JPH04324377A - Partial discharge pulse detector - Google Patents

Abstract

PURPOSE:To enable the detection of insulation state without stopping a rotary electric machine by detecting a partial discharge pulse and a voltage phase of a line of a machine as object with no connection to the line. CONSTITUTION:A toroidal coil 2 uses a ferrite core PE-1 with a magnetic permeability high and fixed to a high frequency area. Hence, a current detector 4 detects a high frequency pulse signal of a partial discharge signal only passing through a power cable 1 of a rotary electric machine. A optical fiber electric field detector 5 which is based on a Pockels element 9 converts light intensity into a voltage with a photoelectric converter 7 as a refractive index of the element 9 varies with a potential difference of surfaces 13 and 14, which allows the detector 5 to detect a power source voltage phase of the cable 1. Thus, as detectors 4 and 5 detect current and voltage from on the cover of the cable 1, information on insulation degrading and a partial discharge of a coil of the rotary electric machine can be detected accurately without connection of the detectors to a line or the like of the rotary electric machine.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge pulse detection device for monitoring abnormalities in electrical equipment while energized.

0002

[Prior Art] Conventionally, in order to determine abnormalities in a rotating electric machine, especially deterioration of the stator windings, after stopping the rotating electric machine, high voltage is applied to the windings and various electrical properties (insulation resistance, alternating current, dielectric Two methods have been used: one is to measure the degree of deterioration of the winding insulation (loss angle, partial discharge), and the other is a mechanical method to determine mechanical damage to the insulation due to hammering noise and deterioration of the winding fixing force. . In order to determine these deterioration conditions, it is necessary to stop the rotating electric machine, disconnect the line, and in some cases remove the rotor. Therefore, determining insulation deterioration requires a great deal of time, effort, and cost, and requires frequent work. It became difficult to carry out deterioration judgments, and in cases where deterioration progressed rapidly, sufficient measures could not be taken. In order to eliminate this drawback, we developed a detection device that measures partial discharges during the operation of rotating electric machines.
0-158167) was put into practical use, and a technology for determining deterioration of insulators (Japanese Unexamined Patent Publication No. 58-15318
3, JP-A-60-203866) has also been put into practical use. However, in order to detect the power supply voltage phase required for analysis, this method requires stopping the rotating electrical machine and disconnecting the system for safety, then removing the terminal insulation of the rotating electrical machine and detecting the power voltage phase on the conductor. The equipment had to be connected, and the connection of the rotating electric machine had to be changed in order to determine the deterioration of the windings. Conventional power supply voltage phase detection devices usually use a potential transformer (hereinafter referred to as PT) because the power source of the rotating electrical machine is high voltage.
The voltage is lowered by the voltage and connected to the partial discharge measurement system. There is a way to permanently install a PT so that you do not have to change the connection of the rotating electric machine every time you measure partial discharge, but in this case,
Protective devices for the T were required in case of an abnormality, and maintenance and inspection of those protective devices including the PT was also required.

0003

[Problems to be Solved by the Invention] The disadvantages of the above-mentioned prior art are that the work to connect a detector for detecting the power supply voltage phase must be performed after stopping the operation of the rotating electric machine and disconnecting the system; The permanent installation of PT, which is a detector, is
There was a need for protective equipment in case of abnormalities in the PT, and maintenance and inspection of these equipment was also necessary.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a partial discharge pulse detection device capable of solving the above-mentioned problems and easily detecting partial discharge pulses and power supply voltage phases necessary for determining deterioration of a stator winding of a rotating electric machine. [Structure of the invention]

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a partial discharge system comprising a high permeability toroidal core through which a power cable passes and a detection coil is wound, and an optical fiber electric field detector as a pair. It is a pulse detection device.

[0006]

[Operation] The above partial discharge pulse detection device is permanently installed on the terminal conductor coating of the rotating electrical machine, and the detection coil detects the partial discharge pulse while the rotating electrical machine is operating, and the optical fiber electric field detector detects the voltage phase of the terminal conductor. To detect.

[0007]

Embodiment The present invention will be explained below based on an embodiment shown in FIGS. 1 and 2. The partial discharge pulse detection device of the present invention comprises a high permeability toroidal coil 2 through which a power cable 1 of a rotating electric machine passes, a detection coil 3 wound around the toroidal coil 2, and an optical fiber electric field detector 5. The detection coil 3 includes a current detector 4 and a partial discharge electric signal input circuit 6, and the optical fiber electric field detector 5 includes a photo-electrical converter 7.
are connected to the partial discharge measuring device 8 through the respective terminals.

The toroidal coil 2 uses a ferrite core PE-1 manufactured by TDK Corporation, and the optical fiber electric field detector 5
FOES manufactured by Furukawa Electric Co., Ltd. is used. The optical fiber electric field detector 5 is composed of a Pockels element 9, an analyzer 10, a quarter-wave plate 11, and a polarizer 12, as shown in FIG. 2, and the plane 13 of the Pockels element 9 is installed perpendicular to the direction of the electric field.

The current detector 4 uses a ferrite core PE-1, which has a high magnetic permeability of 2100 [H/m] and whose magnetic permeability is constant up to a high frequency range, for the toroidal coil 4. A high-frequency pulse signal, which is a partial discharge signal, can be detected simply by passing the power cable 1 of the rotating electrical machine. Furthermore, since the optical fiber electric field detector 5 is mainly composed of a Pockels element 9, the refractive index of the element changes due to the potential difference between the surfaces 13 and 14, so the optical-electrical converter 7 electrically processes the light intensity. Since it is converted into a voltage, the power supply voltage phase of the power cable 1 can be detected.

[0010] Both the current detector 4 and the optical fiber electric field detector 5 can detect current and voltage from above the coating of the power cable 1, so there is no need to connect the detector to a conductor such as a terminal of a rotating electric machine or a line. It is possible to accurately detect partial discharge information necessary for detecting insulation deterioration and fixing force deterioration in rotating electrical machine windings.

[0011] The toroidal coil 2 is not limited to a circular shape, and even if it is oval or square, the same operation can be obtained. For the series, a toroidal coil 2 is used, for example, in a U-shape obtained by cutting a circle into 1/2, with the cut surfaces aligned with each other. Such a two-part toroidal coil allows the power cable 1 to be easily passed through the toroidal coil 2 without temporarily stopping the rotating electric machine. Note that the optical fiber electric field detector 5 can detect the power supply voltage phase even if it is installed near the power cable 1 and away from the toroidal coil 2.

0012

[Effects of the Invention] As explained above, since the partial discharge pulse detection device is capable of detecting the voltage phase of the line of the target machine without being connected to the line, the detection device can be installed without stopping the rotating electric machine. Since partial discharge can be measured with high accuracy, it is possible to easily diagnose insulation deterioration and fixing force deterioration of rotating electric machine windings during operation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an optical fiber electric field detector used in the present invention.

[Explanation of symbols]

Claims (1)

[Claims] 1. A partial discharge pulse detection device comprising a pair of a high permeability toroidal core through which a power cable passes and a detection coil is wound, and an optical fiber electric field detector.