JPH09152424A - Method for detecting generating position of maximum discharged amount of charges of high voltage insulation exciting coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect whether or not a position of the maximum discharged amount of charges is within a core slot, by using a correlation of the maximum discharged amount of charges and a maximum amplitude value of an acoustic emission(AE) parameter. SOLUTION: A simulation core 2 is fitted at a part corresponding to a core slot of an insulating exciting coil 1 to be tested. An AE sensor 3 is connected to an AE analyzer via a preamplifier. Before an insulation deterioration is given rise to, the maximum discharged amount of charges and a maximum amplitude value of an AE parameter of the insulating coil 1 are simultaneously measured with the use of a voltage as a parameter, thereby checking a correlation of the discharged amount and the maximum amplitude value. Then, when the maximum discharged amount changes after the coil is operated, it is detected whether or not a position where the maximum discharged amount of charges is generated is within the core slot of the insulating coil 1 from the correlation with the maximum amplitude value of the AE parameter measured at the same time as the maximum discharged amount of charges. In this manner, whether or not even a large value of the maximum discharged amount of charges results from a creeping discharge outside the core slot can be detected without a guard electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge position discriminating method for discriminating whether or not the position where the maximum discharge charge amount detected when high voltage is applied to a high voltage insulating coil is generated is in the slot of the insulating coil. It is a thing.

[0002]

2. Description of the Related Art When a high voltage is applied to a high-voltage insulating coil, a void discharge is generated from a void in a coil insulating layer, a slot discharge is generated between a core slot surface and an insulating coil surface,
A creeping discharge is generated from the surface of the insulated wire outside the end of the iron core slot. In order to suppress insulation deterioration due to slot discharge and creeping discharge on the surface of the high-voltage insulation coil, a low-resistance insulation layer is provided on the surface of the insulation coil that is inserted into the iron core slot. A semiconductive tape is tightly wound around the outer surface of the insulating coil to alleviate the electric field on the surface of the insulating coil.

In order to measure the partial discharge generated from the high voltage insulated coil, there are partial discharge measuring instruments using various electrical detection methods. The partial discharge measuring instrument by the electrical detection method detects and amplifies a minute pulse current due to partial discharge from the defective part, and can quantitatively measure the partial discharge pulse waveform, partial discharge occurrence frequency and partial discharge charge amount. . The detection sensitivity is high, and it is possible to detect minute partial discharges, but it is not possible to detect the position where partial discharges occur. Using these partial discharge measuring instruments, the creeping discharge generated from the outside of the iron core slot when a high voltage is applied to the insulated coil is removed, and only the void discharge and slot discharge generated inside the iron core slot are measured. As a general method, a creeping discharge is removed by attaching a guard electrode to an insulating coil outside the iron core slot and grounding the electrode.

[0004]

However, it is impossible to attach a guard electrode to the insulating wire ring when measuring partial discharge of the high voltage rotating machine insulating wire ring in an actual machine. On the other hand, the semi-conductive tape on the outermost layer of the insulated coil outside the iron core slot keeps the specified resistance value and suppresses the slot discharge at the time of new manufacturing, but it deteriorates due to deterioration during long-term use. A change occurs and creeping discharge easily occurs. Therefore, in the high voltage insulated wire loop of the actual machine, which seems to have deteriorated the insulation during long-term use, even if the large maximum discharge charge amount of the partial discharge measurement result is detected, the guard electrode is not attached. It was unclear whether the cause was void discharge or creeping discharge. The present invention was devised in view of the above points, and the purpose thereof is to determine whether or not a large maximum discharge charge amount is detected by performing partial discharge measurement without attaching a guard electrode, and whether it is due to creeping discharge. It is to provide a method of determining

[0005]

[Means for Solving the Problems] In other words, a means for achieving the object is a high-voltage insulated coil inserted into a slot of an iron core having an acoustic emission (hereinafter abbreviated as AE) sensor attached, By measuring the maximum discharge charge amount of the high-voltage insulated wire and the maximum amplitude value of the AE parameter at the same time using the voltage as a parameter before the insulation deterioration, and checking the correlation between them, the maximum discharge charge amount can be determined in the subsequent measurement. It is determined whether or not the position where the maximum discharge charge amount is generated is in the iron core slot of the insulating coil, from the correlation with the maximum amplitude value of the AE parameter that is measured at the same time when it changes.

Alternatively, in a high-voltage insulated coil inserted in a slot of an iron core to which an AE sensor is attached, the maximum discharge charge amount of the high-voltage insulated coil and the maximum amplitude value of the AE parameter are simultaneously measured using voltage as a parameter. Then, the correlation between the two is examined, and whether the position at which the maximum discharge charge amount occurs is in the iron core slot of the insulated wire loop is determined by whether the correlation changes in the middle.

[0007]

Next, the operation will be described. It is said that the AE from the void discharge is generated when the energy released by the discharge becomes a wave in the gas to press and expand the void wall. Therefore, there is a certain correlation between the maximum discharge charge amount due to the void discharge and the maximum amplitude value of the AE parameter, as shown in A of FIG. However, a creeping discharge outside the iron core slot releases a considerable part of the energy released by the discharge into the atmosphere, so that the maximum amplitude value detected by the AE sensor attached to the iron core becomes relatively small. Therefore, the relationship between the maximum discharge charge amount in the creeping discharge and the maximum amplitude value of the AE parameter is different from the correlation between the maximum discharge charge amount due to the void discharge and the maximum amplitude value of the AE parameter. Further, since the maximum discharge charge amount generally tends to be large in the creeping discharge generated by the deterioration of the semi-conductive tape, in this case, the maximum amplitude value of the AE parameter is relative to the measured maximum discharge charge amount. Becomes smaller. From the above description, if the relationship between the measured maximum discharge charge amount of the insulated wire and the maximum amplitude value of the AE parameter is the same as the previously obtained correlation, the measured maximum discharge charge amount is It is a void discharge, and if it is different, it is not a void discharge. If the maximum amplitude value of the AE parameter is relatively small with respect to the maximum discharge charge amount measured at this time, it is determined that the creeping discharge is from outside the iron core slot.

In some cases, it is not possible to obtain the correlation between the maximum discharge charge amount and the maximum amplitude value of the AE parameter in advance before the insulation deterioration of all of the insulating coils. In that case, the maximum discharge charge amount of the high voltage insulated wire and the maximum amplitude value of the AE parameter are measured at the same time by using the voltage as a parameter, and the correlation between the two is investigated, and whether the correlation changes in the middle, It is determined whether or not the position where the maximum amount of discharged charge is generated is in the iron core slot of the insulated wire. The correlation between the two is usually a linear relationship unless there is a creeping discharge outside the iron core slot, so if it deviates from this linear relationship, it can be determined that the creeping discharge is outside the iron core slot. An embodiment of the present invention will be described in detail below with reference to the drawings.

[0009]

EXAMPLE FIG. 1 is a perspective view showing a state in which a simulated iron core having an AE sensor fixed thereto is attached to a high-voltage insulated wire wheel, and a test insulated wire wheel 1 is a synchronous generator stator insulated wire wheel rated at 13.8 kV. The simulated iron core 2 is attached to the portion corresponding to the iron core slot portion. A low resistance insulating layer L is provided on the iron core slot portion on the surface of the insulating loop, and a semiconductive tape S is closely wound around the outer end of the iron core slot. AE sensor 3 is 1
It has a resonance of 50 kHz and is connected to an AE analyzer through a preamplifier (not shown) through silicone grease.
The relationship between the "maximum discharge charge amount and the maximum amplitude value" before the insulation deterioration of the high-voltage insulation coil is shown in A of FIG. When the maximum discharge charge amount is set to a logarithmic value and the maximum amplitude value is displayed in dB and plotted, the correlation between the two becomes a straight line. A low-frequency type was used as the partial discharge measuring instrument for obtaining the maximum discharge charge amount, and the specimen detection method was used as the measuring circuit.

The above-mentioned insulated wire loop was subjected to continuous high-voltage application and forced insulation deterioration, and then the maximum discharge charge amount of the partial discharge characteristic and the maximum amplitude value of the AE parameter were measured. The correlation is as shown in B of FIG. 2. At point b, the maximum discharge charge amount is about 40,000 pC, and the maximum amplitude value of AE is 61d.
B. In FIG. 2, point b deviated from the straight line showing the correlation before insulation deterioration. Therefore, we investigated from which position of the insulated wire this large discharge occurs.
A method of measuring the discharge state of the high-voltage insulated coil in a non-contact manner is shown in the explanatory view of FIG. For the measurement, a German LD company Remke probe 4 was used, and the relative discharge level of each part of the high-voltage insulated coil was measured by a non-contact detection method using a C-sensor 5. Since the REMKE probe detects and measures the radiated electromagnetic wave generated by the discharge, it is possible to measure the relative discharge level with a capacitive C-sensor in both creeping discharge in the atmosphere and void discharge in the insulator. For that purpose, the simulated iron core 2 of the insulated coil was removed, and instead, a thin metal stranded wire 6 was wound around the iron core slot portion to ground the twisted tip end and the wire end. FIG. 4 shows the relationship between the “relative discharge level and the position of the insulating coil”, which was obtained by measuring the discharge state of the high-voltage insulating coil without contact. As a result, it was found that the discharge level was higher in the portion outside the slot than in the iron core slot of the insulated wire.

Even in the case of an actual machine in which the guard electrode cannot be attached to the insulating coil, if the correlation between the maximum discharge charge amount and the maximum amplitude value is obtained, the maximum discharge charge amount is generated as in the above embodiment. It is possible to determine whether or not the position to be in is in the iron core slot of the insulated wire.

[0012]

As described above, according to the present invention, even when a large maximum discharge charge amount is detected even when there is no guard electrode in the partial discharge measurement of the high-voltage insulated coil incorporated in the actual machine, It is possible to determine whether or not is due to a creeping discharge outside the iron core slot.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a simulated iron core having an AE sensor fixed thereto is attached to a high-voltage insulated wire loop.

FIG. 2 is a graph showing a relationship between “maximum discharge charge amount and maximum amplitude value” before insulation deterioration of a high-voltage insulated wire.

FIG. 3 is an explanatory view of a method for measuring the discharge state of a high-voltage insulated wire in a non-contact manner.

FIG. 4 is a graph showing the relationship between “relative discharge level and position of insulating coil”, which is obtained by measuring the discharge state of the high-voltage insulating coil without contact.

[Explanation of symbols]

 1 High voltage insulated wire loop 2 Simulated iron core 3 AE sensor 4 Remke probe 5 C-sensor 6 Thin metal stranded wire

Claims (2)

[Claims] 1. A high-voltage insulated coil is obtained by applying a predetermined voltage before insulation deterioration and simultaneously measuring the maximum discharge charge amount and the maximum amplitude value of acoustic emission parameters of the high-voltage insulated coil. From the difference between the correlation between the two and the correlation between the maximum discharge charge amount and the maximum amplitude value of the AE parameter obtained after the same measurement as before the insulation deterioration after the operation, the position where the maximum discharge charge amount occurs is isolated. A method for determining the maximum discharge charge amount generation position of a high-voltage insulated wire, which is characterized by determining whether or not it is inside the iron core slot of the wire. 2. In a high-voltage insulated coil, a predetermined voltage is applied to simultaneously measure the maximum discharge charge amount of the high-voltage insulated coil and the maximum amplitude value of the acoustic emission parameter to examine the correlation between the two. , The correlation is linear or non-linear, and it is determined whether or not the position where the maximum discharge charge amount is generated is in the iron core slot of the insulated wire loop. Quantity generation position determination method.