A method for monitoring partial discharge of a power cable joint

Abstract

The application provides a power cable joint partial discharge monitoring method and system, by dividing the power cable into multiple monitoring sections, obtaining a reference current attenuation coefficient in an initial stage, considering the influence of temperature change on current attenuation in an operation stage, calculating an actual current attenuation coefficient, thereby accurately predicting the expected current of each joint, by comparing the difference between the expected current and the measured current, the partial discharge condition of the power cable joint can be accurately monitored, and the monitoring accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, specifically to a method for monitoring partial discharge at power cable joints. Background Technology

[0002] Partial discharge (PD) in power cable joints refers to the localized, intermittent, and weak discharge phenomenon inside the cable joint caused by insulation defects or uneven electric field distribution. This discharge will not immediately cause complete insulation breakdown, but its long-term presence will gradually degrade the insulation material, eventually leading to joint failure or even cable system malfunction.

[0003] Currently, partial discharge monitoring of power cable joints commonly employs methods such as high-frequency current testing (HFCT), ultrasonic testing, ultra-high frequency (UHF) testing, or infrared thermal imaging. However, after the power cable is laid, the necessary conditions for these monitoring methods are often unavailable. For example, many joints of submarine power cables and large urban power cables are located in deep sea or buried underground. Furthermore, these monitoring methods often cannot effectively eliminate the influence of ambient temperature changes on current attenuation, leading to inaccurate monitoring results. Therefore, there is an urgent need to provide a suitable solution for partial discharge monitoring of power cable joints that addresses these issues. Summary of the Invention

[0004] The technical problem this invention aims to solve is that existing methods for monitoring partial discharge in power cable joints lack accuracy, making it difficult to accurately identify partial discharge conditions, especially when the ambient temperature of the cable laying environment varies significantly. These methods cannot effectively eliminate the influence of temperature changes on current attenuation, leading to inaccurate monitoring results. Furthermore, for cable joints in deep-sea or deeply buried locations such as submarine power cables and large urban power cables, existing monitoring methods such as high-frequency current testing (HFCT), ultrasonic testing, ultra-high frequency (UHF) testing, or infrared thermal imaging often cannot provide the necessary implementation conditions. Therefore, there is an urgent need to provide a suitable solution for monitoring partial discharge in power cable joints that addresses these issues.

[0005] On one hand, embodiments of the present invention provide a method for monitoring partial discharge at power cable joints, the method comprising:

[0006] The target power cable is divided into multiple monitoring segments based on its starting point, ending point, and all joints it contains, and the monitoring segment to which each joint belongs is determined.

[0007] For each monitoring segment, in the initial stage after the target power cable is laid, the first starting current, the first ending current and the reference temperature of the monitoring segment are obtained, and the reference current attenuation coefficient of the monitoring segment is determined based on the first starting current, the first ending current and the cable length of the monitoring segment.

[0008] During the operation phase after the target power cable is laid, the second starting current and measured temperature of the monitoring segment are obtained. Based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, the actual current attenuation coefficient of the monitoring segment is determined. Then, based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each joint in the monitoring segment is determined.

[0009] For each joint, based on the measured current and the expected current of the joint, the partial discharge condition corresponding to the joint is determined, and based on the partial discharge conditions corresponding to each joint included in the target power cable, the partial discharge condition corresponding to the target power cable is determined.

[0010] In an optional embodiment of the present invention, dividing the target power cable into multiple monitoring segments based on its start point, end point, and all included joints includes:

[0011] Based on the laying environment of the target power cable, determine the temperature variation segment of the target power cable;

[0012] Along the direction from the starting point to the ending point of the target power cable, the starting point, ending point, and all joints of the target power cable are included in each temperature change segment to obtain multiple monitoring segments, such that the starting point of the first monitoring segment is the starting point of the target power cable, the ending point of the last monitoring segment is the ending point of the target power cable, and the starting point and ending point of the other monitoring segments are the corresponding joints.

[0013] In an optional embodiment of the present invention, obtaining the first starting current, the first ending current, and the reference temperature of the monitoring segment includes:

[0014] The sensor-collected current at the starting point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first starting current, and the sensor-collected current at the ending point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first ending current. The reference temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the initial stage after the target power cable is laid.

[0015] In an optional embodiment of the present invention, the reference current attenuation coefficient of the monitoring segment is determined based on the first starting current, the first ending current, and the cable length of the monitoring segment, using the following formula:

[0016]

[0017] in, The reference current attenuation coefficient is... The length of the cable in the monitored segment is [length]. The first starting current, This is the first endpoint current.

[0018] In an optional embodiment of the present invention, obtaining the second starting current and measured temperature of the monitoring segment includes:

[0019] The sensor-collected current at the starting point of the monitoring segment during the operation phase after the target power cable is laid is used as the second starting current. The measured temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the operation phase after the target power cable is laid.

[0020] In an optional embodiment of the present invention, the determination of the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature, and the reference current attenuation coefficient is achieved by the following formula:

[0021]

[0022] in, The actual current attenuation coefficient is... The reference temperature is... The measured temperature is... The temperature coefficient of conductor resistance of the target power cable material;

[0023] The expected current corresponding to each joint in the monitoring segment is determined based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, using the following formula:

[0024]

[0025] in, The expected current of the k-th connector in the monitoring segment. This is the second starting current. The length of the cable from the k-th connector of the monitoring segment to the starting point of the monitoring segment is denoted as .

[0026] In an optional embodiment of the present invention, determining the partial discharge condition corresponding to each joint based on the measured current and the expected current of the joint, and determining the partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable, includes:

[0027] For each connector, if the difference between the expected current and the measured current of the connector is not less than a preset threshold, then the connector is determined to have partial discharge.

[0028] If the number of joints with partial discharge in the target power cable is not less than a preset number, then the target power cable is determined to require partial discharge warning.

[0029] Secondly, embodiments of the present invention provide a partial discharge monitoring system for power cable joints, the system comprising:

[0030] The monitoring segment acquisition module is used to divide the target power cable into multiple monitoring segments based on the starting point, ending point, and all joints contained therein, and to determine the monitoring segment to which each joint belongs.

[0031] The reference current attenuation coefficient acquisition module is used to acquire the first starting current, the first ending current and the reference temperature of each monitoring segment in the initial stage after the target power cable is laid, and to determine the reference current attenuation coefficient of the monitoring segment based on the first starting current, the first ending current and the cable length of the monitoring segment.

[0032] The expected current acquisition module is used to acquire the second starting current and measured temperature of the monitoring segment during the operation phase after the target power cable is laid, and to determine the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature and the reference current attenuation coefficient, and then to determine the expected current corresponding to each joint included in the monitoring segment based on the second starting current, the actual current attenuation coefficient and the cable length from each joint included in the monitoring segment to the starting point of the monitoring segment.

[0033] The partial discharge condition determination module is used to determine the partial discharge condition corresponding to each joint based on the measured current and the expected current of the joint, and to determine the partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable.

[0034] In an optional embodiment of the present invention, dividing the target power cable into multiple monitoring segments based on its start point, end point, and all included joints includes:

[0035] Based on the laying environment of the target power cable, determine the temperature variation segment of the target power cable;

[0036] Along the direction from the starting point to the ending point of the target power cable, the starting point, ending point, and all joints of the target power cable are included in each temperature change segment to obtain multiple monitoring segments, such that the starting point of the first monitoring segment is the starting point of the target power cable, the ending point of the last monitoring segment is the ending point of the target power cable, and the starting point and ending point of the other monitoring segments are the corresponding joints.

[0037] In an optional embodiment of the present invention, obtaining the first starting current, the first ending current, and the reference temperature of the monitoring segment includes:

[0038] The sensor-collected current at the starting point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first starting current, and the sensor-collected current at the ending point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first ending current. The reference temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the initial stage after the target power cable is laid.

[0039] In an optional embodiment of the present invention, the reference current attenuation coefficient of the monitoring segment is determined based on the first starting current, the first ending current, and the cable length of the monitoring segment, using the following formula:

[0040]

[0041] in, The reference current attenuation coefficient is... The length of the cable in the monitored segment is [length]. The first starting current, This is the first endpoint current.

[0042] In an optional embodiment of the present invention, obtaining the second starting current and measured temperature of the monitoring segment includes:

[0043] The sensor-collected current at the starting point of the monitoring segment during the operation phase after the target power cable is laid is used as the second starting current. The measured temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the operation phase after the target power cable is laid.

[0044] In an optional embodiment of the present invention, the determination of the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature, and the reference current attenuation coefficient is achieved by the following formula:

[0045]

[0046] in, The actual current attenuation coefficient is... The reference temperature is... The measured temperature is... The temperature coefficient of conductor resistance of the target power cable material;

[0047] The expected current corresponding to each joint in the monitoring segment is determined based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, using the following formula:

[0048]

[0049] in, The expected current of the k-th connector in the monitoring segment. This is the second starting current. The length of the cable from the k-th connector of the monitoring segment to the starting point of the monitoring segment is denoted as .

[0050] In an optional embodiment of the present invention, determining the partial discharge condition corresponding to each joint based on the measured current and the expected current of the joint, and determining the partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable, includes:

[0051] For each connector, if the difference between the expected current and the measured current of the connector is not less than a preset threshold, then the connector is determined to have partial discharge.

[0052] If the number of joints with partial discharge in the target power cable is not less than a preset number, then the target power cable is determined to require partial discharge warning.

[0053] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement any of the above-described methods for monitoring partial discharge of power cable joints.

[0054] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described methods for monitoring partial discharge of power cable joints.

[0055] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements any of the above-described methods for monitoring partial discharge of power cable joints.

[0056] The solution provided in this application divides the power cable into multiple monitoring segments and obtains a reference current attenuation coefficient in the initial stage. During the operation phase, it considers the impact of temperature changes on current attenuation and calculates the actual current attenuation coefficient, thereby accurately predicting the expected current of each joint. By comparing the difference between the expected current and the measured current, it can accurately monitor the partial discharge of power cable joints, improving monitoring accuracy. This invention, by considering the impact of temperature changes on current attenuation, eliminates interference from ambient temperature variations, making the monitoring results more reliable, and is particularly suitable for situations where the cable laying environment has large temperature variations. By dividing the cable into multiple monitoring segments, this invention can accurately locate the joint where partial discharge occurs. By comparing the difference between the expected current and the measured current, it can promptly detect partial discharge problems, realizing the early warning function of power cables and improving the safety and reliability of the power system. This invention is applicable to various partial discharge monitoring scenarios for power cable joints, especially for monitoring cable joints in deep-sea or deeply buried areas such as submarine power cables and large urban power supply cables, solving the problem that existing monitoring methods cannot be implemented in special environments. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0058] Figure 1 A flowchart illustrating a method for monitoring partial discharge at a power cable joint provided by the present invention;

[0059] Figure 2 A structural block diagram of a partial discharge monitoring system for power cable joints provided by the present invention;

[0060] Figure 3 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0061] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0062] Figure 1 This is a flowchart illustrating a method for monitoring partial discharge at a power cable joint, as provided in an embodiment of the present invention. Figure 1 As shown, the method may include:

[0063] Step S101: Divide the target power cable into multiple monitoring segments based on the starting point, ending point, and all joints it contains, and determine the monitoring segment to which each joint belongs.

[0064] The system includes sensors for collecting current values ​​at the starting point, ending point, and each joint of the target power cable. These sensors can be flexible Rogowski coils, etc. The system also includes sensors for collecting temperature values ​​at preset positions on the outer sheath of the target power cable and at each joint. These sensors can be distributed optical fiber sensors (DTS). All of these sensors transmit the collected data to the corresponding monitoring terminal through appropriate transmission methods. The monitoring terminal is used to execute the monitoring method provided in this solution.

[0065] In addition, before the target power cable is laid, the cable length between each joint and the starting point will be recorded, so that the cable length required for subsequent calculations can be obtained during the subsequent monitoring process.

[0066] Specifically, considering the complex operating conditions of large power cables after installation, the temperature environment varies along different segments of the cable. Temperature significantly affects current transmission characteristics, causing fluctuations in current at joints at different cable lengths. Therefore, to ensure the accuracy of partial discharge monitoring, the influence of temperature must be eliminated when monitoring partial discharge at joints. The embodiment of this invention requires dividing the target power cable into segments based on the temperature environment along its length after installation. In other words, cable segments with similar or identical temperature conditions need to be grouped into the same monitoring segment, thereby allowing for different monitoring of joints under different temperature conditions.

[0067] For example, a target power cable contains four joints, numbered sequentially from start to finish: Joint 1, Joint 2, Joint 3, Joint 4, Joint 5, and Joint 6. The target power cable is divided into two monitoring segments, numbered sequentially from start to finish: Monitoring Segment a, Monitoring Segment b, and Monitoring Segment c. Monitoring segment a includes the start of the target power cable, Joint 1, and Joint 2. Therefore, the start of monitoring segment a is the start of the target power cable, and the end is Joint 2. In this segment, Joints 1 and 2 are monitored. Monitoring segment b includes Joints 2, 3, and 4. Therefore, the start of monitoring segment b is Joint 2, and the end is Joint 4. In this segment, Joints 3 and 4 are monitored. Monitoring segment c includes Joints 4, 5, 6, and the end of the target power cable. Therefore, the start of monitoring segment c is Joint 4, and the end is the end of the power cable. In this segment, Joints 5 and 6 are monitored. Understandably, the specific method of dividing the monitoring segments needs to be based on the actual laying environment. The starting point of the divided monitoring segment should be the starting point of the target power cable or the corresponding joint, and the ending point of the divided monitoring segment should be the ending point of the target power cable or the corresponding joint. In this way, the starting current and ending current of the monitoring segment can be obtained, which can be used to calculate the basic current attenuation coefficient of the monitoring segment, as well as to calculate the expected current of the subsequent joints of the monitoring segment.

[0068] Step S102: For each monitoring segment, in the initial stage after the target power cable is laid, the first starting current, the first ending current and the reference temperature of the monitoring segment are obtained, and the reference current attenuation coefficient of the monitoring segment is determined based on the first starting current, the first ending current and the cable length of the monitoring segment.

[0069] Specifically, the initial stage typically refers to the period immediately after the power cable has been laid and put into use. At this time, the cable and its joints are in good condition, without aging or damage. During this stage, by installing current sensors at the start and end points of the monitoring segment, the values ​​of the first starting current and the first ending current can be obtained. Simultaneously, by installing temperature sensors at various preset locations and joints within the monitoring segment, the reference temperature can be obtained. This reference temperature is the temperature of the segment corresponding to the initial stage and serves as a benchmark for eliminating the influence of temperature in subsequent monitoring.

[0070] Step S103: During the operation phase after the target power cable is laid, the second starting current and measured temperature of the monitoring segment are obtained. Based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, the actual current attenuation coefficient of the monitoring segment is determined. Then, based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each joint in the monitoring segment is determined.

[0071] Specifically, the operational phase refers to the period when the power cable is running normally. At this stage, the cable may have been in operation for some time, and aging or damage may have occurred at the joints. During this phase, by installing a current sensor at the starting point of the monitoring segment, the value of the second starting current can be obtained. Simultaneously, by installing temperature sensors at various preset locations and joints within the monitoring segment, the measured temperature values ​​can be obtained.

[0072] Step S104: For each joint, based on the measured current of the joint and the expected current, determine the partial discharge condition corresponding to the joint, and based on the partial discharge conditions corresponding to each joint included in the target power cable, determine the partial discharge condition corresponding to the target power cable.

[0073] Specifically, by comparing the measured current at the joint with the expected current, it can be determined whether there is partial discharge at the joint. If the difference between the measured current and the expected current is large, it indicates that there may be partial discharge at the joint, requiring further inspection and maintenance.

[0074] The solution provided in this application divides the power cable into multiple monitoring segments and obtains a reference current attenuation coefficient in the initial stage. During the operation phase, it considers the impact of temperature changes on current attenuation and calculates the actual current attenuation coefficient, thereby accurately predicting the expected current of each joint. By comparing the difference between the expected current and the measured current, it can accurately monitor the partial discharge of power cable joints, improving monitoring accuracy. This invention, by considering the impact of temperature changes on current attenuation, eliminates interference from ambient temperature variations, making the monitoring results more reliable, and is particularly suitable for situations where the cable laying environment has large temperature variations. By dividing the cable into multiple monitoring segments, this invention can accurately locate the joint where partial discharge occurs. By comparing the difference between the expected current and the measured current, it can promptly detect partial discharge problems, realizing the early warning function of power cables and improving the safety and reliability of the power system. This invention is applicable to various partial discharge monitoring scenarios for power cable joints, especially for monitoring cable joints in deep-sea or deeply buried areas such as submarine power cables and large urban power supply cables, solving the problem that existing monitoring methods cannot be implemented in special environments.

[0075] In an optional embodiment of the present invention, dividing the target power cable into multiple monitoring segments based on its start point, end point, and all included joints includes:

[0076] Based on the laying environment of the target power cable, determine the temperature variation segment of the target power cable;

[0077] Along the direction from the starting point to the ending point of the target power cable, the starting point, ending point, and all joints of the target power cable are included in each temperature change segment to obtain multiple monitoring segments, such that the starting point of the first monitoring segment is the starting point of the target power cable, the ending point of the last monitoring segment is the ending point of the target power cable, and the starting point and ending point of the other monitoring segments are the corresponding joints.

[0078] Specifically, in practical applications, the laying environment of power cables may affect the temperature distribution of the cables, thereby affecting the current transmission characteristics. Therefore, when dividing monitoring segments, the impact of the cable laying environment on temperature needs to be considered. For example, if part of the cable is laid underground and part is laid above ground, the temperature of the underground part and the above-ground part may differ significantly, requiring separate division into different temperature variation segments.

[0079] In an optional embodiment of the present invention, obtaining the first starting current, the first ending current, and the reference temperature of the monitoring segment includes:

[0080] The sensor-collected current at the starting point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first starting current, and the sensor-collected current at the ending point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first ending current. The reference temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the initial stage after the target power cable is laid.

[0081] Specifically, in the initial stage after the power cable is laid, current sensors are installed at the start and end points of the monitoring segment to obtain the values ​​of the first starting current and the first ending current. At the same time, temperature sensors are installed at various preset locations and joints of the monitoring segment to obtain the temperature values ​​at each point. Then, the reference temperature is obtained by calculating the average or weighted average of these temperature values.

[0082] In one optional embodiment of this application, the reference current attenuation coefficient of the monitoring segment is determined based on the first starting current, the first ending current, and the cable length of the monitoring segment, using the following formula:

[0083]

[0084] in, The reference current attenuation coefficient is... The length of the cable in the monitored segment is [length]. The first starting current, This is the first endpoint current.

[0085] In one optional embodiment of this application, obtaining the second starting current and measured temperature of the monitoring segment includes:

[0086] The sensor-collected current at the starting point of the monitoring segment during the operation phase after the target power cable is laid is used as the second starting current. The measured temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the operation phase after the target power cable is laid.

[0087] Specifically, during the normal operation of the power cable, the value of the second starting current can be obtained by installing a current sensor at the starting point of the monitoring segment. At the same time, the temperature values ​​at each point can be obtained by installing temperature sensors at various preset locations and joints of the monitoring segment. Then, the measured temperature is obtained by calculating the average or weighted average of these temperature values.

[0088] In an optional embodiment of the present invention, the determination of the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature, and the reference current attenuation coefficient is achieved by the following formula:

[0089]

[0090] in, The actual current attenuation coefficient is... The reference temperature is... The measured temperature is... The temperature coefficient of conductor resistance of the target power cable material;

[0091] The expected current corresponding to each joint in the monitoring segment is determined based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, using the following formula:

[0092]

[0093] in, The expected current of the k-th connector in the monitoring segment. This is the second starting current. The length of the cable from the k-th connector of the monitoring segment to the starting point of the monitoring segment is denoted as .

[0094] In an optional embodiment of the present invention, determining the partial discharge condition corresponding to each joint based on the measured current and the expected current of the joint, and determining the partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable, includes:

[0095] For each connector, if the difference between the expected current and the measured current of the connector is not less than a preset threshold, then the connector is determined to have partial discharge.

[0096] If the number of joints with partial discharge in the target power cable is not less than a preset number, then the target power cable is determined to require partial discharge warning.

[0097] Specifically, in practical applications, the preset threshold can be set according to factors such as the type, specifications, and operating environment of the power cable. For example, for a certain type of power cable, the preset threshold can be set to 5% of the expected current. If the difference between the measured current at the joint and the expected current exceeds 5% of the expected current, the joint is considered to have partial discharge.

[0098] Similarly, the preset quantity can be set based on factors such as the total length of the power cable, the total number of joints, and their importance. For example, for a power cable with 10 joints, the preset quantity can be set to 2. If partial discharge is detected at two or more joints, a partial discharge warning needs to be issued for the entire power cable.

[0099] Figure 2 This invention provides a partial discharge monitoring system for cable joints, the system comprising:

[0100] The monitoring segment acquisition module 201 is used to divide the target power cable into multiple monitoring segments based on the starting point, ending point and all joints contained therein, and to determine the monitoring segment to which each joint belongs.

[0101] The reference current attenuation coefficient acquisition module 202 is used to acquire the first starting current, the first ending current and the reference temperature of each monitoring segment in the initial stage after the target power cable is laid, and to determine the reference current attenuation coefficient of the monitoring segment based on the first starting current, the first ending current and the cable length of the monitoring segment.

[0102] The expected current acquisition module 203 is used to acquire the second starting current and measured temperature of the monitoring segment during the operation phase after the target power cable is laid, and to determine the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature and the reference current attenuation coefficient, and then to determine the expected current corresponding to each joint included in the monitoring segment based on the second starting current, the actual current attenuation coefficient and the cable length from each joint included in the monitoring segment to the starting point of the monitoring segment.

[0103] The partial discharge condition determination module 204 is used to determine the partial discharge condition corresponding to each joint based on the measured current and the expected current of the joint, and to determine the partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable.

[0104] The solution provided in this application divides the power cable into multiple monitoring segments and obtains a reference current attenuation coefficient in the initial stage. During the operation phase, it considers the impact of temperature changes on current attenuation and calculates the actual current attenuation coefficient, thereby accurately predicting the expected current of each joint. By comparing the difference between the expected current and the measured current, it can accurately monitor the partial discharge of power cable joints, improving monitoring accuracy. This invention, by considering the impact of temperature changes on current attenuation, eliminates interference from ambient temperature variations, making the monitoring results more reliable, and is particularly suitable for situations where the cable laying environment has large temperature variations. By dividing the cable into multiple monitoring segments, this invention can accurately locate the joint where partial discharge occurs. By comparing the difference between the expected current and the measured current, it can promptly detect partial discharge problems, realizing the early warning function of power cables and improving the safety and reliability of the power system. This invention is applicable to various partial discharge monitoring scenarios for power cable joints, especially for monitoring cable joints in deep-sea or deeply buried areas such as submarine power cables and large urban power supply cables, solving the problem that existing monitoring methods cannot be implemented in special environments.

[0105] In an optional embodiment of the present invention, dividing the target power cable into multiple monitoring segments based on its start point, end point, and all included joints includes:

[0106] Based on the laying environment of the target power cable, determine the temperature variation segment of the target power cable;

[0107] Along the direction from the starting point to the ending point of the target power cable, the starting point, ending point, and all joints of the target power cable are included in each temperature change segment to obtain multiple monitoring segments, such that the starting point of the first monitoring segment is the starting point of the target power cable, the ending point of the last monitoring segment is the ending point of the target power cable, and the starting point and ending point of the other monitoring segments are the corresponding joints.

[0108] In an optional embodiment of the present invention, obtaining the first starting current, the first ending current, and the reference temperature of the monitoring segment includes:

[0109] The sensor-collected current at the starting point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first starting current, and the sensor-collected current at the ending point of the monitoring segment during the initial stage after the target power cable is laid is taken as the first ending current. The reference temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the initial stage after the target power cable is laid.

[0110] In an optional embodiment of the present invention, the reference current attenuation coefficient of the monitoring segment is determined based on the first starting current, the first ending current, and the cable length of the monitoring segment, using the following formula:

[0111]

[0112] in, The reference current attenuation coefficient is... The length of the cable in the monitored segment is [length]. The first starting current, This is the first endpoint current.

[0113] In an optional embodiment of the present invention, obtaining the second starting current and measured temperature of the monitoring segment includes:

[0114] The sensor-collected current at the starting point of the monitoring segment during the operation phase after the target power cable is laid is used as the second starting current. The measured temperature is determined based on the sensor-collected temperatures at each preset position and each joint of the monitoring segment during the operation phase after the target power cable is laid.

[0115] In an optional embodiment of the present invention, the determination of the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature, and the reference current attenuation coefficient is achieved by the following formula:

[0116]

[0117] in, The actual current attenuation coefficient is... The reference temperature is... The measured temperature is... The temperature coefficient of conductor resistance of the target power cable material;

[0118] The expected current corresponding to each joint in the monitoring segment is determined based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, using the following formula:

[0119]

[0120] in, The expected current of the k-th connector in the monitoring segment. This is the second starting current. The length of the cable from the k-th connector of the monitoring segment to the starting point of the monitoring segment is denoted as .

[0121] In an optional embodiment of the present invention, determining the partial discharge condition corresponding to each joint based on the measured current and the expected current of the joint, and determining the partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable, includes:

[0122] For each connector, if the difference between the expected current and the measured current of the connector is not less than a preset threshold, then the connector is determined to have partial discharge.

[0123] If the number of joints with partial discharge in the target power cable is not less than a preset number, then the target power cable is determined to require partial discharge warning.

[0124] Figure 3 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 3As shown, the electronic device may include: a processor 310, a communication interface 320, a memory 330, and a communication bus 340, wherein the processor 310, the communication interface 320, and the memory 330 communicate with each other through the communication bus 340. The processor 310 can call logical instructions in the memory 330 to execute a method for monitoring partial discharge of power cable joints. The method includes: dividing the target power cable into multiple monitoring segments based on the starting point, ending point, and all joints contained therein, and determining the monitoring segment to which each joint belongs; for each monitoring segment, in the initial stage after the target power cable is laid, acquiring the first starting current, the first ending current, and the reference temperature of the monitoring segment, and determining the reference current attenuation coefficient of the monitoring segment based on the first starting current, the first ending current, and the cable length of the monitoring segment; in the operation stage after the target power cable is laid, acquiring the partial discharge monitoring method for power cable joints; and in the operation stage after the target power cable is laid, acquiring the partial discharge monitoring method for power cable joints. The second starting current and measured temperature of the monitoring segment are used. Based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, the actual current attenuation coefficient of the monitoring segment is determined. Then, based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each joint in the monitoring segment is determined. For each joint, based on the measured current and the expected current of the joint, the partial discharge condition corresponding to the joint is determined. Based on the partial discharge conditions corresponding to each joint in the target power cable, the partial discharge condition corresponding to the target power cable is determined.

[0125] Furthermore, the logical instructions in the aforementioned memory 330 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0126] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the power cable joint partial discharge monitoring method provided by the above methods. The method includes: dividing the target power cable into multiple monitoring segments based on the starting point, ending point, and all joints contained therein, and determining the monitoring segment to which each joint belongs; for each monitoring segment, in the initial stage after the target power cable is laid, acquiring the first starting current, the first ending current, and the reference temperature of the monitoring segment, and determining the monitoring... The reference current attenuation coefficient of the segment; during the operation phase after the target power cable is laid, the second starting current and measured temperature of the monitoring segment are obtained, and based on the measured temperature, the reference temperature and the reference current attenuation coefficient, the actual current attenuation coefficient of the monitoring segment is determined. Then, based on the second starting current, the actual current attenuation coefficient and the cable length from each joint included in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each joint included in the monitoring segment is determined. For each joint, based on the measured current of the joint and the expected current, the partial discharge condition corresponding to the joint is determined, and based on the partial discharge condition corresponding to each joint included in the target power cable, the partial discharge condition corresponding to the target power cable is determined.

[0127] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method for monitoring partial discharge of power cable joints provided by the methods described above. The method includes: dividing the target power cable into multiple monitoring segments based on its starting point, ending point, and all included joints, and determining the monitoring segment to which each joint belongs; for each monitoring segment, in the initial stage after the target power cable is laid, acquiring a first starting current, a first ending current, and a reference temperature of the monitoring segment, and determining a reference current attenuation coefficient of the monitoring segment based on the first starting current, the first ending current, and the cable length of the monitoring segment; and in the... During the operation phase after the target power cable is laid, the second starting current and measured temperature of the monitoring segment are obtained. Based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, the actual current attenuation coefficient of the monitoring segment is determined. Then, based on the second starting current, the actual current attenuation coefficient, and the cable length from each joint in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each joint in the monitoring segment is determined. For each joint, based on the measured current and the expected current of the joint, the partial discharge condition corresponding to the joint is determined. Based on the partial discharge condition corresponding to each joint in the target power cable, the partial discharge condition corresponding to the target power cable is determined.

[0128] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0129] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for monitoring partial discharge in a power cable joint, characterized in that, The method comprises: dividing the target power cable into a plurality of monitoring segments according to the start point, end point and each joint of the target power cable, and determining the monitoring segment to which each joint belongs; for each monitoring segment, obtaining a first start point current, a first end point current and a reference temperature of the monitoring segment at an initial stage after laying of the target power cable, and determining a reference current attenuation coefficient of the monitoring segment based on the first start point current, the first end point current and a cable length of the monitoring segment; at an operation stage after laying of the target power cable, obtaining a second start point current and a measured temperature of the monitoring segment, and determining an actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature and the reference current attenuation coefficient, and then determining an expected current corresponding to each joint included in the monitoring segment based on the second start point current, the actual current attenuation coefficient and a cable length from each joint to the start point of the monitoring segment; for each joint, determining a partial discharge condition corresponding to the joint based on a measured current of the joint and the expected current, and determining a partial discharge condition corresponding to the target power cable based on the partial discharge conditions corresponding to each joint included in the target power cable.

2. The method of claim 1, wherein, The dividing of the target power cable into a plurality of monitoring segments according to the start point, end point and each joint of the target power cable comprises: determining temperature variation segments of the target power cable based on a laying environment of the target power cable; including the start point, end point and each joint of the target power cable into each temperature variation segment in a direction from the start point to the end point of the target power cable to obtain a plurality of monitoring segments, so that the start point of a first monitoring segment is the start point of the target power cable, the end point of a last monitoring segment is the end point of the target power cable, and the start point and end point of other monitoring segments are corresponding joints respectively.

3. The method of claim 1, wherein, The obtaining of the first start point current, first end point current and reference temperature of the monitoring segment comprises: acquiring a sensor collected current at an initial stage after laying of the target power cable as the first start point current, acquiring a sensor collected current at the end point of the monitoring segment at the initial stage after laying of the target power cable as the first end point current, and determining the reference temperature based on sensor collected temperatures at each preset position and each joint of the monitoring segment at the initial stage after laying of the target power cable.

4. The method of claim 1, wherein, The determination of the reference current attenuation coefficient of the monitoring segment based on the first start point current, the first end point current and the cable length of the monitoring segment is realized by the following formula: wherein, is the reference current decay coefficient, is the cable length of the monitoring section, is the first start point current, is the first end point current.

5. The method of claim 1, wherein, The obtaining of the second start point current and measured temperature of the monitoring segment comprises: acquiring a sensor collected current at an operation stage after laying of the target power cable as the second start point current, and determining the measured temperature based on sensor collected temperatures at each preset position and each joint of the monitoring segment at the operation stage after laying of the target power cable.

6. The method of claim 4, wherein, The actual current attenuation coefficient of the monitoring section is determined based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, by the following formula: wherein is the actual current decay coefficient, is the reference temperature, is the measured temperature, is the conductor resistance temperature coefficient of the target power cable material; The expected current of each joint included in the monitoring section is determined based on the second start point current, the actual current attenuation coefficient, and the cable length from each joint to the start point of the monitoring section, by the following formula: wherein, is the expected current for the kth joint of the monitored segment, is the second starting current, is the cable length from the kth joint of the monitored segment to the starting point of the monitored segment.

7. The method of claim 1, wherein, The partial discharge condition of each joint is determined based on the measured current and the expected current of the joint, and the partial discharge condition of the target power cable is determined based on the partial discharge conditions of each joint included in the target power cable, including: If the difference between the expected current and the measured current of each joint is not less than a preset threshold, it is determined that the joint has partial discharge. If the number of joints with partial discharge among all joints included in the target power cable is not less than a preset number, it is determined that the target power cable needs to be warned of partial discharge.

8. A power cable joint partial discharge monitoring system, characterized in that, The system comprises: A monitoring section acquisition module is configured to divide the target power cable into multiple monitoring sections with the start point, the end point, and each joint included in the target power cable, and determine the monitoring section to which each joint belongs; A reference current attenuation coefficient acquisition module is configured to, for each monitoring section, acquire the first start point current, the first end point current, and the reference temperature at an initial stage after the target power cable is laid, and determine the reference current attenuation coefficient of the monitoring section based on the first start point current, the first end point current, and the cable length of the monitoring section; An expected current acquisition module is configured to, at an operation stage after the target power cable is laid, acquire the second start point current and the measured temperature of the monitoring section, determine the actual current attenuation coefficient of the monitoring section based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, and determine the expected current of each joint included in the monitoring section based on the second start point current, the actual current attenuation coefficient, and the cable length from each joint to the start point of the monitoring section; A partial discharge condition determination module is configured to, for each joint, determine the partial discharge condition of the joint based on the measured current and the expected current of the joint, and determine the partial discharge condition of the target power cable based on the partial discharge conditions of each joint included in the target power cable.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the method of any one of claims 1 to 7. 10.A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the method of any one of claims 1 to 7. The computer program is executed by the processor to implement the method of any one of claims 1 to 7.

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