JPH0479211B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a power source that supplies drive power to various measurement circuits by applying electricity to high voltage equipment such as a closed gas switch or a transformer. Regarding equipment.

(Technical Background of the Invention) FIG. 1 shows an example of a partial discharge measurement method in a closed gas switch. This switch is
The high-voltage section is covered with a metal casing 1 for closing, which is electrically divided in the longitudinal direction via insulating spacers 2. At its center, a center conductor 3 electrically connected to a power transmission line (not shown) is supported by a spacer 2 . The casing 1 is grounded by a grounding wire (not shown).

The spacer 2 is provided with an electrode 4 for voltage detection, and a capacitor 5 for partial discharge detection is connected between the electrode 4 and the casing 1. An electric-to-optical converter (hereinafter referred to as an E/O converter) 7 is connected to both terminals of the capacitor 5 via a signal lead-in line 6.

When a high voltage is applied to the center conductor 3, the stray capacitance _C1 existing between the center conductor 3 and the electrode 4 and the capacitor 5 form a voltage divider, and a shared voltage is generated across the capacitor 5. do. When a partial discharge occurs in the switch, a high frequency component caused by the discharge is superimposed on this shared voltage, so the high frequency component is separated in the E/O converter 7 and is converted into electricity and optical fiber 8
A partial discharge in the switch can be detected by transmitting the signal to a monitoring unit (not shown) via the switch.

(Problems with the background technology) Now, in such a partial discharge measurement method,
Conventionally, batteries, batteries, etc. have been separately connected or built into the E/O converter 7 as a power supply device, so it has been necessary to charge or replace these power supply devices in a short period of time.

Furthermore, since the partial discharge signal is a weak signal, if an external power source is used instead of a battery for the E/O converter 7, partial discharge cannot be detected accurately if noise enters through the power line. There was also a risk that the E/O converter 7 would be destroyed due to the intrusion of high voltage surges.

(Object of the Invention) An object of the present invention is to provide a power supply device that can supply the power necessary for driving various measurement circuits without performing charging or replacement work and with almost no influence of noise. It is about providing.

(Summary of the Invention) The present invention extracts part of the energy of an electric field generated by applying power to a high voltage device as a shared voltage, and rectifies this with a rectifier. Then, the output voltage from this rectifier is divided into two or more by a voltage dividing circuit. The measurement circuit is divided into two or more blocks, and each block is supplied with a voltage divided by the voltage dividing circuit.

The measurement circuit is used, for example, to measure partial discharge in the high voltage equipment.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows a part of a closed gas switch in which partial discharge is to be detected and a circuit configuration of a power supply device 9 according to the present invention. The switch is equipped with a center conductor 3 to which a high voltage is applied from a power transmission line (not shown) and is used for breaking the power transmission line, and a casing 1 of the switch.
are electrically divided in the longitudinal direction via spacers 2 made of an insulator.

The power supply device 9 of the present invention includes a detection electrode 4 provided on the spacer 2 and a capacitor 5 provided between the electrode 4 and the casing 1 as a shared voltage generating means. A rectifier 10 is connected to both terminals of the capacitor 5 via a lead-in line 6 for extracting an induced voltage containing high frequency components, and a voltage dividing circuit 12 is further connected to the rectifier 10. The rectifier 10 has a bridge type full-wave rectifier circuit configuration having a plurality of diodes 11.
The voltage dividing circuit 12 is constructed by connecting a plurality of voltage dividing parts in series, each of which is a combination of a Zener diode 13 and a capacitor 14 connected in parallel. On the other hand, the partial discharge measurement circuit 15
It consists of a high-frequency transformer 16 for detecting high-frequency components inserted in series with the high-frequency transformer 16, and an integrated circuit section into which the signal extracted from the high-frequency transformer 16 is input. The integrated circuit section includes an amplifier circuit 17 for amplifying the signal, and a diode 18 for transmitting the amplified signal.
Analog-to-digital (A/
D) A conversion circuit 19 and an LED (light emitting diode) 21 that amplifies the signal digitized by this circuit 19 with a transistor 20 and then converts it from electricity to light.
The optical fiber 8 is optically coupled to the LED 21. Then, the amplifier circuit 17 of the integrated circuit section
One voltage dividing section consisting of a Zener diode 13 and a capacitor 14 in the voltage dividing circuit 12 is connected as a power supply to the A/D converter circuit 1.
9 is connected to another voltage dividing section as a power source, and the remaining voltage dividing section is further connected to the transistor 20 and the LED 21 as a power source.

Next, the operation of the power supply device 9 of the present invention will be explained.
First, when a high voltage of commercial frequency, that is, 50 or 60 [Hz] is applied to the center conductor 3 from the power transmission line, the stray capacitance that occurs between the center conductor 3 and the electrode 4 increases.
_C1 and capacitor 5 constitute a voltage divider, and a shared voltage of 50 or 60 [Hz] is generated in capacitor 5.
This shared voltage is led to a rectifier 10 via a lead-in line 6, and the rectifier 10 rectifies it to a voltage dividing circuit 12.
A predetermined DC voltage is applied to the Since the voltage dividing circuit 12 divides this voltage using a voltage dividing section consisting of a combination of a plurality of Zener diodes 13 and a capacitor 14, each divided voltage is transmitted to the measuring circuit 15.
The power is applied to the amplifier circuit 17, A/D conversion circuit 19, transistor 20, and LED 21, respectively.

By the way, the induced voltage induced by the capacitor 5 has a high frequency component superimposed thereon, as shown in FIG. This high frequency component is generated due to partial discharge when a partial discharge occurs in the closed gas switch, and is superimposed on the induced voltage. Then, this high frequency component is extracted as a detection signal Vs by the high frequency transformer 16 for signal detection, and is input to the amplifier circuit 17 of the partial discharge measuring circuit 15.

Now, the amplifier circuit 17 is operated by a power supply voltage divided by the voltage divider circuit 12, and the detection signal Vs is amplified by the amplifier circuit 17, and the diode 1
8 to the A/D conversion circuit 19. This circuit 19 is also supplied with a divided voltage as a power supply, so the amplified detection signal
V ₁ is converted into a digital signal V ₂ and input to transistor 20 . And this transistor 2
Since a divided voltage is also applied to V 0 and LED 21, this digital signal V ₂ is further amplified and then converted into an optical signal by LED 21.
It is transmitted by optical fiber 8. Therefore, by analyzing the transmitted optical signal on the monitoring section (not shown) side, partial discharge in the switch can be detected. By the way, the amplifier circuit 17, the A/D conversion circuit 19, the transistor 20, and the LED 21,
As shown in FIG. 4, if they respectively correspond to blocks 1, 2, and 3 of the measuring circuit 15, the currents I ₁ , I ₂ , and I ₃ required for each block 1 to 3 are connected to Zener diodes. 13 Zener voltage. Therefore, by selecting appropriate Zener diodes, predetermined currents I ₁ , I 2 , and I 3 can be passed through each block 1 to 3, and the surpluses I _{1 ′} , I ₂ ′, and I _{3 ′} are It can be bypassed by a Zener diode 13 and a capacitor 14. For example, in the center conductor of high voltage equipment.
Assuming that a voltage of 300 [KV] is applied, in the actual circuit C ₁ = several [pF] capacitor 5 = 200
[pF], and the total current Imax = several hundred [μA]
In this case, it is preferable to use a Zener diode with a Zener voltage of about 5 to 10 [V].

In this way, if the induced voltage obtained by energizing a high voltage device is rectified and then divided, and each divided voltage is applied to each block of the measuring circuit 15, the surplus current is sequentially applied to the subsequent blocks. Since the current can be applied in series to each block, even the weak electric power obtained from the shared voltage generating means can supply enough current to each block to operate it.

In addition, the power supply device 9 of the present invention can be used as a power source for measuring instruments of high voltage equipment such as transformers and power transmission lines in addition to the above-mentioned embodiments.

In addition to partial discharge measurement circuits, various measurement circuits such as temperature measurement circuits can be considered as measurement circuits to which divided voltages should be applied, and even in these circuits, predetermined operation can be achieved by applying divided voltages to each block. can be made to do so.

(Effects of the Invention) According to the present invention, a shared voltage is generated by a capacitor or the like using electricity to a high-voltage device, and then this shared voltage is rectified and then divided, and each divided voltage is measured by a circuit. By igniting each block that requires each voltage, it is possible to effectively utilize this to operate the measurement circuit stably. Therefore, since an external power supply device such as a battery is not required, there is no need to perform charging or replacement work. Additionally, since power is extracted directly from high-voltage equipment, the effects of external noise can be almost completely eliminated. As a result, partial discharge and the like can be measured reliably and accurately.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a conventional partial discharge measurement method, FIG. 2 is a circuit diagram showing an example of application of the power supply device according to the present invention to partial discharge measurement, and FIG. 3 is a waveform diagram of induced voltage. FIG. 4 is a diagram showing each block of the partial discharge measuring circuit together with the flow of current. 1... Casing, 2... Spacer, 3... Center conductor, 4... Electrode, 5, 14... Capacitor,
6...Signal lead-in line, 7...E/O converter, 8...
Optical fiber, 9...power supply device, 10...rectifier,
12... Voltage dividing circuit, 13... Zener diode, 15... Partial discharge measuring circuit, 16... High frequency transformer, 17... Amplifying circuit, 19... A/D conversion circuit, 21... LED.

Claims (1)

[Scope of Claims] 1. A shared voltage generating means that generates a shared voltage by energizing high voltage equipment, a rectifier that rectifies the voltage across the shared voltage generating means, and at least two or more output voltages from the rectifier. What is claimed is: 1. A power supply device comprising: a voltage dividing circuit that divides the voltage between the two blocks and supplies the required voltage to each block of the measurement circuit. 2. The power supply device according to claim 1, wherein the measurement circuit is a partial discharge measurement circuit for measuring partial discharge generated in high voltage equipment.