JPH02179221A - Sampling synchronous system for loop digital protective relay - Google Patents

Abstract

PURPOSE:To enable obtaining sampling data at the same time from respective terminal equipments by transmitting a code signal for each terminal equipment from a central relay apparatus, by computing the transmission delay time of each terminal through a return signal from each terminal and by outputting a signal expecting said transmission delay time from said central relay apparatus. CONSTITUTION:A signal coded for each terminal 8-1 to 8-3 is sent from the synchronous arithmetic circuit 4-1 in a central relay apparatus 1 to terminals 8-1 to 8-3 via an optical fiber cable(OFC) 9. The folded circuits 4-2 to 4-4 of respective terminals 8-1 to 8-3 fold only sampling signals attached with their own codes by transmitting said signals to the apparatus 1 via the OFC 10. The transmission delay time to each terminal 8-1 to 8-3 is obtained by said apparatus 1 and said sampling signal is outputted to each terminal 8-1 to 8-3 at any point of time after generation of a reference pulse and before the transmission delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a data sampling synchronization system for a digital protection relay device for protecting a loop power transmission system.

B6 Summary of the Invention The present invention is a data sampling synchronization system for a digital protective relay device placed in a loop power transmission system, in which a central relay device transmits a signal with a code attached to each terminal device to each terminal device. , each terminal device loops back the signal of its own code to the central relay device, calculates the transmission delay time for each terminal device based on the loopback signal, and samples the signal from the central relay device at a time that takes into account the transmission delay time. By outputting signals, each device can obtain sampled data at the same time, and the central relay device can process these data without time errors, making the digital protection relay device as a whole extremely error-prone. This results in a system with high judgment accuracy.

C1 Prior Art FIG. 5 shows a system configuration diagram of a loop-shaped digital protection relay device that protects a loop-shaped power transmission line.

In the figure, the substation U and the busbars 31 of four customers D1 to D4 are connected in a loop by a power transmission line 32, and each customer D1 to D4 has a transformer installed at the terminal of the power transmission line 32. 34, a terminal device 35 that inputs analog data from the current transformer 34, converts it into an optical signal, and sends/receives the signal to neighboring consumers, and a circuit breaker 36 that cuts off the bus 31 from the grid. In addition, within the substation U, there is a central communication device 37 which has the same function as the terminal device 35, a function to convert optical signals into digital data, and analyzes and processes the data. In this case, a central relay device 38 consisting of a microcomputer or the like outputs a command to shut off the circuit breaker 36 to the terminal device 35 in each customer through the central communication device 37, and analog data is directly sent to the central relay device 38. and a current transformer 34 for input. Further, each terminal device 35, the central communication device 37, and the central relay device 38 are connected by an optical fiber cable 39, and this optical fiber cable 39 receives the optical signal output from the terminal device 35 in each customer, and the central relay device 38. This becomes a path for an optical signal as a cutoff command outputted from 38.

In a loop-shaped digital protection relay device with such a system configuration, analog data collection (hereinafter referred to as sampling) from the terminal devices 38 in each customer and data transmission to the central relay device 38 are performed by the central relay device. This is done using the sampling signal output from the. This sampling signal is an optical signal output at a certain frequency that takes into consideration the data transmission speed in the system, the memory capacity and processing speed of the microcomputer in the central relay device, and is connected to the optical fiber cable 39 described above. The data is transmitted to each customer's terminal device via the terminal device.

However, since a transmission delay occurs while this sampling signal is transmitted through the optical fiber cable and within each terminal device 35, the sampling of each terminal device 35 and the central relay device 38 is not performed at the same time, and the central relay device 38 is not sampled at the same time. The further the terminal device (in this case, D) is from the terminal, the larger the sampling delay will be. Furthermore, if a portion of the optical fiber cable is damaged and the optical signal is loopback transmitted, the optical transmission path will become even longer, and the sampling delay may double compared to normal times.

Therefore, the sampling synchronization method of the conventional loop-shaped protective relay device employs a transmission delay fixed compensation method that takes the above-mentioned transmission delay into consideration. That is, as shown in the time chart of FIG. 6, the central relay device 38 has its own sampling time t.

A sampling signal is transmitted to the central communication device 37 one hour in advance based on . The sampling signal is a flag (F)
and a sampling synchronization command (S), and a flag (F
) is transmitted, and after a certain period of time has elapsed, a sampling synchronization command (S) is transmitted.

The central communication device 37 further transmits the transmitted sampling signal to the subsequent customer DI terminal device.

Each terminal device waits for sampling when the flag (F) arrives, and performs sampling sequentially at times t1, t5, and t4 when the sampling synchronization command CS') arrives. I do. In this way, in this method, the central relay device 38 transmits the sampling signal to each terminal device one hour in advance, taking into account the transmission delay to each terminal device 35, thereby determining the sampling time of the central relay device. Based on the standard, it can be set so that all terminal devices complete sampling within the sampling permissible time limit T'.

Incidentally, the allowable limit time T' is determined based on the fault determination accuracy of the protective relay device, and is usually a value of several AC electrical angles.

D0 Problems to be Solved by the Invention However, in the above-mentioned fixed transmission delay compensation system, although the terminal equipment of each consumer is set to complete sampling within a predetermined time, the transmission delay cannot be removed in principle. Therefore, even if the transmission system is normal, there is a time error in the sampling data obtained, and if the transmission system is long, the sampling signal may be transmitted in a loopback due to a defect in the optical fiber cable, etc. Under such conditions, the transmission delay becomes extremely large, so in such cases, the allowable limit time T' must be set large, and this causes the problem that the fault judgment accuracy of the entire protective relay device deteriorates. there were.

The present invention has been made in view of the above, and its purpose is to enable data sampling in the central relay device and each customer terminal device to be performed at the same time, and to The aim is to provide a sampling synchronization system with high accuracy in accident determination.

E2 Means for Solving Problems The present invention provides that the central relay device includes an output section that outputs a sampling signal attached with a code corresponding to each terminal device, and an output section that outputs a sampling signal attached with a code corresponding to each terminal device, and an output section that outputs a sampling signal with a code corresponding to each terminal device. a timer section that measures the time T' until the code is turned around and returned by the code; a reference pulse generation section that generates a reference pulse at a period T0; ('r0-'r'/2)='r
and a sampling signal control section configured to output a sampling signal with a corresponding code after the time T calculated by the calculation section has elapsed since the generation of the reference pulse. The terminal device has
The terminal circuit is characterized in that, when receiving a sampling signal to which a self-code corresponding to the terminal device is attached, a folding section is provided for folding back the sampling signal, and the terminal circuit performs sampling using the sampling signal to which the own code is attached. .

The F3 acting central relay device outputs a sampling signal with a code attached thereto, and the terminal device loops back the sampling signal attached with its own code. The central relay device measures the round-trip time required for the sampling signal for each code, calculates the one-way time required, which is half of it, and outputs the sampling signal in consideration of this time.

As a result, the timing of sampling becomes the same between the central relay device and the terminal devices.

G. Example The present invention will be explained in detail below based on examples.

FIG. 1 is a configuration diagram of a sampling synchronization system for a loop-shaped protective relay device showing an embodiment of the present invention.

In the figure, l indicates a central relay device, and 8-1 to 83 indicate terminal devices of each customer. The central relay device 1 includes an information processing device 2 consisting of a microcomputer that processes digital information, synchronous calculation circuits 4-1 and 4-5, and a reference sampling signal to the synchronous calculation circuits 4-1 and 4-5. The output reference pulse generator 3 and the electro-optical converter (hereinafter E10)
) 5-1.5-8 and electric-optical converter (hereinafter referred to as 0/E) 6-
1.6-8. In addition, each terminal device 8-1~
8-3 are terminal circuits 7-1 to 7-3 that collect and digitize analog data, and return circuits 4-2 to 4-4.
and E105-2 to 5-7.0/E 6-2 to 6-7, respectively.

Opposing Elo and O/E of adjacent devices are connected by optical fiber cables 9 and IO, respectively, as shown in the figure.

The synchronization calculation circuits 4-1 and 4-5 have a function of calculating the transmission delay time for each terminal device and controlling the output timing of the sampling signal based on the transmission delay time. When this circuit is shown in FIG. 2, 22 is an output circuit for outputting sampling signals to each terminal device. By the way, the central relay device l and each terminal device 8-1 to 8-
Information sampled from 3 and central UI! ! Command information from device l to each terminal device is CMI (Coda
(Mirked Inversion) code and transmitted via optical fiber cable 9 or 10.

Therefore, as a sampling signal, a CRV (C
ode-rzr Ru1e Vlolatlon)
Using a functional CRV pulse, this CRV pulse is converted into a conid for each terminal device and extracted into the CMI code string of main data. Therefore, the output circuit 22 outputs a sampling signal having a code corresponding to each terminal device.

In connection with the circuit shown in FIG. 2, each terminal device 8-1
Folding circuits 4-2 to 4 provided in ~8-3, respectively
Regarding the function 4, each folding circuit returns, among the sent sampling signals, a sampling signal having a code corresponding to the terminal device including the folding circuit to the central relay device I. It has a function to send other sampling signals to the lower-order terminal device.

Returning to the circuit shown in FIG. 2, 23 in FIG. 2 is a receiving circuit that receives sampling signals returned from each terminal device, and A, -A are timer circuits. The timer circuits A + -A s are provided corresponding to the terminal devices 8-1 to 8-3, respectively, and are activated when the code-specific sampling signal is output from the output circuit 22, and when the code-specific sampling signal from the receiving circuit 23 is output. A time-up occurs when receiving the sampling signal. Therefore, the time T' measured by each timer circuit A, -A, corresponds to the round trip time of the signal to the terminal devices 8-1 to 8-3, respectively. B, -B3 are arithmetic circuits which perform a calculation to subtract the time value 172 obtained by each timer circuit A, -AI from the period T0 of the reference pulse from the reference pulse generator 3. 24 is a sampling signal control circuit, and the calculation result 'r= (TO-
The output of the sampling signal is controlled based on T'/2) and the reference pulse.

Next, the operation of the above embodiment will be described with reference to FIG. FIG. 3 is a diagram conceptually showing the operation of the embodiment, with the vertical direction representing the flow of time and the horizontal direction representing the length of the signal path from the central relay device.

The reference pulse generator 3 in the central relay device 1 generates reference pulses at time intervals of the sampling reference time T0, and when the synchronization calculation circuit 4-1 receives this pulse, the 4-1 sends a signal to the information processing device 2. Outputs a sampling command to sample signals from the grid. At the same time, the synchronous calculation circuit 4
-1 output circuit 22 (see FIG. 2) outputs a sampling signal with a code attached for each terminal device. This sampling signal is sent to each terminal device 8-1 to 8-3 via the optical fiber cable 9, and is sent to each terminal device 8-1 to 8-3.
3, only the sampling signal with its own code is returned by the return circuit and transmitted to the central relay device 1 through the optical fiber cable IO, while the other sampling signals are sent as they are to the lower side. In this way, when the sampling signal is turned back from each terminal device 8-1 to 8-3 and returned to the central relay device I, the timer circuit A is activated.

~A, the times T1~T required for the signal to travel back and forth to the terminal devices 8-1~8-3, respectively, are determined. The portion shown as an asynchronous state in FIG. 3 shows how such signals are folded back. Next, the above T and -'rs are each 1/2
The one-way time, that is, the transmission delay time, to each terminal device is determined by determining the magnitude of the signal, and the sampling signal is outputted to each terminal device at a time point before the transmission delay time from the time point at which the reference pulse is generated. This action is first caused by the arithmetic circuits B1 to B,
, the period of the reference pulse is To, and ('ro-T
+tt), (To Tttt>, (Ta T'3
zt) is executed, and the control circuit 24 delays the calculation result time from the input of the reference pulse, and then outputs the terminal device 8 to each terminal device 8.
This is achieved by outputting sampling signals from the output circuit 22 to the signals 1 to 8-3. For example, after the reference pulse is generated, the terminal device S
A sampling signal is output at -t. As a result, as shown in the lower part of FIG. 3, since the sampling signals are received at the same time at each terminal device 8-1 to 8-3, the central relay device 1 performs sampling in synchronization with the reference pulse. As a result, each terminal circuit 7-1 to 7-3 performs sampling in synchronization with the sampling signal of its own code, so that sampling is synchronized between the central relay device and each terminal device. As mentioned above, the sampling command is sent to the central relay device 1, the terminal devices 8-1, 8-2.
8-3, there is no need for the synchronous calculation circuit 4-5 in the central relay device (2) to function at all.

Next, the operation of the sampling synchronization system in the case where the optical fiber cable is damaged for some reason and the loop-shaped digital relay device has a loopback function will be explained based on FIG.

The figure shows a case where the optical fiber cable between terminal devices 8-2 and 8-3 is damaged, but at the same time this relay device starts the loopback function, the synchronous calculation circuit in the central relay device l While making 4-5 function, the terminal device 8-
In the synchronous arithmetic circuit 4-4 in 3, the function of the input/output terminal is changed when no loopback operation is performed, and further in 6-7.
．． Convert 6-8 to E10, and convert 5-7.5-8 to 0/E.

Thereafter, the transmission delay time is determined in the same manner by the synchronization calculation circuit 4-5 and the return circuit 4-4, and the sampling is synchronized.

As described in detail in the H8 invention, in the present invention, a synchronous calculation circuit is provided inside the central relay device, and the synchronous calculation circuit calculates the round-trip time of the signal to each terminal device, and calculates the sampling signal for each device. The transmission delay time of is calculated, and data is transmitted from the central relay device to the terminal devices taking into consideration each transmission delay time, so the central relay device and each terminal device can always sample data at the same time. This is exactly the same even in the case of loopback transmission, so that the information processing device in the central relay device can process sampling data without time errors. Therefore, the loop-shaped digital protective relay device can constitute a system with extremely high accident determination accuracy as a whole.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the entire embodiment of the present invention, Fig. 2 is a block diagram showing a part of the synchronous calculation circuit, Fig. 3 is an explanatory diagram showing the operation of the present invention, and Fig. 4 is a loopback diagram. FIG. 5 is a block diagram showing a system for transmission, FIG. 5 is a block diagram showing a system of a conventional loop protective relay device, and FIG. 6 is a chart showing the operation of a conventional sampling synchronization method. ! ...Central relay device, 2...Information processing device, 3...
・Reference pulse generator, 4-1, 4-5...Synchronous calculation circuit, 4-2 to 4-4...Return circuit, 7-1 to 7-
3... Terminal circuit, 8-1 to 8-3... Terminal device, 9
．． 10...Optical fiber cable. Figure 2: Part of the prog diagram of the synchronous Hama'X circuit. B+~Bx・-111JIIu circuit Fig. 3 Functional diagram of the embodiment

Claims (1)

[Claims] (1) A central relay device and a plurality of terminal devices having terminal circuits for signal collection are connected in a loop via a cable, and the central relay device In a device that performs sampling in electrical equipment and terminal equipment, the central relay equipment includes an output unit that outputs a sampling signal with a code corresponding to each terminal equipment, and a terminal unit that outputs a sampling signal with a code corresponding to each terminal equipment. A timer section that measures the time T' until the device turns back and returns for each code, a reference pulse generation section that generates a reference pulse at a cycle T_0, (T_0-T'/2)
=T, and a sampling signal control section that controls the output of sampling signals with respective corresponding codes after the time T calculated by the calculation section has elapsed since the generation of the reference pulse. , the terminal device is provided with a folding unit that folds back the sampling signal when receiving the sampling signal attached with the own code corresponding to the terminal device, and the terminal circuit performs sampling using the sampling signal attached with the own code. A sampling synchronization system for a loop-shaped digital protective relay device characterized by performing the following.