JPH08146067A - Deterioration detection device of lightning arrester for ac/dc converter - Google Patents

Abstract

PURPOSE: To accurately detect deterioration and to eliminate the need for binoculars by mainly providing a resistance detector, a sensor part, a measurement part, and a deterioration detector. CONSTITUTION: A current increment signal corresponding to the increment is detected, where the resistance current out of leakage current increases along with the deterioration of lightning arresters 51 and 53 between A and K based on a voltage signal corresponding to the leakage current of the lightning arresters 51 and 53 between A and K of an arm with the same phase and control angle. And, the deterioration can be detected according to the current increment signal, thus accurately detecting deterioration regardless of the waveform of a voltage applied to the lightning arresters 51 and 53 between A and K. Also, the indication values of voltmeters 113a, 133a, and 151e can be directly and visually inspected on the ground rather than at a high location for a measurement parts 113 of an optical fiber voltage measuring instrument and a deterioration detector 151, thus eliminating the need for using binoculars.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deterioration detector for a surge arrester for an AC / DC converter which detects characteristic deterioration of a zinc oxide type arrester applied to a forward converter and an inverse converter of a DC transmission converter station.

[0002]

2. Description of the Related Art FIGS. 7 and 8 are a single-line electric circuit diagram showing a circuit structure of a conventional DC power transmission inverse conversion station disclosed in Japanese Patent Laid-Open No. 6-181109, and A- which is not shown in FIG. It is an electric circuit block diagram which shows the deterioration detection apparatus of the lightning arrester between K. In FIG. 7, 1 is a busbar of a three-phase AC system, 2 is a transformer for transformers in which both the primary side and the secondary side connected to the busbar 1 are star-shaped, and 3 is a star-shaped star-shaped secondary side connected to the busbar 1, secondary Transformer transformer 4 with side triangular connection is composed of each three-phase bridge connection on the high-voltage side and low-voltage side, and is a thyristor valve that constitutes a six-phase bridge connection rectification circuit by connecting to transformers 2 and 3 for the converter, respectively.
Each thyristor valve corresponds to each arm of this rectifier circuit. Reference numeral 5 is an AK lightning arrester that is connected in parallel to each thyristor valve 4 to protect the surge voltage and uses a zinc oxide type lightning arrester. Reference numeral 6 is a bridge arrester which is connected in parallel to the DC side terminals of the high-voltage side and low-voltage side three-phase bridge connections, and which uses a zinc oxide type arrester for surge voltage protection. Reference numerals 7a and 7b denote high-voltage side and low-voltage side DC lines connecting an inverse converter including a thyristor valve 4, an A-K lightning arrester 5, a bridge lightning arrester 6 and the like. Next, in FIG. 8, 9 is a switch connected in series to the AK lightning arrester 5, 11 is a non-linear resistance connected in parallel to the switch 9, and when the AK lightning arrester 5 operates, the overvoltage due to the surge current is counted. It is limited to 100 volts and shows a sufficiently high resistance value when it does not operate. Reference numerals 12 and 13 each form a low-pass filter with a capacitor and a resistor to bypass a high-frequency spike current generated when the forward and reverse voltage applied to the thyristor valve 4 changes stepwise. Reference numeral 14 is a Zener diode for limiting the overvoltage, which is limited to several hundred volts by the non-linear resistor 11, to several volts.
If the -K lightning arrester 5 does not operate, it shows a sufficiently high resistance value. An ammeter 15 measures the leak current of the AK lightning arrester 5. In addition, the deterioration detection device is a non-linear resistor 11, a capacitor 12, a resistor 13, a Zener diode 14, an ammeter.
8 and as an example, P ₁ -P in FIG.
_The deterioration detecting device and the switch 9 attached to the AK lightning arrester 5 of ₂ are shown, but P ₂ -P ₃ , P ₃ -P ₄ , P of FIG.
₄ Each A-K between arrester -P ₅ 5 and P ₁ -P _3, P
Similarly, each of the _3- E bridge arresters 6 is also provided with a deterioration detecting device and a switch 9.

The conventional deterioration detecting device for a surge arrester for an AC / DC converter is configured as described above, and AC / DC conversion is performed by controlling the control angle of the thyristor valve 4 while adjusting the direction and magnitude of the power flow. Since the thyristor valve 4 is weak against surge voltage and cannot be recovered when it is broken down, the thyristor valve 4 constitutes a non-linear resistance as an AK lightning arrester 5 in parallel with the thyristor valve 4 which constitutes each arm of the six-phase bridge connection rectifier circuit. Zinc oxide type arrester using the zinc oxide element of the body is connected, and also the zinc oxide type arrester is connected as a bridge arrester 6 in parallel to the rectifier circuit of each three-phase bridge connection on the high voltage side and the low voltage side to obtain surge voltage. Protect. The switch 9 is always closed. AK
A voltage in the reverse direction of the thyristor valve 4 is always applied to the lightning arrester 5, and a DC line is always applied to the bridge arrester 6.
About half of the voltage of 7a and 7b is applied, which causes leakage current, and if used for a long time, the zinc oxide element deteriorates and leakage current increases. Therefore, the switch 9 is opened when the operation of the conversion station is stopped by the inspection of the thyristor valve 4 which is regularly performed, the control angle of the thyristor valve 4 is set to a predetermined value, and the operation of the converter is restarted. The leakage current of the lightning arrester 5 is made to flow through the capacitor 12, the resistor 13, and the ammeter 15. The capacitor 12 and the resistor 13 form a low-pass filter to bypass the spike current of high frequency generated when the forward and reverse voltages applied to the thyristor valve 4 change stepwise, so that the ammeter 15 has a leakage current of a commercial frequency component. Flows and indicates the leakage current of the AK lightning arrester 5.
The indication value of the ammeter 15 at this time is visually observed from the ground with binoculars. Then, the leakage current is measured for each AK lightning arrester 5. Further, the same applies to each bridge arrester 6. The leakage current value thus measured is compared with the initial value to determine the deterioration of the zinc oxide arrester. When the measurement of the leakage current is finished, the operation of the converter is stopped, the switch 9 is closed, and the normal operation is started. When the surge arrester 5 between A and K operates and a surge current flows, the voltage applied across the nonlinear resistance 11 is limited to several hundred volts, and the voltage across the Zener diode 14 is limited to several volts. Then, the ammeter 15 is protected from the surge voltage. The resistor 13 also has a function of limiting the surge current flowing through the Zener diode 14 to prevent its destruction.

[0004]

The conventional device for detecting deterioration of a surge arrester for an AC / DC converter is constructed as described above, and since a zinc oxide type arrester is used for the AK lightning arrester 5 and the bridge lightning arrester 6, oxidation is prevented. The leakage current increases as the zinc element deteriorates. This leakage current is a combination of the resistance component current due to the non-linear resistance of the zinc oxide element and the capacitance component current due to the electrostatic capacity specific to the zinc oxide element.If the zinc oxide element deteriorates, the resistance component current increases. , The current for the capacitance hardly changes. The leakage current can reach 100 times the resistance current when compared with the peak value.It is extremely inaccurate to measure the leakage current to determine the deterioration of the zinc oxide type arrester, and the leakage current is measured. To do this, the conversion station must be shut down and the ammeter 15
There is a problem to be solved, such as having to visually check the indicated value of the ammeter 15 with binoculars, because is at a high place of the electricity application part.

The present invention has been made to solve the above problems, and it is possible to detect deterioration with high accuracy based on the resistance component current of the leakage current of the zinc oxide type arrester, and at the same time the conversion station. It is an object of the present invention to provide a deterioration detecting device for a surge arrester for an AC / DC converter, which can detect deterioration without stopping the operation of the device, while constantly monitoring the deterioration, and which does not require the use of binoculars.

[0006]

SUMMARY OF THE INVENTION A deterioration detecting device for a surge arrester for an AC / DC converter according to the present invention has two three-phase bridge connections connected in series and connected to two secondary windings having different phases of a converter transformer. The six-phase bridge connection rectifier circuit is formed by connecting two units of one-unit six-phase bridge connection in series, and the AK arrester is connected in parallel to the thyristor valve corresponding to each arm of the six-phase bridge connection rectifier circuit. In the arrester for AC / DC converter using the zinc oxide type arrester for the K arrester,
A resistance detector that detects a voltage signal corresponding to the leakage current of the lightning arrester between AK, a sensor unit that converts this voltage signal into an optical signal by utilizing the electro-optical effect, and a light beam that serves as a light source of this sensor unit is generated. In addition, an optical fiber voltage measuring device consisting of a measuring unit that converts an optical signal and outputs a voltage signal for display, and an optical fiber cable that transmits an optical beam and an optical signal between the measuring unit and the sensor unit, the same phase Based on the voltage signal from each optical fiber voltage measuring device belonging to the two arms, the current increment signal corresponding to the increase due to the deterioration of the AK arrester is detected and displayed by the resistance current included in the leakage current. It is equipped with a deterioration detector.

[0007] Also, two 3-phase bridge connections are connected in series, and two 6-phase bridge connections of one unit constituted by connecting to two secondary windings having different phases of a transformer for a converter are used.
A bridge arrester is connected in parallel to the DC side terminal of each three-phase bridge connection of a six-phase bridge connection rectifier circuit that is connected in series, and a bridge arrester using a zinc oxide type arrester is used in this arrester. A resistance detector that detects the voltage signal corresponding to the leakage current of the lightning arrester, a sensor unit that converts this voltage signal into an optical signal by using the electro-optical effect, and a light beam that serves as the light source of this sensor unit Optical fiber voltage measuring device including a measuring unit for converting and outputting and displaying a voltage signal and an optical fiber cable for transmitting a light beam and an optical signal between the measuring unit and the sensor unit, two optical fibers having the same phase Based on the voltage signal from each optical fiber voltage measuring device that belongs to the three-phase bridge connection, the resistance component current contained in the leakage current causes the deterioration of the bridge arrester. Those having a deterioration detector for displaying detects the current increment signal corresponding to the pressure component.

Further, it corresponds to each arm of a six-phase bridge connection rectifier circuit configured by connecting two three-phase bridge connections in series and connecting to two secondary windings of different phases of the transformer for converter. Detecting the voltage signal corresponding to the leakage current of the AK lightning arrester in the AC / A lightning arrester in which the AK lightning arrester is connected in parallel to the thyristor valve and the zinc oxide type lightning arrester is used for the AK lightning arrester. Resistance detector,
A sensor unit that converts this voltage signal into an optical signal by utilizing the electro-optical effect, a measuring unit that generates a light beam that serves as a light source of the sensor unit, converts the optical signal, and outputs the voltage signal to display. An optical fiber voltage measuring device composed of an optical fiber cable for transmitting a light beam and an optical signal between the measuring part and the sensor part, and voltage signals from the optical fiber voltage measuring devices belonging to two arms having different phases are of the same phase. Degradation that detects and displays the current increment signal corresponding to the increment due to the deterioration of the AK lightning arrester by the phase shifter for making each in-phase voltage signal and the resistance current included in the leakage current based on the two in-phase voltage signals Equipped with a detector.

Then, each of the three-phase bridge connections of the six-phase bridge connection rectifier circuit is configured by connecting two three-phase bridge connections in series and connecting to two secondary windings having different phases of the converter transformer. In the surge arrester for AC / DC converters, in which a bridge arrester is connected in parallel to the DC side terminal of the, and a zinc oxide type arrester is used in this bridge arrester, a resistance detector that detects the voltage signal corresponding to the leakage current of the bridge arrester, this voltage signal A sensor unit that converts the light signal into an optical signal by utilizing the electro-optical effect, a measuring unit that generates a light beam that serves as a light source of the sensor unit, converts the optical signal, and outputs a voltage signal for display, and the measuring unit. An optical fiber voltage measuring instrument consisting of an optical fiber cable for transmitting a light beam and an optical signal between the sensor parts, and voltage signals from the respective optical fiber voltage measuring instruments in the same phase. Comprising phase phaser into a voltage signal, the two degradation detector for detecting display the current increment signal corresponding to the increase due to the deterioration of the bridge arrester with resistor-current included in the basis of leakage current in phase voltage signal.

[0010]

According to the present invention, the deterioration detector has a resistance component current contained in the leakage current according to the deterioration of the AK lightning arrester based on the voltage signals from the optical fiber voltage measuring devices belonging to the two arms having the same phase. The current increment signal corresponding to the increasing amount is detected and displayed.

Further, according to the present invention, the deterioration detector deteriorates the bridge surge arrester due to the resistance component current contained in the leakage current based on the voltage signals from the respective optical fiber voltage measuring devices belonging to the two three-phase bridge connections having the same phase. The current increment signal corresponding to the increased amount is detected and displayed.

Further, according to the present invention, the voltage signals from the optical fiber voltage measuring devices belonging to the two arms having different phases are converted into in-phase voltage signals of the same phase by the phase shifter.
Based on the two in-phase voltage signals, the deterioration detector detects and displays a current increment signal corresponding to the increase in the resistance component current contained in the leakage current due to the deterioration of the AK lightning arrester.

According to the present invention, the voltage signals from the optical fiber voltage measuring devices belonging to the two three-phase bridge connections having different phases are converted into in-phase voltage signals of the same phase by the phase shifter, and the deterioration detector is Based on the two in-phase voltage signals, the resistance increment current contained in the leakage current increases with the deterioration of the bridge arrester, and the current increment signal corresponding to the increment is detected and displayed.

[0014]

【Example】

Example 1. FIG. 1 is a circuit diagram showing the configuration of an inverse converter station for direct current power transmission using a six-phase bridge connection rectifier circuit, which is the object of Embodiments 1 and 2 of the present invention. FIG. 2 is a circuit diagram showing a deterioration detection device for the U1 phase and U3 phase AK lightning arrester in FIG. In FIG. 1, 20 is a transformer for a primary star, secondary star, and a triangular connection, and 41 to 44 are thyristor valves, which are two transformers for connecting three three-phase bridges in series. It corresponds to each arm of a 6-phase bridge connection rectifier circuit in which 2 units of 1-unit 6-phase bridge connection configured by connecting to 2 secondary windings with 20 different phases are connected in series.
The phases of each arm are as shown. Reference numerals 51 to 54 are AK lightning arresters connected in parallel to the thyristor valves 41 to 44 of the respective phases, which are zinc oxide type arresters. All of 61 to 64 are bridge arresters connected in parallel to the DC side terminals of each three-phase bridge connection, using a zinc oxide type arrester. 70a, 70
b is a thyristor valve 41-44, AK arrester 51-54,
High-voltage side and low-voltage side DC lines connecting the reverse converter consisting of bridge arresters 61-64, etc., 80 smoothing the pulsating DC current, preventing current interruption in the case of light load, in case of DC system accident This is a DC reactor that is provided to suppress the current increase rate. Next, in FIG. 2, 41, 43, 51, 53 are explained in FIG. 111 and 131 are lightning arrester between AK 5
A resistance detector connected in series with 1 and 53 to detect the voltage signal corresponding to the leakage current, 112 and 132 are voltage signals detected by the resistance detectors 111 and 131, respectively, and converted into an optical signal by utilizing the electro-optic effect. The sensor units 113, 133 of the optical fiber voltage measuring device to be converted generate light beams which serve as the light sources of the sensor units 112, 132, respectively, and the sensor units 112, 132
The optical fiber voltage measuring device for converting and converting the optical signal converted in step 1 to output and displaying the voltage signal, 113a and 133a are voltmeters of measuring parts 113 and 133 for displaying the voltage signal, respectively.
Reference numerals 9 and 139 each constitute an optical fiber voltage measuring device with an optical fiber cable for transmitting a light beam and an optical signal between the sensor unit 112 and the measuring unit 113 and between the sensor unit 132 and the measuring unit 133, respectively. 114 and 134 are gaps that limit the overvoltage applied to the resistance detectors 111 and 131 due to surge currents when the AK lightning arresters 51 and 53 operate, respectively, and 151 is the output of the measuring units 113 and 133 of the optical fiber voltage measuring instrument. The resistance component current contained in the leakage current is based on the voltage signal
Deterioration detector that detects and displays the current increment signal corresponding to the increased amount that increases with deterioration of the deterioration detector 151, 151a and 151b are variable resistors of the deterioration detector 151, and 151c and 151d are both deterioration detector 151. A fixed resistor, 151e, is a voltmeter for the degradation detector 151 that indicates the magnitude and direction of the current increment signal.

The function of the first embodiment will be described below.
The AC-DC conversion is performed by controlling the control angles of the thyristor valves 41 to 44 corresponding to the arms of the six-phase bridge connection rectifier circuit to be the same and adjusting the magnitude and direction of the current flow. Therefore, U1-U3, V1-V3, W1-W
3, X1-X3, Y1-Y3, Z1-Z3, U2-U
4, V2-V4, W2-W4, X2-X4, Y2-Y
4, Z2-Z4 arms have the same phase and the same control angle. A U-K arrester connected in parallel to U1-U3 phase thyristor valves 51, 53 shown as an example in FIG.
As for 41 and 43, the arrester 51 between AK and 51,
The voltage in the reverse direction of the thyristor valves 41 and 43 and the blocking voltage in the forward direction by the phase control are applied to 53, respectively, and a leakage current is generated. This leak current is detected as each voltage signal by the resistance detectors 111 and 131, and the sensor unit 11 of the optical fiber voltage measuring device is detected.
2 and 132 convert to optical signals by using the electro-optic effect.
This is to convert the light beam of the light source into the intensity of the light by utilizing the phenomenon that the phase difference of the light changes according to the voltage when the light passes through the electro-optical element. Optical fiber cable 119
, 139. The optical signals converted by the sensor units 112 and 132 are transmitted by the optical fiber cables 119 and 139, and converted into the respective voltage signals again by the measuring units 113 and 133 to be converted into the voltmeter 113.
a and 133a and output to the deterioration detector 151. The deterioration detector 151 is a variable resistor 151a, 151b, a fixed resistor
It consists of 151c and 151d and voltmeter 151e, and initially has a variable resistance.
151a, is set resistance value of 151b r _1, r ₂ and the fixed resistor 151c, the resistance value R _1, R ₂ of 151d such that _{r 1 = r 2, R 1} = R 2. Since the thyristor valves 41 and 43 have the same phase, control angle, and overlapping angle, the lightning arresters 51 and 53 between AK
The leakage current waveforms are the same, so the voltmeter 151e
The indicated value of is zero. Further, when there is a difference in the state of the electric paths of the AK lightning arresters 51 and 53 and the indicated value of the voltmeter 151e fluctuates slightly, the variable resistors 151a and 151b are adjusted so that the indicated value becomes zero. deep. Leakage current increases after a long period of time after charging the A-K lightning arresters 51 and 53.
It is considered that the probability that both -K lightning arresters 51 and 53 deteriorate simultaneously is extremely low. Therefore, if one of the A-K lightning arresters 51 begins to deteriorate, the capacity current of the leakage current does not change, and only the resistance current increases. Due to this increase in the resistance current, the potential at point P ₁ of the deterioration detector 151 becomes P
The potential becomes higher than _{2 and} the voltmeter 151e indicates the potential difference and direction. The potential difference indicated by the voltmeter 151e and its direction are the current increment signal corresponding to the increase in the resistance current, and the deterioration of the AK arrester 51 can be known. Further, when the AK lightning arresters 51 and 53 are simultaneously deteriorated to the same extent, the measuring unit 113 of the optical fiber voltage measuring device,
You can see this by looking at the voltmeters 113a and 133a in 133. By the way, the waveform of the voltage applied to the A-K lightning arresters 51, 53 changes variously depending on the control angle of the thyristor valves 41, 43, the overlapping angle of commutation, and the direct current, and the leakage current also changes accordingly. According to the first embodiment, the resistance component current of the leakage current is AK based on the voltage signal corresponding to the leakage current of the AK arresters 51, 53 of the arms having the same phase and the same control angle.
The current increment signal corresponding to the increase that accompanies the deterioration of the lightning arresters 51, 53 is detected, and the deterioration is detected by this current increment signal. Therefore, the waveform of the voltage applied to the AK lightning arresters 51, 53 is changed. Irrespectively, it is possible to detect deterioration with high accuracy, and it is possible to constantly monitor and detect deterioration while operating the conversion station. Further, since the measuring unit 113 of the optical fiber voltage measuring device and the deterioration detector 151 are placed on the ground instead of at a high place and the indication values of the voltmeters 113a, 133a, 151e can be directly observed, it is extremely convenient without using binoculars. is there.
In the first embodiment, the AK lightning arresters 51, 53 connected in parallel to the U1-U3 thyristor valves 41, 43 have been described, but V1-V3, W1-W3, X1-X3.
Y1-Y3, Z1-Z3, U2-U4, V2-V4, W
The same applies to the AK lightning arresters 51-54 connected in parallel to the thyristor valves 41-44 of the respective phases 2-W4, X2-X4, Y2-Y4, Z2-Z4.

Example 2. FIG. 3 is a circuit diagram showing a deterioration detecting device for the bridge arresters 61 and 63 in FIG. 1, which is Embodiment 2 of the present invention. Since the control angles of the thyristor valves 41 to 44 corresponding to the arms of the six-phase bridge connection rectifier circuit are all controlled to be the same, a bridge arrester is used.
The DC voltages applied to 61, 63 and bridge arresters 62, 64 have the same pulsation phase and the same control angle. Bridge arrester
61 and 63 share about 1/4 of the DC voltage applied to the DC lines 70a and 70b, respectively, and generate leakage current. The leak currents are detected as voltage signals by the resistance detectors 211 and 231, and converted into optical signals by utilizing the electro-optical effect at the sensor units 112 and 132 of the optical fiber voltage measuring device. The optical signals are transmitted by the optical fiber cables 119 and 139, respectively, and the measuring unit 113 and
At 133, it is converted into each voltage signal again and displayed on the voltmeters 113a and 133a and is output to the deterioration detector 151. In the deterioration detector 151, the resistance values r ₁ and r of the variable resistors 151a and 151b are initially set.
₂ and the resistance values R ₁ and R ₂ of the fixed resistors 151c and 151d as r ₁ = r
₂ , so that R ₁ = R ₂ , the voltmeter 151e
The indicated value of is zero. The leakage current increases after a long time has passed since the bridge arresters 61, 63 were charged with electricity.
If one of the bridge arresters 61 starts to deteriorate, the resistance component of the leakage current increases. Due to this increase in the resistance current, the potential at the P ₁ point of the deterioration detector 151 becomes P ₂
The potential becomes higher than the potential of the point, and the voltmeter 151e indicates the potential difference and the direction. The potential difference indicated by the voltmeter 151e and its direction are current increment signals corresponding to the increment of the resistance current, and the deterioration of the bridge arrester 61 can be known. If the bridge arresters 61 and 63 are deteriorated to the same degree at the same time, the measuring unit 113 of the optical fiber voltage measuring device,
You can see this by looking at the voltmeters 113a and 133a in 133. The voltage waveform applied to the bridge arresters 61 and 63 is the thyristor valve 4
The control angle of 1, 43, the overlapping angle of commutation, and the direct current change, and the leakage current changes accordingly.
According to the bridge arrester 61, which has the same phase and the same control angle,
Based on the voltage signal corresponding to the leakage current of 63, the current increment signal corresponding to the increase in the resistance current of the leakage current is detected, and the deterioration is detected by this current increment signal, so
Regardless of the waveform of the voltage applied to the bridge arresters 61 and 63,
It is possible to detect deterioration with a high degree of accuracy, and it is possible to constantly monitor and detect deterioration while operating the conversion station. Further, as in the first embodiment, the indication values of the voltmeters 113a, 133a, 151e can be read without using binoculars. Although the bridge arresters 61 and 63 have been described in the second embodiment, the same applies to the bridge arresters 62 and 64.

Embodiment 3. FIG. 4 is a circuit diagram showing a configuration of an inverse converter station for DC power transmission in which the six-phase bridge connection rectifier circuit is composed of half of the converters and transformers for converters in FIG. 1, and FIG. 5 shows U1 phases having different phases in FIG. It is an electric circuit block diagram which shows the deterioration detection apparatus of the U2-phase AK lightning arrester. There is no arm of the six-phase bridge connection rectifier circuit shown in FIG. 4 that has the same phase relationship. Therefore, the AK lightning arresters 51, 52 connected in parallel to the U1-U2 phase thyristor valves 41, 42 shown as an example in FIG. 2 will be described. The leak currents of the A-K lightning arresters 51, 52 are detected by the resistance detectors 111, 121 as respective voltage signals, and the sensor unit 11 of the optical fiber voltage measuring device is detected.
2 and 122 convert to an optical signal using the electro-optic effect.
This optical signal is transmitted by the optical fiber cables 119 and 129,
The measuring units 113 and 123 convert the voltage signals again and convert them into voltmeters.
Display with 113a and 123a. Since the voltage signals output from the measuring unit 113 and the measuring unit 123 have different phases, the voltage signal from the measuring unit 113 is input to the phase shifter 181 to adjust the phase, and the voltage signal of the same phase as the voltage signal from the measuring unit 123 is input. Use in-phase voltage signals. After that, the process of detecting the current increment signal corresponding to the increase of the resistance component current of the leakage current in the deterioration detector 151 is the same as that of the first embodiment, and the description thereof will be omitted. Any two phase AK lightning arresters 51, 52
The same applies to.

Example 4. 6 is a circuit diagram showing a deterioration detecting device for the bridge arresters 61 and 62 in FIG. 4, which is Embodiment 4 of the present invention. Each bridge arrester 61,
The pulsating phase of the DC voltage applied to 62 is different. The leak current of the bridge arresters 61 and 62 is detected as voltage signals by the resistance detectors 211 and 221 and the sensor part of the optical fiber voltage measuring device is detected.
At 112 and 122, it is converted into an optical signal by utilizing the electro-optic effect. The respective optical signals are transmitted by the optical fiber cables 119 and 129, converted again into the respective voltage signals by the measuring units 113 and 123, and displayed by the voltmeters 113a and 123a. Measuring unit 113 and measuring unit 123
Since each voltage signal output from the
The phase signal of the voltage signal from 3 is adjusted by the phase shifter 181 to make the same phase voltage signal as the voltage signal from the measuring unit 123. After that, the process of detecting the current increment signal corresponding to the increase of the resistance current of the leakage current in the deterioration detector 151 is the same as that of the second embodiment, and therefore the description thereof is omitted.

[0019]

As described above, according to the present invention, 2
One three-phase bridge connection is connected in series and is connected to two secondary windings with different phases of a transformer for a converter.
A AK lightning arrester is connected in parallel to a thyristor valve corresponding to each arm of a six-phase bridge connection rectifier circuit in which two units of the six-phase bridge connection are connected in series, and zinc oxide is connected to this AK lightning arrester. In a surge arrester for an AC / DC converter using a surge arrester, a resistance detector that detects a voltage signal corresponding to the leakage current of the AK lightning arrester, a sensor unit that converts this voltage signal into an optical signal by utilizing the electro-optical effect, A measuring unit that generates a light beam that serves as a light source for this sensor unit, converts the optical signal, and outputs a voltage signal to display, and an optical fiber cable that transmits the light beam and the optical signal between the measuring unit and the sensor unit. Based on the voltage signals from the optical fiber voltage measuring devices consisting of and the optical fiber voltage measuring devices belonging to the two arms having the same phase, the resistance component current included in the leakage current is A Since the deterioration detector that detects and displays the current increment signal corresponding to the increase due to the deterioration of the lightning arrester between K is equipped, the deterioration can be detected with high accuracy and the operation of the conversion station is constantly monitored without stopping. However, deterioration can be detected, and it is not necessary to use binoculars to detect deterioration.

Further, a bridge arrester is connected in parallel to the DC terminal of each three-phase bridge connection of the same six-phase bridge connection rectification circuit as described above, and in the arrester for AC / DC converter using a zinc oxide type arrester for this bridge arrester, A resistance detector that detects the voltage signal corresponding to the leakage current of the lightning arrester, a sensor unit that converts this voltage signal into an optical signal by using the electro-optical effect, and a light beam that serves as the light source of this sensor unit Optical fiber voltage measuring device including a measuring unit for converting and outputting and displaying a voltage signal and an optical fiber cable for transmitting a light beam and an optical signal between the measuring unit and the sensor unit, two optical fibers having the same phase Based on the voltage signal from each optical fiber voltage measuring device that belongs to the three-phase bridge connection, the resistance component current contained in the leakage current causes the deterioration of the bridge arrester. Since it is equipped with a deterioration detector that detects and displays the current increment signal corresponding to the addition, it is possible to detect deterioration with high accuracy and at the same time monitor the deterioration without stopping the operation of the conversion station. Further, it is not necessary to use binoculars for detecting deterioration.

Further, it corresponds to each arm of a six-phase bridge connection rectification circuit constructed by connecting two three-phase bridge connections in series and connecting to two secondary windings having different phases of the converter transformer. Detecting the voltage signal corresponding to the leakage current of the AK lightning arrester in the AC / A lightning arrester in which the AK lightning arrester is connected in parallel to the thyristor valve and the zinc oxide type lightning arrester is used for the AK lightning arrester. Resistance detector,
A sensor unit that converts this voltage signal into an optical signal by utilizing the electro-optical effect, a measuring unit that generates a light beam that serves as a light source of the sensor unit, converts the optical signal, and outputs the voltage signal to display. An optical fiber voltage measuring device composed of an optical fiber cable for transmitting a light beam and an optical signal between the measuring part and the sensor part, and voltage signals from the optical fiber voltage measuring devices belonging to two arms having different phases are of the same phase. Degradation that detects and displays the current increment signal corresponding to the increment due to the deterioration of the AK lightning arrester by the phase shifter for making each in-phase voltage signal and the resistance current included in the leakage current based on the two in-phase voltage signals Since it is equipped with a detector, it is possible to detect deterioration with high accuracy and at the same time to monitor deterioration without stopping the operation of the conversion station, and to use binoculars to detect deterioration. There is no. In addition, 2 with different phases
Deterioration of the three-phase AK lightning arrester can be detected.

Each of the three-phase bridge connections of the six-phase bridge connection rectifier circuit is configured by connecting two three-phase bridge connections in series and connecting to two secondary windings of different phases of the converter transformer. In the surge arrester for AC / DC converters, in which a bridge arrester is connected in parallel to the DC side terminal of the, and a zinc oxide type arrester is used in this bridge arrester, a resistance detector that detects the voltage signal corresponding to the leakage current of the bridge arrester, this voltage signal A sensor unit that converts the light signal into an optical signal by utilizing the electro-optical effect, a measuring unit that generates a light beam that serves as a light source of the sensor unit, converts the optical signal, and outputs a voltage signal for display, and the measuring unit. An optical fiber voltage measuring instrument consisting of an optical fiber cable for transmitting a light beam and an optical signal between the sensor parts, and voltage signals from the respective optical fiber voltage measuring instruments in the same phase. Phase detector for phase voltage signal, Degradation detector for detecting and displaying current increment signal corresponding to increase due to deterioration of bridge arrester by resistance component current included in leakage current based on two in-phase voltage signals Therefore, the deterioration can be detected with high accuracy, and the deterioration can be detected constantly while monitoring without stopping the operation of the conversion station, and it is not necessary to use the binoculars to detect the deterioration.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an inverse converter station for DC power transmission.

FIG. 2 is a circuit diagram showing a deterioration detecting device for the two AK lightning arresters of FIG.

FIG. 3 is a circuit diagram showing a deterioration detecting device for the bridge arrester of FIG.

FIG. 4 is a circuit diagram showing a configuration of an inverse converter station for DC power transmission.

5 is a circuit diagram showing a deterioration detecting device for the two AK lightning arresters of FIG.

6 is a circuit diagram showing a deterioration detection device for the bridge arrester of FIG.

[Fig. 7] Fig. 7 is a single-line electric circuit diagram showing a circuit structure of an inverse converter station for DC power transmission.

FIG. 8 is a circuit diagram showing a conventional deterioration detecting device for an AK lightning arrester.

[Explanation of symbols]

20 Transformer transformer, 41-44 Thyristor valve, 51-
54 AK Lightning Arrester, 61 ~ 64 Bridge Arrester, 111
Resistance detector, 112 sensor section, 113 measuring section, 113a voltmeter, 119 optical fiber cable, 121 resistance detector,
122 sensor part, 123 measuring part, 123a voltmeter, 129 optical fiber cable, 131 resistance detector, 132 sensor part, 133 measuring part, 133a voltmeter, 139 optical fiber cable, 151 deterioration detector, 151a, 151b variable resistance, 15
1c, 151d Fixed resistance, 151e Voltmeter, 181 Phaser, 21
1 resistance detector, 221 resistance detector, 231 resistance detector

Claims (4)

[Claims] 1. One unit of a six-phase bridge connection, which is configured by connecting two three-phase bridge connections in series and connected to two secondary windings of different phases of a transformer for converter, in series. A surge arrester for an AC / DC converter, in which an AK lightning arrester is connected in parallel to a thyristor valve corresponding to each arm of a six-phase bridge connection rectifier circuit, and a zinc oxide type lightning arrester is used for the AK lightning arrester. The AK
A resistance detector that detects a voltage signal corresponding to the leakage current of the lightning arrester, a sensor unit that converts the voltage signal into an optical signal by utilizing the electro-optical effect, and a light beam that serves as a light source of the sensor unit A measuring unit for converting an optical signal to output and displaying the voltage signal, and an optical fiber voltage measuring device comprising an optical fiber cable for transmitting the light beam and the optical signal between the measuring unit and the sensor unit, Based on the voltage signal from each of the optical fiber voltage measuring devices belonging to the two arms having the same phase, the resistance component current included in the leakage current corresponds to the increase due to the deterioration of the AK lightning arrester. A deterioration detector for a surge arrester for an AC / DC converter, comprising a deterioration detector for detecting and displaying a current increment signal. 2. One unit of six-phase bridge connection, which is formed by connecting two three-phase bridge connections in series and connected to two secondary windings having different phases of a transformer for converter, in series of two units. A surge arrester for a direct-current converter, in which a bridge arrester is connected in parallel to the DC side terminals of each of the three-phase bridge connections of a six-phase bridge connection rectifier circuit, and a zinc oxide type arrester is used for the bridge arrester, wherein the bridge arrester is used. Resistance detector for detecting a voltage signal corresponding to the leakage current of the sensor, a sensor unit for converting the voltage signal into an optical signal by utilizing the electro-optical effect, and a light beam which serves as a light source of the sensor unit and the optical signal. From the measuring unit that converts the voltage signal to output and display the voltage signal, and the optical fiber cable that transmits the light beam and the optical signal between the measuring unit and the sensor unit. Optical fiber voltage measuring device, and based on the voltage signal from each of the optical fiber voltage measuring devices belonging to the two three-phase bridge connections having the same phase, deterioration of the bridge arrester due to a resistance component current included in the leakage current A deterioration detector for a surge arrester for an AC / DC converter, comprising a deterioration detector for detecting and displaying a current increment signal corresponding to the increase due to. 3. Corresponding to each arm of a six-phase bridge connection rectifier circuit configured by connecting two three-phase bridge connections in series and connecting to two secondary windings having different phases of a transformer for a converter. Detecting a voltage signal corresponding to the leakage current of the A-K lightning arrester in an AC / A lightning arrester in which a AK lightning arrester is connected in parallel to a thyristor valve and a zinc oxide type lightning arrester is used for the AK lightning arrester. Resistance detector,
A sensor unit that converts the voltage signal into an optical signal by utilizing an electro-optical effect, and a measuring unit that generates a light beam that serves as a light source of the sensor unit and converts the optical signal to output the voltage signal for display. , An optical fiber voltage measuring instrument comprising an optical fiber cable for transmitting the light beam and the optical signal between the measuring section and the sensor section, from each of the optical fiber voltage measuring instruments belonging to the two arms having different phases Of a phase shifter for converting the voltage signals into in-phase voltage signals of the same phase, and a resistance component current included in the leakage current based on the two in-phase voltage signals, and an increment due to deterioration of the AK arrester. Is provided with a deterioration detector for detecting and displaying a current increment signal corresponding to, and a deterioration detecting device for a surge arrester for an AC / DC converter. 4. A three-phase bridge of a six-phase bridge connection rectifier circuit, which is configured by connecting two three-phase bridge connections in series and connecting to two secondary windings having different phases of a transformer for a converter. A bridge arrester is connected in parallel to the DC side terminal of the connection, in an AC / DC converter arrester using a zinc oxide type arrester for the bridge arrester, a resistance detector that detects a voltage signal corresponding to the leakage current of the bridge arrester,
A sensor unit that converts the voltage signal into an optical signal by utilizing an electro-optical effect, and a measuring unit that generates a light beam that serves as a light source of the sensor unit and converts the optical signal to output the voltage signal for display. , An optical fiber voltage measuring device comprising an optical fiber cable for transmitting the light beam and the optical signal between the measuring part and the sensor part, each of the voltage signals from the respective optical fiber voltage measuring devices in the same phase Degradation detection for detecting and displaying a current increment signal corresponding to an increase due to degradation of the bridge arrester based on two in-phase voltage signals and a resistance component current included in the leakage current based on the two in-phase voltage signals A device for detecting deterioration of a lightning arrester for an AC / DC converter, which is provided with a device.