JPH02108981A - Automatic monitor device for gapless arrester - Google Patents

Abstract

PURPOSE:To monitor the deterioration and life of a lightning rod securely and automatically by deciding the deterioration, thermal stability, and processing energy of the lightning rod as to a leak current or power loss. CONSTITUTION:The arrester 2 is connected to a system bus 1 and its voltage is detected by a voltage detector 3; and the low-voltage side operation counter 4 of the arrester 2 detects the number of times of arrester operation as the number of times of the making of the contact and a current transformer 5 detects the current of the arrester 2. A measuring circuit 6 measures the leak current I or finds the power loss W of the arrester 2 from the detected current I from the current transformer 5 or the detected voltage V of the detector 3. Then the monitor device 7 detects whether or not there is the deterioration due to the current I when the output contact of the counter 4 is off and the voltage V is normal at the time of the measurement of the current I and also decides that the current I or loss W is caused by the voltage V if the voltage V is abnormal when the output contact is on. The decided current I or loss W is used to decide the stability and processing energy of the arrester 2.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an automatic monitoring device for gapless surge arresters.

B1 Summary of the Invention The present invention automatically monitors the deterioration and lifespan of a lightning arrester by determining deterioration and thermal stability of the leakage current or power loss of the lightning arrester based on the presence or absence of lightning protection operation and the normal/abnormal condition of the system bus voltage. By making energy judgments, it is possible to reliably monitor the deterioration and lifespan of lightning arresters, and also to monitor the extent of such deterioration.

C1 Conventional technology A lightning arrester with a non-linear resistor mainly composed of zinc oxide and a no-gap lightning arrester will cause an increase in leakage current for the same applied voltage as it deteriorates due to surge energy absorption due to lightning protection operation or aging. , thermal instability occurs due to increased power loss, leading to the end of its life.

The heat balance of this lightning arrester is as shown in FIG. 3, and the heat dissipation characteristic A is determined by the structure of the insulator tube that houses the lightning arrester, and the amount of heat dissipation becomes saturated as the ambient temperature rises. On the other hand, the heat generation characteristic B is the heat generation performance of the lightning arrester element, and the amount of heat generated increases exponentially as the ambient temperature rises. In heat generation characteristic B, as the deterioration of the element progresses, the amount of heat generated increases as shown in characteristic B'. If this heat generation characteristic B is in a lower range than the heat radiation characteristic A, it is thermally stable, and it can be said that the lifetime of the lightning arrester is maintained thermally stable as long as it absorbs the specified surge energy.

Conventionally, as automatic lightning arrester monitoring devices, methods are known that record the number of lightning arrester operations by absorbing surge energy, record discharge current values with a current recorder, and measure leakage current.

D0 Problems to be Solved by the Invention In conventional automatic monitoring devices, deterioration and lifespan can be determined by recording the number of operations. Although it is possible to monitor the number of operations and operation time online, it is difficult to determine the number of surges because the size of the surge is not known. There was a problem in that it was difficult to determine the reliability of deterioration and lifespan because there was no correlation between lifespans.

On the other hand, determination by current recording can record the magnitude of the surge, but it is difficult to record multiple operations, making it difficult to make reliable determinations like the above-mentioned method.

In addition, although thermal stability can be directly monitored online when making a judgment based on leakage current measurement, it is not possible to judge whether the increase in current is due to surge absorption, deterioration, or abnormality in the grid voltage, so it is difficult to judge Sometimes I do.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic monitoring device that can reliably and automatically monitor the deterioration and life span of a lightning arrester.

81 Means and Effects for Solving the Problems In order to achieve the above object, the present invention provides an operation counter that obtains the number of lightning arrester operations using an output ON signal, a current transformer that detects the current of the lightning arrester, and a lightning arrester connected to each other. a voltage detector that detects the voltage of the system bus bar to be operated; a measurement circuit that measures the leakage current or power loss of the lightning arrester from the detected current of the current transformer and the detected voltage of the voltage detector; means for determining deterioration of the lightning arrester with respect to the leakage current or power loss when the lightning arrester is in a detection state that the lightning arrester is not in operation and the voltage detector is in the normal detection state of the grid voltage; a monitoring device having means for determining the thermal stability of the lightning arrester from the time rate of change of the leakage current or power loss when the voltage detector is in an abnormality detection state of the system voltage and means for determining the processing energy; Regarding lightning arrester leakage current or power loss, reliable judgment and extent judgment can be obtained by distinguishing between deterioration judgment, thermal stability, and processing energy judgment based on the presence or absence of lightning arrester operation and whether the system voltage is normal or abnormal.

F. Embodiment FIG. 1 is an apparatus configuration diagram showing an embodiment of the present invention. When the gapless lightning arrester 2 is connected to the system bus 1, the voltage of the bus 1 is detected by the voltage detector 3 using PD or PT, and the number of lightning arrester operations is determined as the number of times the contact is turned on by the operation count meter 4 on the low voltage side of the lightning arrester 2. The current of the arrester 2 is detected by the current transformer 5. The measurement circuit 6 measures the leakage current IR based on the detected current I from the current transformer 5 and the detected voltage V from the voltage detector 3, or obtains the power loss W of the lightning arrester 2.

The monitoring device 7 determines the deterioration and lifespan of the lightning arrester 2 from the data on the number of ON times of the operation output contact of the operation counter 4, the leakage current IR or power loss W from the measurement circuit 6, and the detected voltage V. The monitoring operation of the monitoring device 7 is performed according to the monitoring flowchart shown in FIG.

In FIG. 2, the leakage current IR is taken in from the measuring circuit 6 (step St), and it is checked whether the output contact of the operation counter 4 was in the on state at the time of measuring this leakage current (step S2), and this output If the contact is in the OFF state, the presence or absence of voltage abnormality is checked from the system voltage V (step S3), and if it is normal, a deterioration determination program for the leakage current IR is activated to determine the presence or absence of deterioration (step S4). . This determination is made by comparing the leakage current (7) with a preset deterioration determination level, or by comparing the power loss W with its determination level. When it is determined in step S4 that there is no deterioration (step S5), the process returns to step St and the next leakage current or power loss data is acquired. When the judgment word in step S5 is deterioration, the deterioration judgment output is displayed and transmitted online to the monitoring room (step S6).

Therefore, deterioration determination from leakage current In or power loss is performed under the conditions that lightning arrester 2 is not acting as a lightning arrester and the grid voltage is normal, and reliable deterioration can also be determined with these conditions removed. can be obtained.

Next, when the contact of the operation counter is in the on state (step S2), it is determined that the leakage current (6) or power loss W at this time is due to surge absorption (step S7). Further, when the system voltage becomes abnormal (step S3), it is determined that the leakage current (8) or the power loss W at this time is due to the abnormality of the system voltage (S8). These determination results and the leakage current (8) or power loss at that time are used for the thermal stability determination of the lightning arrester (step S9) and the processing energy determination (SIO).

Thermal stability is determined by monitoring leakage current IR or power loss W for a certain period of time (approximately 1 minute to 12 hours) 17 and its rate of change over time d
Thermal stability is determined by the magnitude of rR/dt or dw/dt. For example, in the case of leakage current, if dll/dt>0, it will be determined that there is thermal runaway, and if dlR/dt=0, it will be determined that there is a risk of thermal runaway and caution is required, prompting continued monitoring, and dlR/dt=0. When dt<0, a three-step judgment is made to determine that the material is thermally stable. In such a thermal stability judgment, if it is determined that thermal stability exists or there is a risk of thermal stability (step 511), the process returns to step St, and in a thermal runaway state, the system is switched by displaying the thermal runaway judgment output and transmitting it online (step 5I2). We encourage the protection of such things.

Therefore, leakage current when a surge or abnormal voltage occurs■8
Alternatively, it is possible to check the thermal stability of the lightning arrester to determine whether thermal runaway occurs due to power loss W, and in addition to determining deterioration during normal conditions, it is possible to monitor whether the lightning arrester is normal or abnormal during surge absorption or due to system voltage abnormality.

Next, the processing energy is determined from the difference △IR or △W between the leakage current IR or power loss W at the time of surge absorption or abnormal voltage occurrence and the current IR or power loss W immediately after or immediately before, the processing energy of the lightning arrester EE= f, (△IR) E = f! (ΔW) is obtained, and this processing energy output (step 513) is used to determine the lifetime of the lightning arrester based on the magnitude of the processing energy of the lightning arrester and the magnitude of the integrated value.

Therefore, it is possible to determine the lifespan from the energy during surge absorption and abnormal voltage generation, which constitute most of the processing energy of the lightning arrester.

G1 Effects of the Invention As described above, according to the present invention, it is possible to determine the deterioration of a lightning arrester regarding leakage current or power loss, to determine thermal stability, and to process energy under the conditions of the operating state of the lightning arrester and the normal or abnormal state of the system bus voltage. Since the judgments are differentiated, it is possible to eliminate erroneous judgments in automatic monitoring of lightning arresters from leakage current or voltage loss, and to make appropriate judgments according to the environmental conditions of the lightning arrester, as well as accurate judgments including the degree of deterioration and life span. effective.

[Brief explanation of the drawing]

FIG. 1 is a device configuration diagram showing an embodiment of the present invention, FIG. 2 is a monitoring flowchart of the monitoring circuit in FIG. 1, and FIG. 3 is a heat balance characteristic diagram of a gapless arrester. 1...Bus bar, 2...Surge arrester, 3...Detector, 4...
・Operation counter, 5... AC generator, 6... Measuring circuit, 7
...Monitoring device. Fig. 1 Equipment configuration of the embodiment 2 people outside the diagram Fig. 2 Monitoring flowchart of the embodiment Fig. 3 Heat balance characteristic diagram of the earth arrester Temperature □

Claims (1)

[Claims] (1) An operation counter that obtains the number of lightning arrester operations using an output-on signal, a current transformer that detects the current of the arrester, a voltage detector that detects the voltage of the system bus to which the arrester is connected, and the current transformer. A measurement circuit that measures the leakage current or power loss of the lightning arrester from the detected current of the lightning arrester and the detected voltage of the voltage detector; means for determining deterioration of the lightning arrester with respect to the leakage current or power loss when the lightning arrester is in the state of detection, and means for determining the leakage current when the operation counter is in the detection state of lightning protection operation or the voltage detector is in the abnormality detection state of the system voltage. Alternatively, an automatic monitoring device for a gapless lightning arrester, comprising: a monitoring device having means for determining the thermal stability of the surge arrester from the time rate of change of power loss, and a means for determining processing energy.