JPS59230442A - Stator winding for high voltage rotary electric machine - Google Patents

Abstract

PURPOSE:To enable to monitor the insulation of a winding for a rotary electric machine during operation without using a coupling capacitor by electrically insulating a low resistance corona shielding layer of a partial coil from a core, and grounding via a resistor. CONSTITUTION:A partial coil 6 of a winding of a rotary electric machine is contained in a slot through an insulating liner 11 between a low resistance corona shielding layer 8 and a core 5, a resistor 14 is connected via connecting pieces 12a, 12b and lead wirings 13 to the layer 8, and one end of the resistor 14 is grounded. Thus, a partial discharge detector which is formed of the capacitance C1 of the partial coil of the winding, the grounding resistor R of the shelding layer and the capacitance C2 of the other coil is formed, thereby enabling to detect and measure the partial discharge created at the winding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a stator winding of a high-voltage rotating electric machine that is provided with measures to easily detect partial discharge.

[Prior art and its problems]

In order to prevent accidents caused by insulation deterioration of rotating electric machine windings, it is desirable to conduct periodic insulation diagnostic tests or to monitor insulation deterioration during operation, and to take appropriate measures based on the results. .

Aesthetic insulation deterioration phenomena in high-voltage rotating electric machine windings include the occurrence and increase of peeling and cracking of the insulation layer due to thermal or mechanical stress. therefore,
To detect the phenomenon of insulation deterioration in the windings of high-voltage rotating electric machines, tests aimed at detecting the state of voids in the insulation layer, ie, partial discharge tests, etc. are applied.

Partial discharge tests on windings of high-voltage rotating electric machines or partial discharge monitoring during operation are usually carried out as shown in Figure 1, as shown in Figure 1.
3 to 3C are connected respectively, and the partial discharge measuring device 4 is used. However, this method naturally has the disadvantage of requiring a coupling capacitor and its installation location.

[Purpose of the invention]

The present invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a stator winding for a high-voltage rotating electric machine in which partial discharge can be detected without using a coupling capacitor.

[Key points of the invention]

This invention provides a stator winding for a high-voltage rotating electrical machine consisting of a coil provided with a low-resistance corona shield, in which the low-resistance corona shield layer of the negative portion of the coil is electrically insulated from the iron core,
By forming a partial discharge detection circuit consisting of the capacitance of the insulating layer of this coil, the capacitance of the insulating layer of the other coils, and the resistor, which is grounded through a resistor, it is possible to detect the partial discharge during operation without using a coupling capacitor. It provides high voltage rotation horizontal stator windings with insulation monitoring.

[Embodiments of the invention]

Normally, in a rotating electric machine winding with a rated voltage of 6 Kv or more, all the coils 6 that make up the winding are connected to an iron core 5 as shown in FIG.
A low-resistance corona shield R8 for preventing slot corona is applied to the surface of the insulating layer 7 at the portion that enters the slot, and a conductive liner 9 is provided for electrically connecting this low-resistance corona shield layer 8 to the iron core 5. is housed in the slot, interposed between it and the iron core. IO is a high resistance corona shield.

This invention replaces the conductive liner 9 with a high-resistance liner or high-resistance liner 11 for some of the coils of the winding of the high-voltage rotating electric machine as described above, and connects the low-resistance corona shield layer 8 with a resistor 14. By grounding the coil, the capacitance of the insulating layer of the coil serves as the coupling capacitance of the partial discharge detection circuit, and the grounding resistor 14 of the low resistance corona shield also serves as the detection resistance of the detection circuit.

FIG. 3 shows an embodiment of the present invention, in which a part of the coil 6 of the winding of a rotating electric machine is housed in a slot with an insulating liner 11 interposed between a low resistance corona shield layer 8 and an iron core 5. , connection pieces 12a, 1 are attached to the low resistance corona shield layer 8.
2b and a resistor 14 via the lead wire 13,
One end of the resistor 14 is grounded. Needless to say, the system is grounded through the resistor not only during insulation diagnosis but also during operation. Here, for the insulating liner 11, a general insulating material in the form of woven fabric, non-woven fabric, or film is used. Further, a high resistance liner having a resistance value that does not affect the ground resistance value of the low resistance corona shield layer 8 due to the resistor 14 may be used.

The resistor 14 serves both as a detecting element (partial discharge detecting element) of the partial discharge measuring circuit and as a grounding resistor for the low resistance corona shield N8, and is approximately 1Ω. As the detection element, a reactor or a capacitor can be used in addition to a resistor. connection piece 12a,
12b uses a metal plate and has a low resistance corona shield layer 8 (!
: [Fixed to one or several locations of the low-resistance corona shield layer 8 with a string or tape so as to be electrically connected.

By applying the above treatment to some of the coils in the winding, the capacitance C1 of that coil, the grounding resistance R of the low-resistance corona shield layer of that coil, and the capacitance of other coils can be reduced as shown in FIG. A partial discharge detection circuit consisting of C2 is formed, and the partial discharge measuring device 4
By connecting to the 2nd winding, it becomes possible to detect and measure the partial discharge that occurs in the 2nd winding.

According to this invention, for some of the coils 6 of the rotating electric machine winding, the low resistance corona shield layer 8 is electrically insulated from the iron core 5 and grounded via the resistor 14. capacitance.

A partial discharge detection circuit is formed consisting of the capacitance of the insulating layer of the other coils and the resistor described above, and if the above treatment is applied to a coil that is at a low potential that does not cause partial discharge during operation, the capacitance of that coil will change. acts as the capacitance of the coupling capacitor mentioned in the prior art section, and can detect partial discharges occurring in other coils.

Also, if you want to measure a specific coil, apply the above treatment to the coil you want to measure.
Partial discharges occurring in that coil can be detected with higher sensitivity than partial discharges occurring in other coils. That is, the measuring device input voltages v1 and v2 for the partial discharge generated in the coil subjected to the above treatment and the partial discharge generated in other coils are as follows: Partial discharge charge amount C7; Capacitance of the coil subjected to the above treatment C2; capacitance e of all other coils; base of natural logarithm. Therefore, the ratio of detection sensitivities between the two, V 1 /V 2, is vl
/V 2 =C2/C1 Also, by making the relationship C1(C2 hold true between C1 and C2, Vl>>V2, so when you want to measure a specific coil,
By applying the above-mentioned treatment to the coil, it is possible to measure the partial discharge generated in the coil with high sensitivity.

〔Effect of the invention〕

This invention electrically insulates the low-resistance corona shield layer of some coils from the iron core and grounds them via a resistor, thereby reducing the capacitance of the insulating layer of this coil and the capacitance of the insulating layer of other coils. and the resistor to form a partial discharge detection circuit,
This provides the effect of making it possible to monitor the insulation of the rotating electric machine winding during operation without using a coupling capacitor.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional partial discharge detection method, FIG. 2 is a partial cross-sectional view of a stator of a rotating electrical machine with a rated voltage of 6 KV or more, and FIG. 3 is a schematic diagram of a stator of a rotating electrical machine according to an embodiment of the present invention. FIG. 4, a partial cross-sectional view, is a simulated circuit diagram relating to partial discharge detection of a rotating electric machine winding according to an embodiment of the present invention. 4... Partial discharge measuring device, 6... Coil conductor, 7...
Coil insulation, 8...Low resistance corona shield, 11...
・Insulation liner, 12a, 12b...Connection piece, 14・
··Resistor.

Claims (1)

[Claims] 1) In the stator winding of a high-voltage rotating electrical machine consisting of coils provided with a low-resistance corona shield, the low-resistance corona shield layer of some of the coils is electrically insulated from the iron core and grounded via a partial discharge detection element. A stator winding for a high-voltage rotating electrical machine characterized by: