KR950033506A

KR950033506A - Method and device for diagnosing live cable insulation degradation by measuring AC voltage

Info

Publication number: KR950033506A
Application number: KR1019950009286A
Authority: KR
Inventors: 다다하루 나까야마
Original assignee: 구라우찌 노리요시; 스미또모 덴끼 고교 가부시끼가이샤
Priority date: 1994-04-22
Filing date: 1995-04-20
Publication date: 1995-12-26
Also published as: JPH07294573A; KR100241314B1

Abstract

(목적) 고전압 케이블의 절연열화 정도를 활선 운전중에 측정용 전원을 사용하지 않고 진단하는 방법을 제공한다.(Objective) Provides a method of diagnosing the degree of insulation degradation of high-voltage cables without using a power supply for measurement during live operation.

(구성) 대상케이블(2)의 차폐단과 대지간에 전환수단(12)에 의하여 선택되는 값이 다른 제1 및 제2콘덴서(13,14) 및 값이 다른 제2저항(15,16)으로 이루어지는 4종의 선택측정 접지 임피던스를 삽입하고, 다시 통상 항상 이들의 1개와 병렬로 삽입되는 제3의 콘덴서(17)의 존재하에서 직류전류의 침입을 배제한 교류전압계 (19)에 의하여 각 선택측정 접지 임피던스의 1개를 선택했을 때에, 그 접지 임피던스의 양단에 발생하는 실효전압치를 교류 전압계로 측정한다. 이 결과 얻어진 4개의 실측 전압치로부터 측정대상 케이블의 절연체가 가지는 등가중심 잡음주파수에 있어서의 기전류기능을 산출하고, 이 기전류기능의 대소로부터 케이블의 절연열화 정도를 판단한다.(Configuration) The first and second capacitors 13 and 14 having different values selected by the switching means 12 between the shielding end and the ground of the target cable 2 and the second resistors 15 and 16 having different values. Each selective measurement ground impedance is inserted by an alternating voltage voltmeter 19 which inserts four selective measurement ground impedances and, in the presence of a third condenser 17, which is usually always inserted in parallel with one of them, eliminates the intrusion of direct current. When one is selected, the effective voltage value generated at both ends of the ground impedance is measured with an AC voltmeter. As a result, an electromotive current function at the equivalent center noise frequency of the insulator of the measurement target cable is calculated from the four measured voltage values obtained, and the degree of insulation degradation of the cable is determined from the magnitude of the electromotive current function.

Description

Method and device for diagnosing live cable insulation degradation by measuring AC voltage

본 내용은 요부공개 건이므로 전문내용을 수록하지 않았음Since this is an open matter, no full text was included.

제1도는 본 발명의 일 실시예를 나타낸 회로 구성도, 제2도는 제1도에 나타낸 본 발명의 실시예의 등가회로도.1 is a circuit diagram showing one embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of an embodiment of the present invention shown in FIG.

Claims

Four selective measurement ground impedances consisting of a first measuring capacitor having a different value and a second measuring capacitor having a different value and a first measuring resistor having a different value, and a third capacitor with a shielding end of the live power cable. The four selective measurement ground impedances in parallel between the grounds and in the state in which the third capacitor is connected between the shield terminal of the live power cable and the ground at least when selecting the first and second measurement resistances. Is selected between the shield and the ground, and the AC effective voltage generated at both ends of the selective measurement ground impedance is measured by a high-voltage voltmeter indicating a true effective voltage excluding the intrusion of DC current. Performing four selective measurement ground impedances respectively and measuring the four alternating current effective voltage values; Calculates the first electromotive current function at the fundamental frequency of the live cable insulator and the second electromotive current function at the equivalent center noise frequency of N times the fundamental frequency, A live cable insulation degradation diagnosis method according to an AC voltage measurement, comprising the step of determining the degree of insulation degradation of the cable from the large and small.

When selecting at least the first and the second measurement resistance, in the state where the third capacitor is connected between the shield end of the live power cable and the earth, one of the four selective measurement ground impedances is selected and connected between the shield and the earth. Selective measurement Measured by an AC voltmeter indicating the effective voltage of the needle excluding the intrusion of AC current generated at both ends of the ground impedance, the measurement is performed for each of the four selected measurement ground impedances, and the four AC effective voltage values are measured. Calculates the first electromotive current function at the fundamental frequency of the live cable insulator and the second electromotive current function at the equivalent center noise frequency of N times the fundamental frequency from the measured four AC alternating current effective voltage values. Used for diagnosing live cable insulation degradation, which determines the degree of insulation degradation of the cable from the magnitude of the second electromotive current function. In the insulation deterioration diagnostic apparatus, the third capacitor connected between the shielding end of the live power cable and the ground, the first measurement capacitor and the second measurement capacitor having different values, and the first measurement having different values. The selected selective measurement ground impedance consisting of a resistor and a second measured resistance, and one of the four selective measurement ground impedances is selected and connected between the shield of the active cable and the ground, and the selected selective measurement ground And a means for connecting both ends of the impedance to the AC voltmeter connected in series to a capacitor for DC current blocking.

※ Note: The disclosure is based on the initial application.