CN-115856442-B - Casing dielectric loss measurement method

CN115856442BCN 115856442 BCN115856442 BCN 115856442BCN-115856442-B

Abstract

The invention discloses a sleeve dielectric loss measurement method. The sleeve comprises a conducting rod, a capacitor core and an insulating shell which are sequentially arranged, the capacitor core comprises capacitor screens which are arranged along the radial direction, the sleeve dielectric loss measuring method comprises the steps of conducting low insulation treatment on the outer surface of the insulating shell, constructing a dielectric loss measuring balance bridge, connecting a power line of the dielectric loss measuring balance bridge to the conducting rod, inputting a preset voltage source to the power line, connecting a test line of the dielectric loss measuring balance bridge to a terminal capacitor screen, and determining a sleeve dielectric loss value according to dielectric loss measuring balance bridge parameters when the dielectric loss measuring balance bridge is balanced, wherein the dielectric loss measuring balance bridge parameters comprise dielectric loss measuring balance bridge resistance parameters and dielectric loss measuring balance bridge capacitance parameters. The scheme eliminates the influence of humidity and insulation outside the sleeve on dielectric loss measurement, and improves the accuracy of the sleeve dielectric loss measurement.

Inventors

ZHOU JIETAO
LI XUHONG
ZHANG GUILIN
LI TAO
YANG XIEWEI
XING XIBO
FANG WENTIAN
ZHU YUZHAO
FANG YIYUE

Assignees

广东电网有限责任公司
广东电网有限责任公司揭阳供电局

Dates

Publication Date: 20260505
Application Date: 20221123

Claims (6)

1. The sleeve comprises a conductive rod, a capacitor core and an insulating shell which are sequentially arranged; the insulating shell comprises a plurality of porcelain skirts, the capacitor core comprises capacitor screens which are arranged along the radial direction, and the method is characterized by comprising the following steps of: the low insulation treatment on the outer surface of the insulating shell comprises the steps of connecting a resistor in parallel between each two petunts, connecting a reactance in parallel between each two petunts, or connecting impedance in parallel between each two petunts; constructing a dielectric loss measurement balance bridge; The power line of the dielectric loss measurement balance bridge is connected to the conducting rod, and the power line is input with a preset voltage source; And when the dielectric loss measurement balance bridge is balanced, determining a sleeve dielectric loss value according to dielectric loss measurement balance bridge parameters, wherein the dielectric loss measurement balance bridge parameters comprise dielectric loss measurement balance bridge resistance parameters and dielectric loss measurement balance bridge capacitance parameters.
2. The casing dielectric loss measurement method according to claim 1, wherein the low insulation treatment on the outer surface of the insulating casing comprises: and coating a low-insulation substance on the outer surface of the insulating shell.
3. The method for measuring the casing dielectric loss according to claim 1, wherein a resistor is connected in parallel between each two porcelain skirts, specifically: the head end is the conducting rod end, the tail end is the insulating shell bottom ground flange, and the parallel resistor is connected between two porcelain skirts respectively.
4. The method for measuring casing dielectric loss according to claim 1, wherein the balance bridge for dielectric loss comprises a first variable resistor, a second resistor, a first variable capacitor and a second capacitor; the conductive rod of the sleeve is electrically connected with a power line of the dielectric loss measurement balance bridge and is electrically connected with a first end of the second capacitor; the end capacitor screen of the sleeve is electrically connected with the first end of the first variable resistor, the second end of the first variable resistor is electrically connected with the first end of the second resistor and the first end of the first variable capacitor and grounded, the second resistor and the first variable resistor are electrically connected in parallel, and the second end of the second resistor and the second end of the first variable capacitor are electrically connected with the second end of the second capacitor.
5. The method of claim 4, wherein the balance bridge further comprises a current meter; The first end of the ammeter is electrically connected with the first end of the first variable resistor, and the second end of the ammeter is electrically connected with the second end of the first variable capacitor and the second resistor.
6. The method of claim 5, wherein determining a casing dielectric loss value based on a dielectric loss measurement balance bridge parameter when the dielectric loss measurement balance bridge is balanced comprises: and when the current count is zero, determining a sleeve dielectric loss value according to the first variable resistor, the second resistor, the first variable capacitor and the second capacitor.

Description

Casing dielectric loss measurement method Technical Field The embodiment of the invention relates to a transformer technology, in particular to a sleeve dielectric loss measurement method. Background The capacitive high-voltage bushing is an external connection component which is indispensable to the power transformer as a typical oilpaper insulation device. The data show that the accidents of the transformer bushing of 110kV and above account for a certain proportion in the total number of accidents, and the proportion of accidents caused by the bushing is increased along with the increase of voltage level. The bushing test is an important part in the conventional test of the transformer, and the bushing is exposed to moisture, ageing and the like to cause the bushing to explode, thereby causing serious consequences. The capacitance and dielectric loss of the sleeve are key indexes reflecting the running quality of the sleeve, but the dielectric loss test is easily affected by the environment during the field test, so that the dielectric loss test value is distorted, and the judgment is affected. Among the many influencing factors, the environmental humidity is the most difficult to solve, and directly influences the insulation condition of the surface of the sleeve so as to influence the dielectric loss test value, and the influence of the environmental humidity on the dielectric loss test value of the sleeve is not unilateral increase or decrease, but is possible in both aspects, namely the dielectric loss test value is increased or decreased, so that misjudgment or missed judgment in the field test is likely to be caused. Disclosure of Invention The invention provides a sleeve dielectric loss measurement method, which is used for eliminating the influence of humidity and sleeve external insulation on dielectric loss measurement and improving the accuracy of a sleeve dielectric loss test. The embodiment of the invention provides a sleeve dielectric loss measurement method, which comprises a conducting rod, a capacitor core and an insulating shell which are sequentially arranged; the capacitive core comprises capacitive screens which are arranged along the radial direction, and is characterized in that the sleeve dielectric loss measuring method comprises the following steps: Low insulation treatment is carried out on the outer surface of the insulating shell; constructing a dielectric loss measurement balance bridge; The power line of the dielectric loss measurement balance bridge is connected to the conducting rod, and the power line is input with a preset voltage source; And when the dielectric loss measurement balance bridge is balanced, determining a sleeve dielectric loss value according to dielectric loss measurement balance bridge parameters, wherein the dielectric loss measurement balance bridge parameters comprise dielectric loss measurement balance bridge resistance parameters and dielectric loss measurement balance bridge capacitance parameters. Optionally, the insulating housing includes a plurality of skirts; A low insulation treatment on the outer surface of the insulating housing, comprising: and resistors are connected in parallel between the two porcelain skirts. Optionally, the low insulation treatment on the outer surface of the insulation shell comprises: and coating a low-insulation substance on the outer surface of the insulating shell. Optionally, the insulating housing includes a plurality of skirts; A low insulation treatment on the outer surface of the insulating housing, comprising: And a shunt reactor is arranged between the two porcelain skirts. Optionally, the insulating housing includes a plurality of skirts; A low insulation treatment on the outer surface of the insulating housing, comprising: and impedance is connected in parallel between the two porcelain skirts. Optionally, a resistor is connected in parallel between each two porcelain skirts, specifically: the head end is the conducting rod end, the tail end is the insulating shell bottom ground flange, and the parallel resistor is connected between two porcelain skirts respectively. Optionally, the dielectric loss measurement balance bridge comprises a first variable resistor, a second resistor, a first variable capacitor and a second capacitor; the conductive rod of the sleeve is electrically connected with a power line of the dielectric loss measurement balance bridge and is electrically connected with a first end of the second capacitor; The end capacitor screen of the sleeve is electrically connected with the first end of the first variable resistor, the second end of the first variable resistor is electrically connected with the first end of the second resistor and the first end of the first variable capacitor and grounded, the second resistor and the first variable resistor are electrically connected in parallel, and the second end of the second resistor and the second end of the first variable capacitor are ele