JPH0254011B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a recirculation system that automatically recloses line breakers and disconnectors that have been opened due to an accident on a power transmission line in a power system, depending on various conditions. The present invention relates to a circuit-closing device, and more particularly, to a monitoring method for a voltage detection circuit that detects bus voltage and line voltage for re-closing.

[Technical background of the invention]

When an accident occurs on a power transmission line, the accident is usually detected by a line protection relay device, and the detection signal is used to issue a control command to the circuit breaker control device to open the circuit breaker. The circuit breaker opened in this way is then closed to improve the stability of the power system.
It is necessary to restore the grid to its original state. A reclosing device performs this restoration operation quickly, accurately, and automatically. The reclosing device is activated by the output signal of the relay element that operates when the protective relay device detects an accident, and after a certain period of time, confirms the conditions for reclosing and issues a closing command to the circuit breaker.

The conditions for closing a line breaker using a reclosing device are as follows:
For example, the presence or absence of voltage on the power transmission line side and the bus line side and the synchronization state are determined by guiding the line voltage and the bus line voltage taken out through the respective voltage transformers to a detection circuit within the device.

[Problems with background technology]

Since the reclosing device operates only in the event of a system fault,
To check whether the voltage detector operates normally, you can perform a simulation test by giving the voltage detector a simulated input from periodic inspections, or if you want to perform constant monitoring, you can duplicate the detection unit. Either one of these methods was adopted, and the status was monitored by comparing the outputs of each. However, in the former case, since constant monitoring is not possible, it is discovered during periodic inspections or due to malfunctions such as system accidents, and there is also a problem in the reliability of the device. In addition, the latter method requires duplication, so two sets of the same voltage detector are required, which leads to a rise in price, and the number of parts increases, making it difficult to improve the reliability of the device as a whole. But it was a drawback.

[Purpose of the invention]

The present invention was developed in view of the above circumstances, and it enables easy constant monitoring using a digital voltage detector, and also provides a highly reliable reclosing device with a reduced number of circuit components. The purpose is to provide.

[Summary of the invention]

The reclosing device of the present invention constantly monitors that the difference in the amount of electricity output from the bus voltage detection section and the line voltage detection section is within a certain range under the condition that the line breaker is closed. be.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an example of application of the reclosing device of the present invention. 1 is a bus bar, and the bus voltage is detected by bus bar PT2. Reference numeral 3 denotes a disconnector that connects the power transmission line 5 to the bus bar 1, and is turned on or off by a control circuit 7, which will be described later. 4 is a CT for railway lines, and Arashiya disconnector 3
It is installed on the track 5 side. 6 is for railroad tracks
PT, and is installed so as to detect the voltage on the line 5 side rather than the breaker 3. 8 is a protective relay device that determines whether or not an accident has occurred in the power transmission line 5 based on the voltage and current from the PT 6 and CT 4, and when it is determined that an accident has occurred, provides the output signal to the control circuit 7. Pull out the disconnector 3. Reference numeral 9 denotes a reclosing device, which includes an external input receiving circuit 10, a digital bus voltage detection circuit 11, a digital line voltage detection circuit 12, a synchronization detection circuit 13 for detecting synchronization of line voltage and bus voltage, and a microprocessor. It consists of a sequence processing section 14 made up of a setter and an output circuit 15. When the external input receiving circuit 10 receives the output signal of the protective relay device 8, it receives this as a starting command. As a result, the sequence processing unit 14 is activated, and after a predetermined time period, the bus voltage detection circuit 11 detects the voltage of the bus PT2, the line voltage detection circuit 12 detects the voltage of the line PT6, and the conditions of PT2 and PT6. The re-closing condition is confirmed by the detection output of the synchronization detection circuit 13 which detects the phase difference based on Let's do it. Needless to say, the importance of the bus voltage detection circuit 11, line voltage detection circuit 12, and synchronization detection circuit 13, which detect the reclosing conditions for safely restoring the system connection, is important.

Next, the voltage monitoring procedure of the sequence control section 14 will be explained with reference to the flowchart of FIG.

The conditions for the line breaker 3 are input to the control circuit and the external input receiving circuit 10, and it is determined whether the circuit is open or closed in the line breaker condition judgment step 21. If YES, the bus voltage detection circuit 12 and the line The detected values V _B and V _L of the voltage detection section 13 are read in step 22 .
If no, proceed to the end. Voltage difference between the detected values read in the voltage input step 22 |V _B −V _L
| is determined in the differential voltage calculation step 23. A difference voltage determination step 24 determines whether the value obtained in the differential voltage calculation step 23 is within a predetermined value (reference value: X), and the differential voltage determination step 2
If the value determined in step 4 is larger than the reference value (if the inequality does not hold), a detection failure processing step 25 outputs an alarm to the outside.

〔Effect of the invention〕

As described above, according to the present invention, when the breaker is in a closed state, the bus voltage and line voltage connected by the breaker can be detected within the range of the reference value. It is possible to provide a reclosing device that can immediately detect a defect in the detection unit no matter how the system voltage changes.

[Brief explanation of the drawing]

Figure 1 shows a power distribution diagram to which a reclosing device is applied;
FIG. 2 is a flowchart showing a method for detecting a differential voltage failure between a bus voltage and a line voltage of a reclosing device. 1... bus bar, 2... bus bar PT, 3... bow breaker,
4... Track CT, 5... Track, 6... Track PT, 7
... Control circuit, 8 ... Protective relay device, 9 ... Reclosing device, 10 ... External input receiving circuit, 11 ... Bus voltage detection circuit, 12 ... Line voltage detection circuit, 1
3... Synchronization detection circuit, 14... Sequence processing unit, 15... Output circuit, 21... Shrink breaker condition determination step, 22... Voltage input step, 23...
...Difference voltage calculation step, 24...Difference voltage determination step, 25...Detection failure processing step.

Claims (1)

[Claims] 1. A re-closing device that operates during a power system fault and issues a closing command to a power line breaker based on a system voltage status detection signal obtained from a voltage detector that detects the state of the line voltage and bus voltage of an opened power line breaker. In the
When the line breakers provided at each terminal of the power system are turned on, the output values of the line voltage detector and the bus voltage detector are compared and the line voltage is detected on the condition that the voltages at both ends are approximately equal. A reclosing device characterized in that a busbar voltage detector and a busbar voltage detector are constantly monitored.