JPS61150305A - Life diagnosing equipment for oil-filled electric apparatus - Google Patents

Abstract

PURPOSE:To made it possible to grasp the degree of deterioration of the insulation of the oil-filled electric apparatus and to diagnose its life, by monitoring always the temperature of the refrigerant in the oil-filled electric apparatus and the load condition, obtaining the representative temperature for deterioration of the oil-filled electric apparatus, and computing the time integral of the deterioration speed corresponding with the representative temperature. CONSTITUTION:The temperature of the refregerant 2 in the main tank 1 of the oil-filled electric apparatus is measured by the temperature detector 6. Based on this detected temperature and the detected signal by the load detector measuring the current in the circuit 5, the operation unit 7 produces the output signal corresponding with the representative temperature of the winding 3. Based on the signal from the unit 7, the operation unit 8 delivers the output signal corresponding with the deterioration speed of the insulator of the oil-filled electric apparatus 1 to the operation unit 9. The unit 9 computes the degree of deterioration by the time integral of the deterioration speed, and determines the life of the electric apparatus from the time when the degree of deterioration reaches the prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a lifespan diagnosis device that can diagnose the lifespan of oil-filled electrical appliances such as transformers and reactors.

[Technical background of the invention and its problems] In general, oil-filled electrical appliances such as transformers have recently become extremely high-voltage and large-capacity, so if an accident occurs, the social impact is very large.

Therefore, equipment that has been operated for a long time and whose mechanical and insulation strength has decreased due to aging of the insulator (equipment that has reached the end of its life),
It is necessary to replace the equipment with new equipment to prevent accidents.

It is said that the rate of deterioration of insulators is determined by the surrounding temperature, but since the ambient temperature of insulators varies depending on the installation conditions and load conditions of oil-filled appliances, and for each device and time, the rate of deterioration also varies. Not like that. Previously, oil-filled electrical appliances had a uniform lifespan of about 30 years, but depending on the load conditions
It is thought that there were some that had a low degree of deterioration and were sufficiently durable to be used even after 20 years of operation, and some that had deteriorated rapidly and reached the end of their service life even though they had not reached -3 years.

[Object of the Invention] Therefore, it is an object of the present invention to provide a lifespan diagnosing device for oil-filled appliances that can accurately grasp the degree of deterioration of the insulation of oil-filled appliances and thereby diagnose the lifespan of oil-filled appliances. With the goal.

[Summary of the Invention] In order to achieve the above object, the present invention constantly monitors the refrigerant temperature and load conditions of oil-filled appliances, determines a representative temperature related to deterioration of oil-filled appliances, and calculates the deterioration rate corresponding to this representative temperature. It is configured to perform time integration.

[Embodiments of the invention] Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. It is a schematic configuration diagram,
1 is the main body tank of the oil-filled power supply, 2 is the cooling medium, 3 is the winding wire, 4
is a main circuit connected in series to this winding; 5 is a load detector such as a current transformer that detects the current of this main circuit 4; and 6 is a temperature detector that measures the temperature of the cooling medium 2. 7 is an arithmetic device which obtains an output signal corresponding to the representative temperature of the winding m3 based on the signals from the load detector 5 and the temperature detector 6. 8 is a calculation device that obtains an output signal corresponding to the deterioration rate of the insulator based on the signal from the calculation device 7; 9 is a calculation device that integrates the signal from the calculation device 8 over the operating period of the oil-filled appliance and outputs a signal corresponding to the deterioration. It is a device for obtaining signals.

Next, an explanation will be given of the operation of the life diagnosis device for oil-filled electrical appliances according to the present invention configured as described above. As shown in FIG. 2, the temperature curve of the winding 3 is determined by equations (1) and (2).

θwi(t)−θoi(t)+θui(t)−・■θ
Wi: Temperature of the winding 3 θO1: Temperature of the cooling medium 2 θu1: Temperature rise of the winding 3 with respect to the cooling medium. If I is obtained by m and the temperature θO1 of the cooling medium 2 is obtained by the m degree detector 6, then the arithmetic unit 7 calculates
, ■By calculating the formula, the temperature θw of the winding 3 can be determined by
i can be obtained.

On the other hand, the relationship between the deterioration rate V of cellulose-based insulating materials currently used in oil-filled appliances and the ambient temperature of the insulating materials is the third
As shown in the figure, it is given by formula (■).

D = index expressing degree of deterioration (ratio of characteristic value to initial value D(0) = 1) V: deterioration rate CI, C2: constant determined by material Therefore, calculate the winding temperature θwi which is the output signal of the calculation device 7 The deterioration rate V can be obtained by inputting the data into the bag ft8 and performing calculations based on formula (2). Further, by time-integrating the deterioration rate V using the arithmetic unit 9, the degree of deterioration can be determined as shown in equation 0.

When the degree of deterioration determined in this way decreases to a predetermined value, it can be determined that the life of the device has been reached.

FIG. 4 is a schematic diagram showing another embodiment of the life diagnosis device for oil-filled electrical equipment according to the present invention. The configuration up to the calculation device 9 is the same as that shown in FIG. 1, but the lifespan can be determined by adding a calculation bag [10] that outputs an alarm signal when the degree of deterioration falls below a preset deterioration level Do. I can do it.

[Effects of the Invention] According to the present invention described above, the refrigerant temperature and load conditions of oil-filled appliances are constantly monitored, a representative temperature related to deterioration of oil-filled appliances is determined, and the deterioration rate corresponding to this representative temperature is integrated over time. As a result, it is possible to accurately grasp the degree of deterioration of the insulator of an oil-filled appliance, thereby providing a lifespan diagnosis device for an oil-filled appliance that can diagnose the lifespan of an oil-filled appliance.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an embodiment of the life diagnosis device for oil-filled electrical appliances according to the present invention, Fig. 2 is an explanatory diagram showing temperature changes in the winding of the embodiment, and Fig. 3 is an illustration of the temperature change of the winding of the embodiment. FIG. 4 is a diagram showing the relationship between deterioration of an insulating material and temperature, and is a schematic configuration diagram showing another embodiment of the life diagnosis device for an oil-filled electrical appliance according to the present invention. 1...Oil-filled electrical equipment tank, 5...Load detector, 6...
-Temperature detector, 7 to 10...Arithmetic device. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (2)

[Claims] (1) A step that calculates the representative temperature of the oil-filled appliance by inputting an output signal corresponding to the temperature of the cooling medium inside the body of the oil-filled appliance and an output signal corresponding to the current flowing in the main circuit of the oil-filled appliance. A first calculation device, a second calculation device that calculates the deterioration rate at the representative temperature determined by the first calculation device, and a degree of deterioration by integrating the deterioration rate determined by the first calculation device over time. A lifespan diagnosis device for oil-filled electrical appliances, comprising a third arithmetic device that obtains an output signal corresponding to. (2) The third arithmetic device outputs an alarm when the output signal corresponding to the degree of deterioration reaches a preset level. Lifespan diagnosis device.