JPH0474974A - Method for diagnosing insulation of high voltage apparatus - Google Patents

Abstract

PURPOSE:To precisely grasp a state of insulation deterioration by analyzing insulation characteristics on the basis of this summary value, adding up the charge amount of detected discharge pulses every cycle part of the voltage applied to a sample in an insulation diagnosis by partial discharge pulses. CONSTITUTION:A transformer 2 applies an AC voltage to a sample 1. A partial discharge pulses detected at a detecting element 3 is measured by a tuning type partial discharge measuring apparatus 4. A sampling period of the partial discharge pulse is made 5mus. The measured discharge pulses are stored to a memory 6. Charge amounts q of discharge pulses of positive and negative polarities are added by a computer 7 every AC one cycle respectively and the added values SIGMAq(+) and SIGMAq(-) are found. Changes of the sum totals SIGMAq(+) and SIGMA(-) to the charge time are pursued and the progress conditions of an insulation deterioration and the indication just short of a dielectric breakdown are grasped, for instance in the 16kV charge test of a stator coil for a high voltage rotating machine.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an insulation diagnosis method for high voltage equipment that measures and analyzes partial discharge occurring in electrical equipment and evaluates the insulation state of the equipment, and particularly relates to This invention relates to a diagnostic method that accurately expresses the state of deterioration.

B1 Summary of the Invention The present invention provides a first method for storing the waveform of the voltage applied to a sample in an insulation diagnosis method for high voltage equipment that measures and analyzes partial discharges occurring in electrical equipment and evaluates the insulation state of the equipment.
A second waveform storage device stores the waveform of the detected partial discharge pulse, and a computer analyzes the data. The present invention provides a technology that accurately represents the state of insulation deterioration by summing up the amount of charge and analyzing the insulation characteristics using the summed value.

C1 Conventional technology The partial discharge measurement method for testing the insulation properties of high voltage equipment is as follows:
According to the ``High Voltage Testing Handbook'' edited by the Institute of Electrical Engineers of Japan, the methods shown in the table below are adopted.

Table 1: However, fo is the tuning center frequency, fl is the lower limit frequency, f2
is the upper limit frequency and Δf is the bandwidth.

Items that can be ascertained through these measurements include partial discharge charge, frequency of occurrence, starting voltage, etc., and conventionally, the partial discharge resistance of an insulator has been evaluated based on these.

D3 Problems to be Solved by the Invention However, in the conventional partial discharge measurement method described above, the various items to be measured and the condition of the insulator, such as the size and amount of voids that are defects, the degree of electric field concentration, and the state of deterioration of the insulation, cannot be measured. etc., and it cannot be said that these measurement items clearly express the condition of the insulator, so they can only be estimated warmly.

The present invention was created in view of these problems, and
The objective is to provide an insulation diagnosis method for high voltage equipment that accurately expresses the state of insulation deterioration.

E3 Means for solving the problem The means for solving the above problem in the present invention is an insulation diagnosis of high-voltage equipment that detects, measures, and analyzes the waveform of a partial discharge pulse with a partial discharge measuring device installed in a sample. The method includes a first waveform storage device that stores the waveform of the voltage applied to the sample, a second waveform storage device that stores the waveform of the detected partial discharge pulse, and a computer that analyzes the data, This method is based on an insulation diagnosis method for high-voltage equipment in which the amount of charge of the detected discharge pulses is summed up for each cycle of the voltage applied to the sample, and the insulation characteristics are analyzed based on the summed value.

F9 action The present invention measures pulses generated by partial discharge with a partial discharge measuring device, stores the measured discharge pulses in a storage device, and calculates the charge amount q of the discharge pulses per Act cycle minute by computer. The total value Σq is used to evaluate the condition of the insulator. In order to make the discharge pulse correspond to the ACI cycle, the waveform of the AC voltage applied to the sample is also stored in another storage device.

Although the maximum discharge charge amount, which is instantaneous data of partial discharge, does not change much over time, the total value Σq gradually changes over time.

Therefore, if the changes are tracked intermittently, the degree of insulation deterioration can be accurately grasped.

G. Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of the present invention.

In the figure, 1 is a sample, 2 is a transformer that applies an AC voltage to the sample 1, 3 is a partial discharge detector installed in the sample 1, and 4 is a known tuning device that measures the detected partial discharge pulse. 5 is a first storage device for phase detection that stores the waveform of the AC voltage, 6 is a second storage device for charge amount detection that stores the waveform of the partial discharge pulse, and 7 is each data. It is a computer that stores, calculates, and analyzes information. The computer 7 has a keyboard 71 . CRT display 72
, printer 73. X-Y plotter 74. A floppy disk 75 or the like is connected. This device measures pulses generated by partial discharge with a partial discharge measuring device 4, stores the measured discharge pulses in a second storage device 6, and calculates the charge amount q of the discharge pulses with a computer 7. ACI
The values are summed per cycle, and the state of the insulator is evaluated using the summed value Σq. The AC voltage waveform for ACI cycles is stored in the first storage device 5.

Here, the sampling period of the partial discharge pulse was set to 5 μs, the capacitance of the first and second storage devices was set to 4 words, and the following items were measured.

■Maximum discharge charge of positive discharge pulse; Qmax (10)■
Maximum discharge charge of negative polarity discharge pulse; Qmax(-)■A
Total discharge charge per CI cycle; Σq(+)■ACI
Total discharge charge per cycle; Σq(-) Sample 1 is a stator coil for a high-voltage rotating machine, and the voltage is 16 kV.
A power application test was conducted, and the partial discharge characteristics during power application were measured and analyzed. FIG. 2 is a waveform diagram showing an example of the results. Note that the measurement voltage was 16 kV, which is the same as the applied voltage. As shown in FIG. 2, partial discharge measurements were carried out intermittently during the voltage application test, and the maximum discharge charges of positive and negative polarities and the total discharge charge per AC cycle Qmax (+) were measured.

Qmax(-), Σq(+), Σq(-)
seek.

In the same figure, the peak value of the applied voltage Vp-p20v is set to 1
If v=140pc, the scale of the vertical axis in the figure is twice, so Qmax (+) = 406. 28pc,
Qmax(-)-274,54pc, Σ.

(+)=116240pc, Σq(-)-8024
It is 3pc. When the changes in these characteristics are graphed against the power application time, they are as shown in FIGS. 3 and 4.

FIG. 3 is a diagram showing changes in the maximum discharge charge Q wax of positive and negative polarities, and Q max does not change significantly for both positive and negative polarities from 20 hours to 375 hours after the start of charging. 38 suddenly without any clear signs of deterioration progressing.
Dielectric breakdown occurred after 4 hours.

Figure 4 shows changes in the total discharge charge Σq of positive and negative polarity, and the total discharge charge Σq of the discharge pulses generated per AC cycle increased up to 100 hours after the start of charging. Thereafter, it gradually increases until 350 hours, and then shows a rapid increase until 375 hours, leading to dielectric breakdown. Σ
The value of q itself varies depending on the number of samples, the shape of the sample, and various other factors, but by tracking its changes intermittently, it is possible to understand the progress of insulation deterioration and the signs immediately before dielectric breakdown, and to determine the degree of insulation deterioration. can be evaluated. That is, according to this embodiment, the state of insulation deterioration can be expressed accurately.

H1 Effects of the Invention As described above, according to the present invention, it is possible to provide an insulation diagnosis method for high voltage equipment that accurately expresses the state of insulation deterioration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a waveform diagram of an embodiment of the present invention, and FIGS. 3 and 4 are characteristic diagrams of partial discharge analysis results. DESCRIPTION OF SYMBOLS 1... Sample, 2... Transformer, 3... Detection part, 4...
...partial discharge measuring device, 5...first storage device, 6...
- Second storage device, 7...computer. Figure 1: Diagram of an axillary example of the present invention

Claims (1)

[Claims] (1) In an insulation diagnosis method for high-voltage equipment that detects, measures, and analyzes the waveform of a partial discharge pulse with a partial discharge measuring device installed on the sample, the first waveform stores the waveform of the voltage applied to the sample. A storage device, a second waveform storage device that stores the waveform of the detected partial discharge pulse, and a computer that analyzes the data. An insulation diagnostic method for high-voltage equipment, which is characterized by summing up the values and analyzing the insulation characteristics based on the total value.