JPH0792481B2 - Gas-insulated sealed electric appliance voltage and partial discharge detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a gas-insulated closed switchgear (hereinafter abbreviated as GiS) to which a measuring device such as a photovoltage transformer and a partial discharge measuring device is attached. The present invention relates to a voltage and partial discharge detection device for gas-insulated sealed electric appliances such as electric appliances.

[Conventional technology]

In gas-insulated electric appliances, miniaturization and insulation reliability maintenance monitoring are important issues, and voltage transformers (P
T), current transformer (CT), etc. are also being developed from the conventional electromagnetic type to high voltage transformer (hereinafter abbreviated as optical PT) using Pockels effect element or CT using Faraday effect element. It is becoming possible to reduce the size of the voltage and current detectors that are internally or externally installed in such tanks. On the other hand, continuous monitoring of partial discharge is drawing attention as an effective method for maintaining insulation reliability, and in this case also, the important point is how to configure the partial discharge detection unit that is less affected by external noise. The detection electrode is provided inside the closed container, or the detection electrode is embedded in the insulating spacer that supports the charging part, and the partial discharge pulse included in the charging stream flowing to the ground through the detection electrode is applied to the outside of the closed container. The method of detecting by the detection impedance provided in the is promising.

4 and 5 show optical PT using Pockels effect element.
FIG. 4 is a configuration diagram including a partial cross-sectional view showing a GiS equipped with the detection unit, FIG. 4 shows an example of a single-phase gas bus bar, and FIG. 5 shows an example of a three-phase batch bus bar. . The In Figure 4, GIS1 the hand hole 5 is provided in the closed vessel 2 made of grounded metal that collection of SF ₆ gas 4 as the high voltage conductor 3 and the insulating gas directing large current, insulation on the cover plate 5A The intermediate electrode 7 which is airtightly supported via the member 6 is arranged such that its electrode surface faces the high-voltage conductor 3 with a predetermined distance, so that the intermediate electrode 7 is interposed between the high-voltage conductor 3 and the intermediate electrode 7. Capacitance C ₁ is generated. The intermediate electrode 7 is grounded through the capacitance C ₂ becomes divider capacitor 8, the capacitance C ₁ and
By choosing the ratio of C ₂ appropriately, shared voltage-divider capacitor C ₂ is set to be several tens to several hundreds V. Reference numeral 11 is a voltage sensor using the Pockels effect element 14. Since the transmittance of light changes when the sharing of the voltage dividing capacitor 8 is applied to the Pockels effect element 14, the LED light source unit 18 transmits the optical fiber 16A and the polarizer 12 to each other. , The transmission light transmitted to the Pockels effect element 14 via the 1/4 wavelength plate 13 and transmitted through the Pockels effect element 14 is separately arranged via the optical fiber 16B having the analyzer 15 and the lens 17. The applied voltage can be known by inputting it to the photodiode. Further, the voltage dividing capacitor 8 and the voltage sensor 11 are housed in a shield case 10 that is provided so as to project from or close to the closed container 2, and the influence of external light noise is eliminated. Also, when GiS is a three-phase device, as shown in FIG. 5, a ring-shaped guard electrode 27 is added to the intermediate electrode 7 arranged facing the high voltage conductor 3A, and this is directly grounded. , The only difference is that the charging current is bypassed from the high voltage conductors 3B, 3C of the other phase to the ground side through the guard electrode 27, and the influence of the potential of the other phase is avoided.
Others are the same as those described with reference to FIG.

[Problems to be solved by the invention]

Even in the GiS partial discharge monitoring device, by providing an electrode for detecting partial discharge in the closed container 2 so as to face the high voltage conductor 3, the partial discharge pulse is utilized by utilizing the electromagnetic shielding function of the grounded closed container 2. It is known that it is possible to avoid the influence of external noise that hinders the detection of the electric discharge. Therefore, it is considered appropriate that there is an idea that the intermediate electrode in the optical PT also serves as the electrode for detecting partial discharge. However, since their purposes and the types of signals to be handled are so different, it is known only that they are provided in separate places independently of each other. It requires a plurality of hand holes, and further requires a plurality of shield cases for electromagnetically shielding the detection section, signal line piping, and the like, which causes a significant economic disadvantage.

An object of the present invention is to make the structure of the device simple by sharing the detection electrode without adversely affecting the voltage measurement accuracy and the partial discharge detection accuracy.

[Means for solving problems]

In order to solve the above-mentioned problems, according to the first invention, a high-voltage conductor that guides a large current and a high-voltage conductor are insulated and supported in the closed container so as to face the high-voltage conductor. Intermediate electrode, and a voltage dividing capacitor connected to the intermediate electrode by an insulating lead that hermetically penetrates the sealed container, a detection impedance for detecting a partial discharge pulse included in the charging current of the voltage dividing capacitor, and the voltage dividing voltage. In a voltage and partial discharge detection device of a gas-insulated sealed electric appliance having a voltage sensor including a Pockels effect element having a shared voltage of a capacitor as an input signal, the detection impedance is a ground terminal and a terminal of the voltage dividing capacitor opposite to the intermediate electrode side. And the detection impedance is higher than the impedance of the voltage dividing capacitor with respect to the commercial frequency. It shall consist of resistance or inductance having had impedance.

According to the second invention, an intermediate electrode insulated and supported by the hermetically sealed container so as to face the high voltage conductor in a hermetically sealed container containing a high voltage conductor for guiding a large current and an insulating gas, and an intermediate electrode therebetween. The voltage dividing capacitor connected to the electrode by an insulating lead that hermetically penetrates the sealed container, the detection impedance for detecting the partial discharge pulse included in the charging current of the voltage dividing capacitor, and the voltage shared by the voltage dividing capacitor are input signals. In a voltage and partial discharge detection device of a gas-insulated hermetic electric appliance having a voltage sensor including a Pockels effect element, and the detection impedance is connected between a ground terminal and a terminal opposite to the intermediate electrode of the voltage dividing capacitor. The intermediate electrode is a disk-shaped electrode having a guard ring surrounding the outer periphery thereof, and the guard ring is the detection electrode. It shall be conductively connected to the ungrounded side of the impedance.

[Action]

In the above means, while the voltage to be measured for the optical PT is mainly the commercial frequency, the main frequency component of the partial discharge pulse to be measured by the partial discharge monitoring device is on the order of several hundred MHz, and L, C , R even after the waveform is converted to the low frequency side by the detection impedance composed of a series-parallel circuit, there is a large difference in the frequency range handled by both, and the transmission signals of both have optical and electrical characteristics. Focusing on the fact that there is a difference from the pulse, it is constructed on the basis of the idea that this difference is used conversely for simplification and sharing of the detection unit structure. That is, since the intermediate electrode for the optical PT is also used as the partial discharge detection electrode, the influence of external noise is eliminated and the structure of the detection unit is simplified. Further, a voltage dividing capacitor and a series body of the partial discharge detection impedance are connected to the intermediate electrode so that one end of the detection impedance is grounded. According to the first aspect of the invention, since the voltage dividing capacitor has a low AC resistance with respect to a partial charging pulse having a high frequency component, it does not hinder the detection of partial discharge, and the detection impedance is low when the optical PT is low. Since it is composed of a resistor or a coil having an impedance sufficiently lower than the impedance of the voltage dividing capacitor with respect to the frequency voltage, it does not affect the voltage shared by the voltage dividing capacitor, so that the measurement accuracy is not hindered by each other. Voltage and partial discharge pulses can be detected.

Further, according to the second invention, the intermediate electrode is a disc-shaped electrode having a guard ring surrounding the outer peripheral side thereof,
By configuring the guard ring to be conductively connected to the non-grounded side of the detection impedance, the partial discharge pulse flowing to the detection impedance is increased without affecting the shared voltage of the voltage dividing capacitor, and the partial discharge The detection sensitivity can be increased.

Further, in both the first invention and the second invention, since the detection signal and the transmission signal have a difference between light and electric pulse, there is no mutual interference, and the voltage dividing capacitor, the detection impedance, and the voltage sensor are shielded by the same shield. It can be housed in a case, and the transmission circuit consisting of optical fiber and coaxial cord can be housed in the same conduit.

[Examples] The present invention will be described below based on Examples.

FIG. 1 is a configuration including a partial cross-sectional view showing a device of an embodiment of the first invention, and shows an example of application to a single-phase device, and the same parts as those of the conventional device are designated by the same reference numerals for details. Will be abbreviated. In the figure, an intermediate electrode 7 is airtightly supported by a cover plate 5A of a handhole 5 via an insulating material 6 so as to face the high voltage conductor 3 of GiS1, and a voltage dividing capacitor 8 and a partial discharge detection electrode are used for this. A series body of detection impedances 31 composed of resistance or inductance is connected, and one end of the detection impedances is grounded. In addition, the shared voltage of the voltage dividing capacitor 8 is applied between both terminals of the Pockels effect element 14 of the voltage sensor 11, and the polarizer of the voltage sensor 11 is applied.
12 is optically coupled to the LED light source 18 separately arranged via the optical fiber 16A, and the analyzer 15 is optically coupled to the light receiving element of the operational amplification section 19 separately arranged via the optical fiber 16B to form the optical PT. To be done. On the other hand, the detection impedance 31 is conductively connected to a partial discharge measuring device or a partial discharge monitoring device 33, which is separately arranged via a coaxial cord 32, to measure the magnitude and frequency of occurrence of the partial discharge pulse detected by the detection impedance 31. To be done. In addition, main components such as the voltage dividing capacitor 8, the voltage sensor 11, and the detection impedance 31 are housed in a common shield case 30 to eliminate the influence of external light and external electrical noise.

In the embodiment apparatus configured as described above, when an AC high voltage is applied to the high-voltage conductor 3, the electrostatic capacitance C ₁ between the high-voltage conductor 3 and the intermediate electrode 7 and the static capacitance of the voltage dividing capacitor 8 are eliminated. The charging current for charging the capacitance C ₂ can flow to the ground side through the detection impedance 31, but the resistance value or the inductance of the detection impedance 31 is set to a low impedance Zd so that the voltage drop caused by the charging current at the commercial frequency is 1 V or less. By being selected, the shared voltage of the voltage dividing capacitor 8 is determined by the capacitance voltage dividing ratio C ₁ / C ₂ , and the voltage is measured by the optical PT with almost no influence of the detection impedance 31 arranged in series. be able to. Also, Gi
Assuming that partial discharge occurs on the S1 side, the partial discharge pulse is superimposed on the charging current and flows to the ground side through C ₁ , C ₂ , and the detection impedance 8, but for partial charging pulses with high frequency The capacitances C ₁ and C ₂ show low AC resistance, while the detection impedance Zd consisting of resistance or inductance shows high AC resistance on the contrary, so the partial discharge pulse gives a large voltage drop to the detection impedance 31,
Partial discharge can be detected with almost no influence of the series arrangement of the voltage dividing capacitors 8.

Further, since there is a qualitative difference between the light and the electric pulse and a large difference in the frequency region between the detection signals of both, even if the detection units are housed in the common shield case 30, they do not interfere with each other, and Since the cords coaxial with the fibers do not interfere with each other even if they are housed in a single conduit, the structure of the device can be simplified and the structure of the device can be greatly simplified by sharing the intermediate electrode 7.

FIG. 2 is a block diagram showing an embodiment of the second invention, showing an application example to a three-phase device. In the case of the figure, the point that the guard electrode 27 is insulated from the closed container 2 by the insulating material 6A, its terminal portion is drawn out, and is connected to the non-grounded end of the detection impedance 31 is different from the above-mentioned embodiment. , The charging current flowing from the other high voltage conductors 3B and 3C to the guard electrode 27 bypasses the voltage dividing capacitor 8 and detects the detection impedance 31.
Since the partial discharge pulse flowing to the detection impedance can be increased without affecting the divided voltage of the voltage dividing capacitor 8, the detection sensitivity of the partial discharge can be increased.

FIG. 3 is a configuration diagram showing a different embodiment of the second invention, which is different in that the guard electrode 27 is connected to the detection impedance via the capacitor 38, and a method of setting the capacitance of the capacitor 38. By the intermediate electrode 7 and the guard electrode
There is an advantage that the function as the guard electrode can be enhanced by holding 27 at the same potential.

〔The invention's effect〕

In the first invention, as described above, the intermediate electrode for the optical PT is also used as the partial discharge measuring electrode, and the voltage dividing capacitor for the optical PT and the detection impedance of the partial discharge are connected in series to this electrode to form a high voltage conductor. In the configuration configured to form the charging current path from No. 1, the detection impedance is a resistance or an inductance having an impedance lower than the impedance of the voltage dividing capacitor with respect to the commercial frequency. As a result, the voltage difference between the detection voltage of the optical PT and the partial discharge pulse and the difference in the quality of the optical signal and the electric pulse signal are used to measure the voltage and detect the partial discharge without the interference of external noise. It can be performed with the influence removed.

In the second invention, as described above, the intermediate electrode for the optical PT is also used as the partial discharge measurement electrode, and the voltage dividing capacitor for the optical PT and the detection impedance of the partial discharge are connected in series to this electrode to increase the voltage. In a structure configured to form a charging current path from a voltage conductor, the intermediate electrode is composed of a disc-shaped electrode having a guard ring surrounding the outer peripheral side thereof, and the guard ring is electrically conductive to a non-ground side of the detection impedance. With the configuration in which they are connected, it is possible to increase the partial discharge pulse flowing in the detection impedance without affecting the voltage shared by the voltage dividing capacitor, and to enhance the detection sensitivity of the partial discharge.

Further, in both the first invention and the second invention, by sharing the electrodes, the number of electrodes and the number of handholes are reduced, the structure of the detecting unit is simplified, and the shielding case and the transmission pipe can be shared. Therefore, it is possible to economically advantageously provide a gas-insulated closed electric appliance having a small-sized and simplified voltage and partial discharge detection unit structure. In addition, since the number of handholes is reduced by sharing the electrodes, the number of places where gas can leak is also reduced. Therefore, there is an advantage that the reliability of the gas insulated electric appliance can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment device of the first invention, FIG. 2 is a configuration diagram showing an embodiment device of the second invention, and FIG.
FIG. 4 is a block diagram showing an apparatus according to another embodiment of the invention, and FIGS. 4 and 5 are block diagrams showing a conventional apparatus. 1 ... GiS, 2 ... closed container, 3 ... high-voltage conductor, 4 ...
… Insulating gas, 5 …… Pocket part, 6,6A …… Insulating material, 7…
… Intermediate electrode, 8 …… Voltage-dividing capacitor, 10 …… Shield case, 11 …… Voltage sensor, 14 …… Pockels effect element,
16A, 16B …… Optical fiber, 27 …… Guard electrode, 30 …… Common shield case, 31 …… Partial discharge detection impedance, 32 …… Coaxial cord, 33 …… Partial discharge measuring instrument, 38…
… Capacitor, C ₁ , C ₂ …… Capacitance, Zd …… Impedance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H02H 7/00 F H02B 13/06 C

Claims (3)

[Claims] 1. An intermediate electrode insulated and supported by the hermetically sealed container so as to face the high voltage conductor in a hermetically sealed container containing a high voltage conductor for conducting a large current and an insulating gas, and a hermetically sealed container for the intermediate electrode. A voltage dividing capacitor connected by an insulating lead penetrating airtightly, a detection impedance for detecting a partial discharge pulse included in the charging current of the voltage dividing capacitor, and a Pockels effect element using the shared voltage of the voltage dividing capacitor as an input signal. In a voltage and partial discharge detection device of a gas insulated hermetic electric appliance having a voltage sensor including, the detection impedance is connected between the ground terminal and the anti-intermediate electrode side terminal of the voltage dividing capacitor, the detection impedance is A resistor having an impedance lower than that of the voltage dividing capacitor with respect to a commercial frequency, or Gas insulated sealed collector voltage and partial discharge detection apparatus, comprising the inductance. 2. An intermediate electrode insulated and supported by the hermetically sealed container so as to face the high voltage conductor in a hermetically sealed container containing a high voltage conductor for conducting a large current and an insulating gas, and a hermetically sealed container for the intermediate electrode. A voltage dividing capacitor connected by an insulating lead penetrating airtightly, a detection impedance for detecting a partial discharge pulse included in the charging current of the voltage dividing capacitor, and a Pockels effect element using the shared voltage of the voltage dividing capacitor as an input signal. In a voltage and partial discharge detection device of a gas insulated hermetic electric appliance having a voltage sensor including, the detection impedance is connected between the ground terminal and the non-intermediate electrode side terminal of the voltage dividing capacitor, the intermediate electrode is It is composed of a disk-shaped electrode having a guard ring surrounding the outer peripheral side thereof, and the guard ring has the detection impedance of Voltage and partial discharge detection device for a gas insulated switchgear collector, characterized in that it is conductively connected to the ground. 3. The voltage and part of a gas-insulated sealed electric appliance according to claim 2, wherein the guard ring is connected to the detection impedance via a capacitor that adjusts its potential. Discharge detection device.