Fault positioning method and device in operation state of direct-current multi-column parallel lightning arrester

Abstract

The invention discloses a fault positioning method in a running state of a direct-current multi-column parallel lightning arrester. The method comprises the following steps: collecting direct-current leakage current of each column lightning arrester through a direct-current leakage current sensor; collecting the DC line voltage of a line voltage divider connected in parallel with the lightning arrester in the DC field of the converter station through a line voltage sensor; action current of the lightning arrester on each column is collected through an action current sensor; judging the state of the insulation resistance of each column lightning arrester by using the insulation resistance under the operating voltage of each column lightning arrester and the factory insulation resistance of the corresponding column lightning arrester; and judging the state of the dynamic resistance of each column lightning arrester by using the action resistance value of each column lightning arrester, the average value of the action resistance of the lightning arrester and the maximum change resistance value of each column lightning arrester. According to the invention, the deterioration and fault of the lightning arrester group can be accurately judged, and the fault lightning arrester is prepared to be positioned.

Description

Technical Field

[0001] The present invention relates to the technical field of arrester fault detection, and in particular to a method and a device for locating faults of a DC multi-column parallel arrester in operation. Background Art

[0002] On the metal loop of the DC field of the UHV converter station, multi-column parallel arresters are usually installed. They have the characteristics of current sharing and strong energy absorption, and can effectively absorb the continuous current shock caused by the operating overvoltage of the metal loop. When the performance of a column arrester in the DC multi-column parallel arrester group deteriorates or fails, the overall performance of the arrester group will be affected; the existing detection method is to detect the single-column arrester during power outage; the distance between the two branches of the DC parallel arrester group is only 5 to 30 cm, and it is very difficult to dismantle and install. At the same time, the overall test of the arrester group is significantly affected by the capacity of the test equipment and spatial coupling; the existing online detection method of the DC multi-column parallel arrester group is limited, and it is impossible to grasp the operating status of each column arrester in the arrester group in real time. At present, it is very difficult to locate the fault of the arrester group. Summary of the invention

[0003] The purpose of the present invention is to provide a method and device for locating faults in a DC multi-column parallel arrester under operation. The present invention can accurately judge the degradation and faults of the arrester group and is ready to locate the faulty arrester.

[0004] To achieve this purpose, the present invention provides a method for locating a fault in a DC multi-column parallel arrester in operation, which comprises the following steps:

[0005] The DC leakage current of each column arrester is collected by a DC leakage current sensor;

[0006] The DC line voltage of the line voltage divider connected in parallel with the lightning arrester in the DC field of the converter station is collected by a line voltage sensor;

[0007] The action current of each column arrester is collected through the action current sensor;

[0008] The insulation resistance of each column lightning arrester under the operating voltage is calculated by the DC line voltage of the line voltage divider and the DC leakage current of each column lightning arrester. The insulation resistance of each column lightning arrester under the operating voltage and the factory insulation resistance of the corresponding column lightning arrester are used to determine the insulation resistance status of each column lightning arrester.

[0009] The action resistance value of the corresponding column lightning arrester is calculated by the action current of each column lightning arrester; the average action resistance of the lightning arrester is calculated according to the action resistance value of each column lightning arrester; the residual voltage at the peak point of the action current of each column lightning arrester is used to calculate the residual pressure resistance under the action current of each column lightning arrester; the state of the dynamic resistance of each column lightning arrester is determined by the action resistance value of each column lightning arrester, the average action resistance of the lightning arrester, the residual pressure resistance under the action current of each column lightning arrester and the maximum change resistance value of each column lightning arrester.

[0010] Optionally, the DC leakage current sensor is connected in parallel to both ends of the action current counter of each column lightning arrester, and the low impedance input circuit of the DC leakage current sensor is in a normally open state. When the preset collection time is reached, the DC leakage current sensor collects the DC leakage current of each column lightning arrester through the low impedance input circuit.

[0011] Optionally, the DC line voltage collected by the line voltage sensor and the action current of each column lightning arrester collected by the action current sensor are continuously pre-sampled and triggered for sampling through a high-speed synchronous acquisition module, and the pre-sampled data are placed in a first-in-first-out queue of a fixed length. When it is detected that the action current signal of any column lightning arrester meets the preset trigger condition, the high-speed synchronous acquisition module is started to collect a continuous waveform of the action current signal of a preset duration; the high-speed synchronous acquisition module sorts the continuous waveform of the action current signal with the DC line voltage collected by the line voltage sensor and the action current of each column lightning arrester collected by the action current sensor in chronological order of sampling time to form an action waveform.

[0012] Optionally, the specific method for judging the insulation resistance status of each column arrester is as follows:

[0013] When R 运行 >R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is ≈ the preset slope k, the insulation state of the column arrester is normal, where R 运行 is the insulation resistance of a column arrester under the operating voltage, R 参考 The factory insulation resistance of the corresponding column arrester;

[0014] When R 运行 >R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is less than the preset slope k, the insulation resistance of the column arrester is degraded;

[0015] When R 运行 <R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is less than the preset slope k, there is a fault in the insulation resistance of the column lightning arrester.

[0016] Optionally, the specific method for judging the dynamic resistance state of each column arrester by using the action resistance value of each column arrester, the average action resistance value of the arrester, the residual voltage resistance under the action current of each column arrester and the maximum change resistance value of each column arrester is:

[0017] When | R 动作 -R 平均 |<ΔR, and |R 动作 -R 残压 |<ΔR, the dynamic resistance state of the column arrester is normal, where R 动作 is the operating resistance value of a column arrester, R 平均 is the average value of the arrester action resistance, R 残压 is the residual voltage resistance of the column arrester under the operating current, ΔR is the maximum variable resistance value of the column arrester;

[0018] When | R 动作 -R 平均 |>ΔR, and |R 动作 -R 残压 |<ΔR, the dynamic resistance of the column arrester is degraded;

[0019] When | R 动作 -R 平均 |>ΔR, and |R 动作 -R 残压 |>ΔR, the column arrester is faulty.

[0020] Optionally, the specific method for calculating the average value of the arrester action resistance according to the action resistance value of each column arrester is:

[0021] The calculated action resistance values ​​of all arresters are sorted from large to small, the largest and smallest resistance values ​​are removed, and the average of the intermediate action resistance values ​​is calculated to obtain the average action resistance value of the arrester.

[0022] The present invention is a fault locating device for a DC multi-column parallel arrester in operation, comprising:

[0023] The DC leakage current sensor is used to collect the DC leakage current of each column arrester;

[0024] The line voltage sensor is used to collect the DC line voltage of the line voltage divider connected in parallel with the arrester in the DC field of the converter station;

[0025] The operating current sensor is used to collect the operating current of each column arrester;

[0026] The fault location host is used to calculate the insulation resistance of each column lightning arrester under the operating voltage through the DC line voltage of the line voltage divider and the DC leakage current of each column lightning arrester, and to determine the state of the insulation resistance of each column lightning arrester by using the insulation resistance of each column lightning arrester under the operating voltage and the factory insulation resistance of the corresponding column lightning arrester;

[0027] The fault locating host is used to calculate the action resistance value of the corresponding column lightning arrester through the action current of each column lightning arrester; calculate the average action resistance of the lightning arrester according to the action resistance value of each column lightning arrester; use the residual voltage at the peak point of the action current of each column lightning arrester to calculate the residual pressure resistance under the action current of each column lightning arrester; use the action resistance value of each column lightning arrester, the average action resistance of the lightning arrester, the residual pressure resistance under the action current of each column lightning arrester and the maximum change resistance value of each column lightning arrester to determine the state of the dynamic resistance of each column lightning arrester.

[0028] The device of the present invention regularly collects the insulation resistance of each column of the DC multi-column parallel lightning arrester in the operating state, and dynamically captures the voltage and current waveforms of each column of the DC lightning arrester under the action of operating overvoltage, calculates the dynamic resistance change curve, comprehensively analyzes the monitoring data and the factory parameters of the lightning arrester, and realizes intelligent judgment of the degradation and failure of the lightning arrester group.

[0029] The working principle of the present invention is:

[0030] The valve plate current of the metal zinc oxide arrester has a nonlinear relationship with the voltage. The resistance value of the valve plate is related to the current passing through. Under the operating voltage, the valve plate is equivalent to a very high resistor. A very small current flows through the valve plate, and its insulation resistance is basically linear. When the operating current flows through the valve plate, it is equivalent to a very small resistor to maintain an appropriate residual pressure, and its dynamic resistance is also basically linear. The device calculates the insulation resistance of the arrester in the steady state, collects the operating current flowing through the arrester under the operating overvoltage, and fully senses the operating status of the arrester.

[0031] Beneficial effects of the present invention:

[0032] 1. The present invention monitors the insulation resistance of the DC multi-column parallel arrester in operation, analyzes the change trend of the arrester insulation resistance history curve, and senses the arrester insulation state online in combination with the arrester DC test parameters.

[0033] 2. The present invention dynamically collects the resistance change of each column of the parallel lightning arrester group during the operating current, combines the residual voltage data of the lightning arrester under the factory operating current, and monitors the dynamic resistance change of each column lightning arrester.

[0034] 3. The present invention integrates the static insulation and dynamic resistance monitoring of the arrester to achieve a comprehensive evaluation of the status of the DC parallel arrester group; the device reduces the power outage inspection and operation and maintenance costs of the arrester and provides data support for the arrester status evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the present invention;

[0036] Figure 2 It is a flow chart for judging the insulation resistance state of each column arrester in the present invention;

[0037] Figure 3 This is a flow chart of high-speed synchronous acquisition in the present invention;

[0038] Figure 4 The figure is a flow chart for determining the dynamic resistance state of each column arrester in the present invention.

[0039] Among them, 1 is a DC leakage current sensor, 2 is a line voltage sensor, 3 is an action current sensor, 4 is a high-speed synchronous acquisition module, and 5 is a fault location host. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0041] Example 1

[0042] A method for locating faults in a DC multi-column parallel arrester in operation, comprising the following steps:

[0043] The DC leakage current of each column arrester is collected by the DC leakage current sensor 1, and the DC leakage current is a DC microampere level current;

[0044] The DC line voltage (DC low voltage signal) of the line voltage divider connected in parallel with the arrester in the DC field of the converter station is collected by the line voltage sensor 2;

[0045] The action current of each column arrester is collected through the action current sensor 3;

[0046] The insulation resistance of each column lightning arrester under the operating voltage is calculated by the DC line voltage of the line voltage divider and the DC leakage current of each column lightning arrester. The insulation resistance of each column lightning arrester under the operating voltage and the factory insulation resistance of the corresponding column lightning arrester are used to determine the insulation resistance status of each column lightning arrester.

[0047] Calculate the action resistance value of the corresponding column lightning arrester through the action current of each column lightning arrester; calculate the average action resistance of the lightning arrester according to the action resistance value of each column lightning arrester; use the residual voltage at the peak point of the action current of each column lightning arrester provided by the lightning arrester manufacturer or maintenance company to calculate the residual pressure resistance under the action current of each column lightning arrester; judge the state of the dynamic resistance of each column lightning arrester by the action resistance value of each column lightning arrester, the average action resistance of the lightning arrester, the residual pressure resistance under the action current of each column lightning arrester and the maximum change resistance value of each column lightning arrester.

[0048] According to the above steps, the fault of DC multi-column parallel lightning arrester can be quickly detected.

[0049] In the above technical solution, the lightning arresters of each column are connected in parallel to form a lightning arrester group (seven-column lightning arresters in this embodiment), and the line voltage divider is connected in parallel with the lightning arrester group.

[0050] In the above technical solution, the DC leakage current sensor 1 is connected to both ends of the action current counter of each column lightning arrester. The low impedance input circuit of the DC leakage current sensor 1 is in a normally open state. When the preset collection time is reached, the DC leakage current sensor 1 connects the low impedance input circuit through a relay controlled by the microcontroller of the DC leakage current sensor to collect the DC leakage current of each column lightning arrester. The low impedance input circuit is used to perform resistance sampling on the current signal and convert it into voltage. Its impedance is much smaller than the internal impedance of the lightning arrester counter, and most of the leakage current flows through the current signal sampling circuit. The above collection time is jointly determined by relevant standards or the FLASH capacity of the device. The default interval is 1 hour to start the collection once;

[0051] In the above technical solution, the DC leakage current sensor 1 is used to accurately measure the DC leakage current of the lightning arrester by utilizing the AC signal suppression and DC gain conditioning functions. The AC signal suppression solves the abnormal fluctuations in the measured value caused by the interference of the power frequency and high-order harmonic signals on the DC measurement; the DC gain conditioning automatically amplifies the microvolt voltage signal to the volt level, ensuring that the analog-to-digital circuit can distinguish microampere current changes.

[0052] In the above technical solution, the line voltage divider is configured at both ends of the DC line input and output in the DC field of the converter station. The line voltage sensor 2 is used to sample the voltage at both ends of the lightning arrester and the leakage current of the single-column lightning arrester to calculate the insulation resistance of the lightning arrester.

[0053] In the above technical solution, the coil of the action current sensor 3 is sleeved on the grounding down conductor under the arrester, and the action current signal is sampled by the Rogowski coil. When the DC line is closed or opened, due to the inductance and capacitance of the DC transmission line, an operation overvoltage will be generated on the line. This embodiment collects the dynamic resistance change of each column of the DC arrester when the operation overvoltage acts (the on-resistance of the arrester under the action of the action voltage).

[0054] In the above technical scheme, the DC line voltage collected by the line voltage sensor 2 and the action current of each column lightning arrester collected by the action current sensor 3 are continuously pre-sampled and triggered for sampling by the high-speed synchronous acquisition module 4 (in this embodiment, 7 action currents and 1 line voltage signal corresponding to 7 column lightning arresters), and the pre-sampled data are placed in a first-in-first-out queue (FIFO) of fixed length. When it is detected that the action current signal of any column lightning arrester meets the preset trigger condition (the set trigger threshold and the number of continuous trigger points), the high-speed synchronous acquisition module 4 is started to collect the continuous waveform of the action current signal with a duration of 70ms (the continuous waveform with a duration of 70ms is dynamically updated over time, and is always the waveform with a duration of the most recent 70ms); the high-speed synchronous acquisition module 4 sorts the continuous waveform of the action current signal with the DC line voltage collected by the line voltage sensor 2 and the action current of each column lightning arrester collected by the action current sensor 3 according to the sampling time, with a total of 80ms for each channel, to form an action waveform, such as Figure 3 As shown. This solution further stores a continuous signal waveform in FIFO for 10ms; when a current channel signal is detected to meet the trigger condition, the high-speed synchronous acquisition module is started to continuously acquire a signal waveform of 70ms; the device combines the pre-sampled data with the triggered sampled data to form an action waveform of 80ms continuous duration for group storage. Since the high-speed synchronous acquisition module 4 does not know when the line will have an overvoltage, the above-mentioned capture action current waveform is used to realize the device trigger control and latch the 80ms waveform.

[0055] In this embodiment, the insulation resistance of each column lightning arrester under the operating voltage is equivalent to the static resistance; and the trigger acquisition is to measure the dynamic resistance of the lightning arrester when it is turned on.

[0056] In the above technical solution, if Figure 2 The specific method for judging the insulation resistance status of each column arrester is as follows:

[0057] When R 运行 ≥R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is ≈ the preset slope k, the insulation state of the column arrester is normal, and the column state is indicated in green, where R 运行 is the insulation resistance of a column arrester under the operating voltage, R 参考 The factory insulation resistance of the corresponding column arrester;

[0058] When R 运行 ≥R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is less than the preset slope k, the insulation resistance of the column arrester is degraded, and the column status is indicated in yellow;

[0059] When R 运行 <R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is less than the preset slope k, the insulation resistance of the arrester of the column is faulty, and the column status is indicated in red. The above scheme can be used to judge the insulation status of each column of the arrester online and identify the arrester fault.

[0060] In this embodiment, the insulation resistance data monitored during the operation of the arrester for a period of time is continuously counted, and the change law of the insulation resistance of each column arrester is analyzed. Affected by the environment, the insulation resistance of each column arrester fluctuates with the time axis, and the historical curve tends to change linearly. When the preset slope k is 1, the insulation resistance R 运行 The curve that fluctuates with the time axis is a straight line parallel to the horizontal axis. When the slope k is 1, the arrester insulation has not deteriorated, and the historical curve tends to a horizontal straight line. The decrease in insulation resistance indicates that the arrester insulation has slowly deteriorated; when the insulation resistance decreases by an order of magnitude, it needs to be replaced.

[0061] In the above technical solution, if Figure 4 As shown, the specific method for judging the dynamic resistance state of each column arrester by using the action resistance value of each column arrester, the average action resistance value of the arrester, the residual voltage resistance under the action current of each column arrester and the maximum change resistance value of each column arrester is:

[0062] When | R 动作 -R 平均 |<ΔR, and |R 动作 -R 残压 |<ΔR, the dynamic resistance state of the column arrester is normal, and the column state is indicated in green, where R 动作 is the operating resistance value of a column arrester, R 平均 is the average value of the arrester action resistance, R 残压 is the residual voltage resistance under the action current of the column arrester, ΔR is the maximum variable resistance value of the column arrester, which is the factory detection parameter of the arrester;

[0063] When | R 动作 -R 平均 |>ΔR, and |R 动作 -R 残压 When |<ΔR, the arrester of the column is degraded, and the column status is indicated in yellow;

[0064] When | R 动作 -R 平均 |>ΔR, and |R 动作 -R 残压|>ΔR, the arrester of the column is faulty, and the column status is indicated in red. The dynamic resistance under the arrester action voltage is basically linear. If it is too large, it means that there is an open circuit inside the arrester; if it is too small, it means that there is a short circuit inside the arrester. It is known from experiments that the internal resistance of the arrester does not change much under overvoltage. The above scheme locates the arrester fault by analyzing the change of the dynamic resistance value of the arrester under overvoltage.

[0065] In the above technical solution, the specific method for calculating the average value of the arrester action resistance according to the action resistance value of each column arrester is:

[0066] The fault location host 5 reads the data packet from the high-speed synchronous acquisition module 4, retrieves the action current waveform by the comparison method, and finds all the peak points of the action current waveform; obtains the voltage value corresponding to the current peak point by referring to the sampling point serial number, calculates the resistance value of each column lightning arrester under the action current according to the peak point voltage and current value, and averages the dynamic resistance value of the column when there are multiple current peak points, sorts the calculated action resistance values ​​of all lightning arresters from large to small, removes the largest and smallest resistance values, and averages the intermediate action resistance values ​​to obtain the average action resistance value of the lightning arrester.

[0067] In the above technical scheme, the method for calculating the factory insulation resistance of the lightning arrester is: using the lightning arrester DC reference voltage U1mA and the leakage current corresponding to 0.75U1mA provided by the lightning arrester manufacturer or maintenance company as parameters, and using 0.75U1mA / leakage current to calculate the factory insulation resistance of each column lightning arrester.

[0068] Example 2

[0069] A fault locating device for a DC multi-column parallel arrester in operation, such as Figure 1 As shown, it includes:

[0070] The DC leakage current sensor 1 is used to collect the DC leakage current of each column arrester;

[0071] The line voltage sensor 2 is used to collect the DC line voltage of the line voltage divider connected in parallel with the arrester in the DC field of the converter station;

[0072] The operating current sensor 3 is used to collect the operating current of each column arrester;

[0073] The fault location host 5 is used to calculate the insulation resistance of each column lightning arrester under the operating voltage through the DC line voltage of the line voltage divider and the DC leakage current of each column lightning arrester, and to determine the state of the insulation resistance of each column lightning arrester by using the insulation resistance of each column lightning arrester under the operating voltage and the factory insulation resistance of the corresponding column lightning arrester;

[0074] The fault locating host 5 is used to calculate the action resistance value of the corresponding column lightning arrester through the action current of each column lightning arrester; calculate the average action resistance of the lightning arrester according to the action resistance value of each column lightning arrester; use the residual voltage at the peak point of the action current of each column lightning arrester to calculate the residual pressure resistance of each column lightning arrester under the action current; use the action resistance value of each column lightning arrester, the average action resistance of the lightning arrester, the residual pressure resistance of each column lightning arrester under the action current and the maximum change resistance value of each column lightning arrester to determine the state of the dynamic resistance of each column lightning arrester.

[0075] In embodiment 2, it also includes a high-speed synchronous acquisition module 4 for continuously pre-sampling and triggering sampling of the DC line voltage collected by the line voltage sensor 2 and the action current of each column lightning arrester collected by the action current sensor 3, and the pre-sampled data is placed in a first-in-first-out queue of a fixed length. When it is detected that the action current signal of any column lightning arrester meets the preset trigger condition, the high-speed synchronous acquisition module 4 is started to collect the continuous waveform of the action current signal of a preset time length; the high-speed synchronous acquisition module 4 sorts the continuous waveform of the action current signal with the DC line voltage collected by the line voltage sensor 2 and the action current of each column lightning arrester collected by the action current sensor 3 according to the sampling time to form an action waveform, such as Figure 3 shown.

[0076] In Example 2, the high-speed synchronous acquisition module 4 is usually in a pre-sampling state, and pre-samples 7 action currents and 1 line voltage at a sampling frequency of 50kHz. The data is put into FIFO. The FIFO buffer of each channel is 10ms long and can store 500 points of data. The acquisition frequency is 50kHz, which corresponds to 20us to collect 1 point, and 500 points correspond to 10ms.

[0077] The pre-sampled 10ms current data with 500 points is divided into 10 equal parts from No. 1 to No. 10 at 1ms intervals. The difference calculation is performed from the starting point to the end point on the 50-point data of the latter part (such as No. 2) and the 50-point data of the previous part (such as No. 1). The default difference trigger threshold is 10A, and the number of continuous trigger points is 10. In order to prevent false triggering, the pre-sampled data is latched only when it is detected that 10 consecutive data points exceed the threshold; when the trigger condition is met, the 500-point data in the current FIFO is latched. If the 10 consecutive data points are greater than 10A, the pre-sampled data is latched. The above pre-sampled data is continuously updated over time, and latching can ensure that the complete action waveform is stored.

[0078] When the trigger condition is met, the high-speed synchronous acquisition module 4 switches from the pre-sampling mode to the trigger acquisition mode; the high-speed synchronous acquisition module 4 continuously acquires 3500 points of data for a 70ms waveform, and combined with the pre-sampling data, each channel has a total of 4000 points of data; the action data is grouped in chronological order, and a maximum of 20 groups are stored, each group of 8 waveform data (7 action currents and 1 line voltage). After the trigger acquisition is completed, the high-speed synchronous acquisition module 4 returns to the pre-sampling mode.

[0079] The device uses a three-color integrated signal light to indicate the operating status of each column of the arrester group. There are 7 three-color indicator lights on the fault location host of this solution, which indicate the status of each of the 7 columns of arresters. Green represents normal, yellow represents degradation, and red represents failure. The arrangement order of the 7 indicator lights is consistent with the installation order of each column of the arrester. When a column of arrester fails, the color of the indicator light of the column turns red, realizing the location of the arrester fault. The device also has a remote data transmission function to realize the perception of the operating status of the DC parallel arrester group. The above functions ensure the safe operation of UHV DC equipment.

[0080] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A method for locating faults in a DC multi-column parallel arrester in operation, characterized in that: It includes the following steps: The DC leakage current of each column lightning arrester is collected by a DC leakage current sensor (1); The DC line voltage of the line voltage divider connected in parallel with the lightning arrester in the DC field of the converter station is collected by a line voltage sensor (2); The operating current of each column lightning arrester is collected by an operating current sensor (3); The insulation resistance of each column lightning arrester under the operating voltage is calculated by the DC line voltage of the line voltage divider and the DC leakage current of each column lightning arrester. The insulation resistance of each column lightning arrester under the operating voltage and the factory insulation resistance of the corresponding column lightning arrester are used to determine the insulation resistance status of each column lightning arrester. The action resistance value of the corresponding column lightning arrester is calculated by the action current of each column lightning arrester; the average action resistance of the lightning arrester is calculated according to the action resistance value of each column lightning arrester; the residual voltage at the peak point of the action current of each column lightning arrester is used to calculate the residual pressure resistance under the action current of each column lightning arrester; the state of the dynamic resistance of each column lightning arrester is determined by the action resistance value of each column lightning arrester, the average action resistance of the lightning arrester, the residual pressure resistance under the action current of each column lightning arrester and the maximum change resistance value of each column lightning arrester.

2. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The DC leakage current sensor (1) is connected in parallel to the two ends of the action current counter of each column lightning arrester, and the low impedance input circuit of the DC leakage current sensor (1) is in a normally open state. When the preset collection time is reached, the DC leakage current sensor (1) collects the DC leakage current of each column lightning arrester through the low impedance input circuit.

3. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The DC leakage current sensor (1) is used to measure the DC leakage current of the arrester by utilizing the AC signal suppression and DC gain adjustment functions.

4. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The coil of the action current sensor (3) is sleeved on the grounding down conductor below the lightning arrester, and the action current signal is sampled by using the Rogowski coil.

5. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The DC line voltage collected by the line voltage sensor (2) and the action current of each column lightning arrester collected by the action current sensor (3) are continuously pre-sampled and triggered for sampling by a high-speed synchronous acquisition module (4), and the pre-sampled data are placed in a first-in-first-out queue of a fixed length. When it is detected that the action current signal of any column lightning arrester meets a preset trigger condition, the high-speed synchronous acquisition module (4) is started to collect a continuous waveform of the action current signal of a preset time length; the high-speed synchronous acquisition module (4) arranges the continuous waveform of the action current signal, the DC line voltage collected by the line voltage sensor (2) and the action current of each column lightning arrester collected by the action current sensor (3) in the order of sampling time to form an action waveform.

6. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The specific method for judging the insulation resistance status of each column arrester is as follows: When R 运行 ≥R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is ≈ the preset slope k, the insulation state of the column arrester is normal, where R 运行 is the insulation resistance of a column arrester under the operating voltage, R 参考 The factory insulation resistance of the corresponding column arrester; When R 运行 ≥R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is less than the preset slope k, the insulation resistance of the column arrester is degraded; When R 运行 <R 参考 , and the insulation resistance R 运行 When the slope of the curve fluctuating with the time axis is less than the preset slope k, there is a fault in the insulation resistance of the column lightning arrester.

7. The fault location method of a DC multi-column parallel arrester in operation according to claim 1, characterized in that: The specific method for judging the dynamic resistance state of each column arrester by using the action resistance value of each column arrester, the average action resistance value of the arrester, the residual voltage resistance under the action current of each column arrester and the maximum change resistance value of each column arrester is as follows: When | R 动作 -R 平均 |<ΔR, and |R 动作 -R 残压 |<ΔR, the dynamic resistance state of the column arrester is normal, where R 动作 is the operating resistance value of a column arrester, R 平均 is the average value of the arrester action resistance, R 残压 is the residual voltage resistance of the column arrester under the operating current, ΔR is the maximum variable resistance value of the column arrester; When | R 动作 -R 平均 |>ΔR, and |R 动作 -R 残压 |<ΔR, the column arrester is degraded; When | R 动作 -R 平均 |>ΔR, and |R 动作 -R 残压 |>ΔR, the column arrester is faulty.

8. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The specific method for calculating the average value of the arrester action resistance according to the action resistance value of each column arrester is: The calculated action resistance values ​​of all arresters are sorted from large to small, the largest and smallest resistance values ​​are removed, and the average of the intermediate action resistance values ​​is calculated to obtain the average action resistance value of the arrester.

9. The fault location method of a DC multi-column parallel arrester in operation state according to claim 1, characterized in that: The method for calculating the factory insulation resistance of the lightning arrester is: using the leakage current corresponding to the DC reference voltage of the lightning arrester as a parameter to calculate the factory insulation resistance of each column lightning arrester.

10. A fault location device for a DC multi-column parallel arrester in operation, characterized in that it include: The DC leakage current sensor (1) is used to collect the DC leakage current of each column lightning arrester; The line voltage sensor (2) is used to collect the DC line voltage of the line voltage divider connected in parallel with the lightning arrester in the DC field of the converter station; The operating current sensor (3) is used to collect the operating current of each column lightning arrester; The fault location host (5) is used to calculate the insulation resistance of each column lightning arrester under the operating voltage through the DC line voltage of the line voltage divider and the DC leakage current of each column lightning arrester, and to determine the state of the insulation resistance of each column lightning arrester by using the insulation resistance of each column lightning arrester under the operating voltage and the factory insulation resistance of the corresponding column lightning arrester; The fault location host (5) is used to calculate the action resistance value of the corresponding column lightning arrester through the action current of each column lightning arrester; calculate the average action resistance of the lightning arrester according to the action resistance value of each column lightning arrester; calculate the residual pressure resistance of each column lightning arrester under the action current by using the residual voltage at the peak point of the action current of each column lightning arrester; and judge the state of the dynamic resistance of each column lightning arrester by using the action resistance value of each column lightning arrester, the average action resistance of the lightning arrester, the residual pressure resistance of each column lightning arrester under the action current and the maximum change resistance value of each column lightning arrester.

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