JPS6131429B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a salt damage prediction device that detects deterioration in insulation resistance due to salt adhesion on an insulator.

Insulators used in power generation and substations, power transmission lines, and the like are subject to salt damage, that is, adhesion of salt, which can reduce their insulation resistance and cause flashover accidents. Therefore, it is necessary to predict salt damage and prevent accidents from occurring.

Conventionally, the method of predicting salt damage is to hang a pilot insulator near the site, wash off the salt adhering to it using a brush wash method, and measure the conductivity of the liquid to equivalently determine the salt adhesion. A method of measuring quantity is used. However, with this method, each time a measurement was taken, the pilot insulator had to be lowered from the top of the pillar and the salt adhering to the insulator had to be washed off using a brush washing method, making the measurement work very troublesome. . In addition, the insulator is washed after each measurement.
The surface will be new, and the next measurement will be inconveniently different from the accumulated amount of salt deposited on the insulator that is actually in use.

For this reason, instead of the pilot insulator, a spherical insulator is used to easily wash off the salt adhering to the insulator, and the salt adhering to the spherical insulator is washed off by pouring distilled water over it, and the liquid is collected in the chamber and accumulated. A method is sometimes used to equivalently display or record the amount of salt adhesion by measuring electrical conductivity. This measurement method was developed to solve the drawbacks of the brush-washing method described above, and is intended to facilitate automation of measurement. However, when the measurement is automated,
The configuration of the measuring device becomes complex, and regular inspections are required to maintain the performance of the device. Furthermore, since the device handles liquid, it is necessary to add a detailed heat insulating device during winter use. moreover,
Since a spherical insulator, which has a different shape from the actual insulator, is used instead of the pilot insulator, there is a problem in that a considerable error occurs in the measured values.

This invention was made in view of the above-mentioned circumstances, and it is possible to easily measure the state of salt adhesion on an actual insulator by using a pilot insulator while the insulator is installed in the same state as the actual insulator. The purpose of the present invention is to provide a salt damage prediction device configured as follows.

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings. Figure 1 shows its configuration.
A DC power supply 10 is provided. The output voltage of this power supply 10 is supplied to a capacitor 13 via a switch 11 and a current limiting resistor 12. A moisture-proof electrostatic voltmeter 14 is connected in parallel to this capacitor 13 to measure the terminal voltage E of the capacitor 13. This voltmeter 14
are provided with voltage value detection means 15a and 15b consisting of, for example, photoelectric converters. The detection means 15a detects that the measured value of the voltmeter 14 is the set value E1.
The detection means 15b generates a detection signal S1 when the set value E2 (E2<E1) is reached. These signals S
1 and S2 are supplied to the control circuit 16.

The control circuit 16 receives the supplied signals S1 and S.
2, the switch 11, a switching switch 17 (described later), and a counter 18 are driven and controlled. The control circuit 16 excites and controls the drive coil 11a of the switch 11. When a measurement command is given to the control circuit 16, the drive coil 11a is excited to close the switch 11. Then, when the detection signal S1 is generated, the excitation is released and the opening state is established. That is, when starting measurement, the capacitor 13 is charged with the output voltage of the power supply 10, and its terminal voltage reaches the set value E1.
When this happens, the power source 10 is disconnected.

The control circuit 16 further excites and controls the drive coil 17a of the switching type switch 17. . This switch 17 has a pair of contact circuits 17 that are reciprocally closed.
b, 17c, and the terminal voltage of the capacitor 13 is detected through the contact circuit 17b on the normally open side. The drive coil 17a is controlled so that it is excited when the control circuit 16 detects the signal S1, and demagnetized when the signal S2 is detected. Terminal voltage E of capacitor 13 taken out via contact circuit 17b
is connected to a measuring pilot insulator 20 via a current limiting resistor 19. This pilot insulator 20 is appropriately suspended near the site where the power transmission line insulator is present. That is, with the contact circuit 17b of the switch 17 closed, the charge in the capacitor 13 is discharged via the resistor 19 and the pilot insulator 20. The other contact circuit 17c connects the AC power supply 21 to the resistor 1.
9, so that AC power is supplied to the pilot insulator 20 during normal operation.

The counter 18 is designed to count the set clock signal, and has a function to output and display the counted value as appropriate. When the control circuit 16 detects the signal S1, it starts counting the clock signals and ends the counting when the signal S2 is detected, thereby measuring the time interval between the signals S1 and S2.

In the device configured in this way, in a steady state that is not a measurement state, the drive coils 11a, 17a of the switches 11, 17 are in a non-excited state, and their contact circuits are in the state shown in the figure. Therefore, the output voltage of the AC power supply 21 is supplied to the pilot insulator 20 via the resistor 19. This AC power supply 21 uses the pilot insulator 20 as an insulator (not shown) that is actually used.
The output voltage is set to almost the same voltage value as the voltage value of the electric wire to which the insulator is actually attached. This means that the insulator attached to the wire is
This was done in consideration of the fact that since the AC voltage of the wire is always applied, the condition of its surface is different from that of an insulator that has been left without any AC voltage applied.

During measurement, the switch 11 is closed by a command from the control circuit 16 corresponding to the measurement command, the capacitor 13 is charged by the DC power supply 10, and the terminal voltage E is as shown in FIG. increases over time. This terminal voltage E is the set value E1
When the voltage E1 is increased to 1, the voltage E1 measured by the voltmeter 14 is detected by the detection means 15a, and a command is given to the control circuit 16 to open the switch 11 and simultaneously excite the drive coil 17a of the switching switch 17. At the same time, counter 18 starts counting. That is,
The charge stored in the capacitor 13 is supplied to the resistor 19 via the contact circuit 17b, and is discharged via the pilot insulator 20. Therefore, the terminal voltage E of the capacitor 13 decreases with a time constant determined by the total resistance value of the resistor 19 and the insulator 20, as shown in FIG. and terminal voltage E
When the value decreases to the set value E2, a signal S2 is generated from the detection means 15b, and the counter 18 stops counting. Therefore, the counter 18
The discharge time T during which the terminal voltage of No. 3 decreases from E1 to E2 will be measured.

The discharge characteristics shown in FIG. 3 are logically expressed as E=E1.exp(-t/C.R'). Here, C indicates the capacitance of the capacitor 13, and R' indicates the resistance value of the discharge circuit. Since the capacitance of the pilot insulator 20 is small, it can be ignored by setting the capacitance C of the capacitor 13 to a sufficiently large value. Also,
Since the resistance value R of the pilot insulator 20 is extremely large compared to the resistance value of the resistor 19, it can be regarded as R〓R'. Therefore, the resistance value R of the pilot insulator is becomes. That is, the discharge time T counted by the counter 18 has a value proportional to the resistance value R of the pilot insulator 20. Therefore, by measuring at certain intervals and examining changes in the discharge time T,
Abnormalities in the insulation state of the pilot insulator 20 can be detected, and salt damage can be predicted. Moreover, if necessary, the resistance value R can be determined using the above-mentioned formula. For example, if the capacitance C of the capacitor is 0.1μF, and the set voltage value E1 is 5000V,
When E2 is 3000V and the measured discharge time T is 620.654ms, the resistance value R of the pilot insulator is calculated to be 12150MΩ.

Although the device of the above embodiment is configured to directly display or record the discharge time T, it is also possible to configure the device to display or record the resistance value R.

As explained above, the salt damage prediction device according to the present invention can be installed in the same state as the actual insulator.
This method directly measures the insulation condition of the pilot insulator. Therefore, the measurement accuracy is improved compared to the indirect measurement method of measuring the salt adhering to the pilot insulator and estimating its insulation state, as in the conventional salt damage prediction method. Furthermore, since it does not handle liquids such as distilled water, a heat insulating device is not required even when measuring in winter. Furthermore, the configuration of the device is relatively simple, and measurements can be carried out in an extremely short time and easily.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a salt damage prediction device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing changes in terminal voltage during charging of the capacitor shown in FIG. 1, and FIG. FIG. 3 is a characteristic diagram showing changes in terminal voltage during discharge of the capacitor. 10... DC power supply, 11... Switch, 12, 19...
Current limiting resistor, 13... Capacitor, 14... Electrostatic voltmeter, 15a, 15b... Voltage value detection means, 16
... Control circuit, 17... Switch type switch, 18... Counter, 20... Pilot insulator, 21... AC power supply.

Claims (1)

[Claims] 1. A capacitor that is charged to a specified terminal voltage in response to a measurement command, and a discharge circuit that is connected in parallel to this capacitor in a state where this capacitor is charged to the specified terminal voltage. a measuring pilot insulator, a means for detecting that the terminal voltage of the capacitor discharged through the pilot insulator has decreased to another specified value, and A salt damage prediction device characterized by comprising a means for measuring time. 2. The device according to claim 1, wherein the pilot insulator is provided with an AC power source that is always connected when not measuring.