JPH0499970A - Detecting apparatus for partial discharge pulse - Google Patents

Abstract

PURPOSE:To diagnose dielectric breakdown or the deterioration of fixing force during operation by detecting an electric signal by the detection coil wound around a troidal core and detecting the magnetic field generated by the current flowing to a power cable by an optical fiber magnetic field detector. CONSTITUTION:Only by allowing the power cable 1 of a rotary electric machine to pierce through a troidal core 2, a high frequency pulse signal being a partial discharge signal can be detected by the detection coil 3 wound around the core 2. Since an optical fiber magnetic field detector 5 is based on a Faraday element 9, the linear polarized wave passed through a polarizer 12 is rotated in its plane of polarization by the magnetic field generated by the current flowing to the cable 1 during the propagation through the element 9 and converted to the luminous intensity corresponding to an angle of rotation by a detector 10. This luminous intensity is converted to voltage by a photoelectric converter 7 to detect the magnetic field of the cable 1 and the current and current phase thereof are detected. Since the coil 3 and the detector 5 can detect a current on the coating of the cable 1, even when they are not connected to the terminal or wire of the electric rotary machine, partial discharge necessary for detecting the dielectric breakdown or fixing force deterioration of winding can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a device capable of detecting partial discharge pulses in electrical equipment while in a problem state.

(Conventional technology) 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 characteristics (insulation resistance, alternating current, dielectric Two methods are used: one is to measure the degree of deterioration of the winding insulation (loss angle, partial discharge, etc.), 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. Ta. 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 has become difficult to carry out deterioration judgments, and in cases where deterioration progresses rapidly, it may not be possible to take adequate measures.

In order to eliminate this drawback, a detection device (Utility Model Application No. 6O-158167) was put into practical use that measures partial discharge during the operation of a rotating electric machine, and the measured partial discharge pulse (discharge charge amount (q
)) occurs in which phase of the power supply voltage phase (ΦV) (hereinafter referred to as q-ΦV analysis), an insulator deterioration determination technology (Japanese Patent Application Laid-Open No. 58-153], No. 83, JP-A No. 83) 1986-203866) has also been put into practical use.

Such a method is said to be able to monitor the condition of the windings during operation, in addition to eliminating the above-mentioned drawbacks.

In particular, when the fixing force of the winding deteriorates due to vibrations generated during operation, the winding also vibrates independently, creating a gap between the slot and the winding and generating a partial discharge pulse (hereinafter referred to as slot discharge). By detecting this slot discharge, deterioration in the fixing force of the winding can be determined.

However, in the q-ΦV analysis performed by power supply voltage phase detection and partial discharge measurement, it was not possible to accurately determine the deterioration of the fixing force of the winding in a short time. This is because the vibration of the winding is determined by the electromagnetic force generated by the current flowing through the winding.

Electromagnetic force is proportional to the square of the current. Therefore, by detecting the power supply current phase and analyzing the relationship between the power supply current phase and the amount of partial discharge using the method described above, deterioration in the fixing force of the winding could be determined more accurately.

(Problems to be Solved by the Invention) As mentioned above, the drawback of the prior art is that the power supply voltage phase detection and partial discharge measurement detection cannot detect the slot discharge that occurs between the slot and the winding that vibrates due to the electromagnetic force determined by the current. Due to accurate identification, it was not possible to determine whether the fixing force of the winding had deteriorated.

Therefore, it is an object of the present invention to solve the above problems and provide a partial discharge pulse detection device that can easily detect partial discharge pulses and power supply current phases necessary for determining the deterioration of the fixing force of a stator winding of a rotating electric machine.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the partial discharge pulse detection device of the present invention includes a toroidal core with high magnetic permeability through which a power cable passes, and a current detector wound around the toroidal core. an optical fiber magnetic field detector disposed near the power cable and connected to the opto-electrical converter; and a fiber optic magnetic field detector connected to the current detector via a partial discharge electric signal input circuit, and the The structure includes a partial discharge measuring device connected to an optical-to-electrical converter.

(Function) According to the partial discharge pulse detection device of the present invention, the electric signal of partial discharge can be detected by the detection coil from above the conductor coating without connecting the partial discharge pulse detection device to a conductor such as a terminal of an electric device. , the phase of the power supply current can be detected by using an optical fiber magnetic field detector to detect the magnetic field generated by the current flowing through the power cable.

(Example) The present invention will be described below based on an example shown in FIGS. 1 and 2. The partial discharge pulse detection device of this embodiment includes a toroidal core 2 of high magnetic permeability through which a power cable 1 of a rotating electric machine passes, a detection coil 3 wound around the toroidal core 2, and a detection coil 3 connected to the detection coil 3. It consists of a current detector 4 and an optical fiber magnetic field detector 5. The detection coil 3 is connected to a partial discharge electric signal input circuit 6, and the optical fiber magnetic field detector 5 is connected to a partial discharge measuring device 8 via an optical-electrical converter 7.

The toroidal core 2 is manufactured by TDK Corporation and has a magnetic permeability of 2100 (H/m), which remains constant up to the high frequency range.
The optical fiber magnetic field detector 5 is composed of a Faraday element 9, an analyzer 10, a mirror II, and a polarizer 12, as shown in FIG.

With this configuration, a high frequency pulse signal, which is a partial discharge signal, can be detected simply by passing the power cable 1 of the rotating electric machine through the toroidal core 2.

Furthermore, since the optical fiber magnetic field detector 5 mainly includes a Faraday element 9, the linearly polarized light wave that has passed through the polarizer 12 is polarized due to the magnetic field generated by the current flowing through the power cable 1 while propagating within the Faraday element 9. rotates, and the analyzer lO converts it into light intensity according to the rotation angle. light-
The electrical converter 7 electrically processes the light intensity and converts it into a voltage so that the magnetic field of the power cable 1 can be detected, and the current and current phase of the power cable 1 can be detected.

Both the detection coil 3 and the optical fiber magnetic field detector 5 can detect current from above the sheath of the power cable 1, so the detection coil 3 and the optical fiber magnetic field detector 5 can detect the windings of the rotating electrical machine without having to connect the detector to a conductor such as a terminal or line of the rotating electrical machine. It is possible to accurately detect partial discharge information necessary for detecting deterioration of insulation and fixing force.

Further, the toroidal core 2 is not limited to a circular shape, and even if it is oval or square, the same operation can be obtained. Furthermore, the toroidal core 2 is made into a U-shape, for example, by cutting a circle into 1/2, and the cut surfaces are aligned with each other. Such a two-part toroidal core allows the power cable 1 to be easily passed through the toroidal core 2 without temporarily stopping the rotating electric machine.

〔Effect of the invention〕

As explained above, according to the present invention, the current phase of the line of the target machine can be detected without being connected to the line, the detection device can be installed without stopping the rotating electric machine, and the winding vibration during normal operation can be detected. Since the slot discharge caused by such factors can be measured with high accuracy, it is possible to easily diagnose insulation deterioration and fixing force deterioration of electrical equipment during operation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a partial discharge pulse detection device according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an optical fiber magnetic field detector according to the present invention. 1... Power cable 2... Toroidal core 3...
...Detection coil 4...Current detector 5...Optical fiber magnetic field detector 6...Partial discharge electrical signal input circuit 7...Optical-electrical converter 8...Partial discharge measuring device 9
...Faraday element 10...Analyzer 11...
Mirror 12...Polarizer agent Patent attorney
Noriyuki Noriyuki (I)

Claims (1)

[Claims] A toroidal core with high magnetic permeability through which a power cable passes, a detection coil wound around the toroidal core and connected to a current detector, and an optical fiber arranged near the power cable and connected to an optical-to-electrical converter. a magnetic field detector;
A partial discharge pulse detection device comprising: a partial discharge measuring device connected to the current detector via a partial discharge electrical signal input circuit and connected to the optical-to-electrical converter.