enter the transmission path (PCM carrier terminal equipment, wireless equipment, etc.). The noise detection circuit 8 monitors this noise, When the noise exceeds a specified value, it is determined that there is a line abnormality. The stabilizing circuit 53 detects disconnection. Line abnormality is detected by any one of the circuit 52, the frequency detection circuit 54, and the noise detection circuit 8. When this occurs, the output of the FS demodulation circuit 51 is locked to the safe side.

[0014] Input terminal 2 receives the b-phase reception input signal sent from the other party's signal terminal equipment. The result is outputted to the output terminal 10 via the receiving circuit 6. Input terminal 3 has a The c-phase reception input signal sent from the signal terminal equipment enters and passes through the reception circuit 7. The result is output to output terminal 11. The receiving circuit 6 and the receiving circuit 7 are both receiving circuits. This circuit is similar to No. 5.

[0015]

[Effect of the idea]

As explained above, the present invention detects a line abnormality in a transmission line by disconnecting the received signal on the own communication line. , since the detection is based on the received signal frequency shift and the noise level on other communication paths. Line abnormality detection can be performed more quickly and reliably than conventional methods. Therefore, it is possible to cope with steep waveform abnormalities of the received signal such as PCM transmission path abnormalities. It is possible to detect line abnormalities in a short period of time, such as a phase comparison type carrier protection relay system. It has a remarkable effect when applied when it is necessary to lock the force.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block configuration diagram showing the configuration of a system to which the embodiment is applied.

FIG. 3 is a block configuration diagram showing the configuration of a conventional example.

[Explanation of symbols]

1~4 Input terminal 5-7 Receiving circuit 8 Noise detection circuit 9-11 Output terminal 12 Protective relay 13 Signal terminal equipment 14 PCM carrier terminal equipment 15 Radio equipment 51 FS demodulation circuit 52 Disconnection detection circuit 53 Stabilization circuit 54 Frequency detection circuit

Claims (1)

[Scope of utility model registration request] 1. Demodulating means (51) for converting a frequency shift keyed signal arriving from a signal end station device of a partner station connected to a carrier protection relay into a binary analog signal corresponding to this signal; A carrier protection relay is inserted between the demodulation means and the carrier protection relay of its own station, and is provided with a stabilizing circuit (53) for prohibiting passage of the binary analog signal, corresponding to each phase of the power transmission line. The electrical signal terminal equipment detects that the time corresponding to the first half cycle of the frequency shift modulated signal does not belong to the specified time range, and based on this detection result, sets the stabilization circuit to a disabled state. A signal terminal device for carrier protection relay, characterized in that it is equipped with a frequency detection circuit (54) corresponding to each phase of a power transmission line.