JPH0515549U - Transmission system test equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To facilitate transmission system testing in a short time. [Configuration] In a protective relay system for protecting a power system by transmitting a monitoring / control signal of a power system by coupling a plurality of terminal devices and the central communication device with a transmission cable, the terminal device and the central communication device are A test signal transmission circuit (39) for a transmission cable test, a reception circuit (38) for measuring an error rate of a reception signal passed through the transmission cable, and control from a central communication device side or a terminal device side And a switching unit (37A, 37B) for switching the test signal from the transmission circuit onto the transmission cable and loading the reception signal passed through the cable into the reception circuit. Conduct a transmission cable test between devices or between a central communication device and a terminal device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a test device for an inter-device transmission system in a power system protection relay system.

[0002]

[Prior Art]

In the power system protection relay system, for example, in the loop line system, inter-node coupling is performed by the loop transmission line shown in FIG. In the figure, in contrast to the loop line system that connects the substation bus 1 to a plurality of customer buses 2 ₁ to 2 _n with the loop line 3, the protective relay system has the central communication device 4 on the substation side and the customer side. The terminal devices 5 _{1 to} 5 _n are provided in the terminal, and the loop control path 6 formed by the composite optical cable connects the terminal devices to each other to transmit the monitor control information.

The loop transmission line 6 is a duplex loop system in which information is transmitted clockwise and counterclockwise between the respective terminal devices 5 _{1 to} 5 _n , and a communication function is secured even in the case of a disconnection failure of the transmission line or the like. This communication involves monitoring and transmitting control information on the customer side.

The central communication device 4 gives information about the terminal device to the central relay device 7, and also transfers information between the concentrator 8 and the power feeding station 9. The central relay device 7 transmits and receives protection information to and from the switchboard 10 on the substation side to protect the grid. Further, it has a communication function to the master station 12 of the general control station via the slave station 11.

In the protective relay system as described above, the loop transmission line 6 connecting the terminal devices 5 _{1 to} 5 _n and the central communication device 4 is provided with an optical cable of a regular system and a loopback system for duplication. Besides, it is made into a composite optical cable in which a spare cable, a consumer cable, and a telephone line are collectively stored, for example, a 24-core optical cable and a telephone line.

Here, when a disconnection or a signal abnormality occurs in the transmission line 6 or during maintenance / inspection, a dedicated measuring instrument is used between the terminal devices or between the central communication device 4 and the terminal device separately from the system. The test is being done. FIG. 3 shows a conventional test apparatus, which is shown in the case of a transmission line test between terminal devices 5 _k and 5 _k-1 . For the loopback transmission line test from the terminal device 5 _k to 5 _k-1 , the optical cable is disconnected from the transmission line 6, and the transmitter 21 of the error rate testing device is prepared on the side of the terminal device 5 k. The simulated transmission signal (pulse train signal) from 21 is put on the loopback type optical cable, and this signal is received by the receiver 22 of the error rate tester prepared on the terminal device 5 _{k- 1} side, and the error rate is calculated from this received signal. By measuring, the normal / abnormal condition of the loopback optical cable between the terminal equipment _5k and _5k-1 can be determined and the cause of the abnormality can be investigated.

[0007]

[Problems to be solved by the device]

 The conventional test equipment requires a transmitter 21 and a receiver 22 for measuring the error rate, and these need to be connected to the cable to be tested at the site where the terminal equipment is installed. Also, to connect the transmitter 21 and the receiver 22 to the cable, all the cables of the transmission line are disconnected by the optical permanent connection box, and the terminal equipment at both ends of the cable to be tested is disconnected from the central communication equipment. , It will stop functioning for a long time.

An object of the present invention is to provide a transmission system test device that facilitates a test of a transmission system in a short time.

[0009]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a protection relay system in which a plurality of terminal devices and a central communication device are connected by a transmission cable, and a power system is protected by transmitting and receiving a supervisory control signal. The communication device includes a transmission circuit that generates a test signal of a transmission cable, a reception circuit that measures an error rate of a reception signal that has passed through the transmission cable, and control from the central communication device side or terminal device side control. According to the present invention, there is provided switching means for loading the test signal from the transmission circuit on the transmission cable and taking in the test signal via the transmission cable to the reception circuit.

[0010]

With the above structure, a test signal is transmitted from the transmission circuit of the terminal device or the central communication device, which is one end of the transmission cable, which couples the central communication device and the plurality of terminal devices, and the signal is transmitted to the transmission cable. The signal is received by the receiving circuit of the terminal device or central communication device at the other end of the, and the transmission cable is tested by measuring its error rate. In this test, the transmission cable can be connected to the transmitting circuit and the receiving circuit under the control of the central communication equipment.

[0011]

【Example】

 FIG. 1 is a circuit diagram of an essential part showing an embodiment of the present invention. The terminal devices 31, 32 correspond to the terminal device or the central communication device of FIG. 2 or 3, and are connected to each other by a duplex optical cable (only one cable is shown in the figure) 33. Each of the terminal devices 31 and 32 converts an optical reception signal from the cable into an electric signal by the optical receiver 34, converts an electric signal from the signal processing circuit 36 into an optical signal by the optical transmitter 35, and outputs the electric signal to the cable 33. Optical transmission is performed. The signal processing circuit 36 mainly performs monitoring signal transmission processing and control signal reception processing.

Here, in the present embodiment, changeover switches 37A and 37B are provided in the connection between the signal processing circuit 36 and the optical transmitter 34 and the optical receiver 35. The changeover switch 37A switches the signal received by the optical receiver 34 to the signal processing circuit 36 and the receiving circuit 38 for the error rate test and gives it. The changeover switch 37B switches the transmission signal of the optical transmitter 35 between the signal processing circuit 36 and the error rate test transmission circuit 39.

The error rate test transmission circuit 39 and the reception circuit 38 have the same functions as those of a conventional error rate test apparatus, and perform pulse train transmission for error rate testing and error rate measurement by receiving the pulse train signal. Therefore, the optical cable 33 is judged to be normal or abnormal.

In this embodiment, the changeover switches 37A and 37B are normally switched to the illustrated state, and the optical reception signal from the optical cable 33 is taken into the signal processing circuit 36 through the optical receiver 34, and the signal processing circuit 36 is received. The transmission signal from 36 is sent to the optical cable 33 via the optical transmitter 35.

Next, in the error rate test of the optical cable, that is, the optical cable test between the terminal devices 31 and 32, the changeover switch 37B of the terminal device 31 side is changed over to the transmitting circuit 39 side, and the changeover switch 37A of the terminal device 32 side. Is switched to the receiving circuit 38 side, the test signal from the transmitting circuit 39 of the terminal device 31 is transmitted to the receiving circuit 38 of the terminal device 32 via the optical transmitter 35, the optical cable 33 and the optical receiver 34, and the optical cable 33 between them is transmitted. Error rate test is performed.

Here, the changeover switches 37A and 37B are changed over by the control signal transmission from the central communication device 4 side in addition to the changeover at the site where the terminal devices 31 and 32 are installed. This signal transmission is performed as a control command to the signal processing circuit 36 using one of the duplex optical cables. Also, the error rate measurement result data is transmitted from the terminal device to the central communication device side.

Therefore, the error rate test of the optical cable between the terminal equipment or the optical cable between the central communication equipment and the terminal equipment is carried out by transmitting a test control signal from the central equipment side and receiving the error rate measurement result, which is the same as in the conventional field. There is no need to go to the test to make the test quick and easy, and the monitoring and control functions of the terminal equipment at both ends of the optical cable to be tested are not lost.

In the embodiment, the transmitting circuit 38 and the receiving circuit 39 for the error rate test are shown separately from the signal processing circuit 36. However, the hardware for giving the signal processing circuit 36 the functions of these transmitting circuit and receiving circuit. It can be a hardware configuration or a software configuration. Similarly, the changeover switches 37A and 37B can be provided with a changeover function in software.

In addition, although the embodiment shows the case of applying to a system using a loop type duplex optical cable as a transmission line, a system having a transmission line that does not form a loop, a transmission line of one line, and a transmission line of an electric signal line configuration. Can be applied to. In the case of one line, the transmission and reception to both sides of the cable to be tested can be realized by loop transmission or by transmitting the test control signal and receiving the measured value using a telephone line.

[0020]

[Effect of the device]

 As described above, according to the present invention, each terminal device and the central communication device respectively have a test signal transmitting circuit, a receiving circuit for measuring an error rate, and a test signal from the transmitting circuit to a transmission cable for testing. The following effects are obtained because the configuration is provided with switching means for loading this signal into the receiving circuit, and switching by the switching means is performed from the central communication device side or the terminal device side.

(1) It is not always necessary to go to the site for the test, and the remote test can be performed by the control of the central communication device side.

(2) The work of connecting / disconnecting the measuring device and the cable for the test is unnecessary.

(3) The conventional transmitter, the transmitter equivalent to the receiver, the receiver, and the switching means can be provided to the signal processing circuit of the terminal device or the like as a function, without complicating the system. ..

(4) Since the central communication device and the terminal device each have a transmission circuit and a reception circuit, it is possible to quickly determine an abnormal section when a transmission abnormality occurs.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an essential part showing an embodiment of the present invention.

FIG. 2 is a block diagram of a protective relay system.

FIG. 3 is a circuit diagram of a conventional test apparatus.

[Explanation of symbols]

3 ... ring line system line, 4 ... central communication unit, 5 _1, 5 _n ... terminal device, 6 ... optical cable, 31, 32 ... terminal device, 3
3 ... Optical cable, 34 ... Optical receiver, 35 ... Optical transmitter, 3
6 ... Signal processing circuit, 37A, 37B ... Changeover switch, 3
8 ... Transmitting circuit, 39 ... Receiving circuit.

Claims (1)

[Scope of utility model registration request] 1. A protection relay system in which a plurality of terminal devices and a central communication device are connected by a transmission cable, and a power system is protected by transmitting and receiving a supervisory control signal, wherein the terminal device and the central communication device respectively perform transmission. A transmission circuit for generating a cable test signal, a reception circuit for measuring an error rate of a reception signal passing through the transmission cable, and a test from the transmission circuit under the control of the central communication device side or the terminal device side. A test device for a transmission system, comprising: switching means for loading a signal on the transmission cable and taking in the test signal via the transmission cable to the receiving circuit.