Power cable joint partial discharge monitoring method

Abstract

The invention provides a power cable joint partial discharge monitoring method and system, and the method comprises the steps: dividing a power cable into a plurality of monitoring segments, obtaining a reference current attenuation coefficient at an initial stage, considering the influence of temperature change on current attenuation at an operation stage, and calculating an actual current attenuation coefficient. Therefore, the expected current of each joint is accurately predicted, the partial discharge condition of the power cable joint can be accurately monitored by comparing the difference between the expected current and the actually measured current, and the monitoring accuracy is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of power cables, and in particular to a method for monitoring partial discharge of power cable joints. Background Art

[0002] Partial discharge (PD) in power cable joints refers to localized, intermittent, weak discharges caused by insulation defects or uneven electric field distribution within the joint. While this discharge won't immediately cause complete insulation breakdown, it can gradually degrade the insulation over time, ultimately leading to joint failure and even cable system failure.

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

[0004] The technical problem to be solved by the present invention is that the existing methods for monitoring partial discharge at power cable joints lack precision, making it difficult to accurately identify partial discharge at cable joints. This is especially true when the temperature of the cable laying environment varies significantly, as the effect of temperature changes on current attenuation cannot be effectively eliminated, resulting in inaccurate monitoring results. Furthermore, for deep-sea or deeply buried cable joints, such as submarine power cables and large urban power cables, existing monitoring methods such as high-frequency current detection (HFCT), ultrasonic testing, ultra-high frequency (UHF), or infrared thermal imaging often fail to provide the required implementation conditions. Therefore, there is an urgent need to provide a power cable joint partial discharge monitoring solution that can address the aforementioned issues.

[0005] In one aspect, an embodiment of the present invention provides a method for monitoring partial discharge of a power cable joint, the method comprising:

[0006] Divide the target power cable into multiple monitoring segments based on the starting point, end point, and joints of the target power cable, and determine the monitoring segment to which each joint belongs;

[0007] For each monitoring segment, in an initial stage after the target power cable is laid, obtaining a first starting point current, a first end point 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 point current, the first end point current, and the cable length of the monitoring segment;

[0008] During the operation phase after the target power cable is laid, obtaining the second starting point current and the measured temperature of the monitoring segment, and determining the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature, and the reference current attenuation coefficient; and further determining the expected current corresponding to each joint included in the monitoring segment based on the second starting point 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;

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

[0010] In an optional embodiment of the present invention, the target power cable is divided into multiple monitoring sections based on the starting point, end point and joints of the target power cable, including:

[0011] determining a temperature change section of the target power cable based on an installation environment of the target power cable;

[0012] Along the direction from the starting point to the end point of the target power cable, the starting point, end point and each joint contained in the target power cable are included in each temperature change segment to obtain multiple monitoring segments, so that the starting point of the first monitoring segment is the starting point of the target power cable, the end point of the last monitoring segment is the end point of the target power cable, and the starting points and end points of the other monitoring segments are the corresponding joints respectively.

[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 current collected by the sensor at the starting point of the monitoring segment in the initial stage after the target power cable is laid is used as the first starting point current, and the current collected by the sensor at the end point of the monitoring segment in the initial stage after the target power cable is laid is used as the first end point current. The reference temperature is determined based on the sensor collected temperatures at each preset position and each joint of the monitoring segment in 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 end current, and the cable length of the monitoring segment, and is implemented by the following formula:

[0016]

[0017] Wherein, α0 is the reference current attenuation coefficient, L is the cable length of the monitoring section, I s,1 is the first starting current, I d,1 is the first endpoint current.

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

[0019] The sensor collected current at the starting point of the monitoring node during the operation phase after the target power cable is laid is used as the second starting point current, and 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 actual current attenuation coefficient of the monitoring segment is determined based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, and is implemented by the following formula:

[0021]

[0022] Wherein, α(T) is the actual current attenuation coefficient, T0 is the reference temperature, T is the measured temperature, and β is the conductor resistance temperature coefficient of the target power cable material;

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

[0024]

[0025] Among them, I k (T) is the expected current of the kth joint of the monitoring segment, I s,2 is the second starting current, x k is the cable length from the kth connector of the monitoring segment to the starting point of the monitoring segment.

[0026] In an optional embodiment of the present invention, determining, for each joint, a partial discharge condition corresponding to the joint based on the measured current and the expected current of the joint, 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, includes:

[0027] For each joint, if the difference between the expected current and the measured current of the joint is not less than a preset threshold, it is determined that partial discharge exists in the joint;

[0028] If the number of joints with partial discharge among the 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 given a partial discharge warning.

[0029] In a second aspect, an embodiment of the present invention provides a power cable joint partial discharge monitoring system, the system comprising:

[0030] A monitoring segment acquisition module is used to divide the target power cable into multiple monitoring segments based on the starting point, end point and joints of the target power cable, and determine the monitoring segment to which each joint belongs;

[0031] a reference current attenuation coefficient acquisition module, configured to acquire, for each monitoring segment, a first starting point current, a first end point current, and a reference temperature of the monitoring segment in an initial stage after the target power cable is laid, and determine the reference current attenuation coefficient of the monitoring segment based on the first starting point current, the first end point current, and the cable length of the monitoring segment;

[0032] an expected current acquisition module, configured to obtain, during the operation phase after the target power cable is laid, the second starting point current and the measured temperature of the monitoring segment, 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 further determine the expected current corresponding to each joint included in the monitoring segment based on the second starting point 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] a partial discharge condition determination module for determining, for each joint, a partial discharge condition corresponding to the joint based on the 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.

[0034] In an optional embodiment of the present invention, the target power cable is divided into multiple monitoring sections based on the starting point, end point and joints of the target power cable, including:

[0035] determining a temperature change section of the target power cable based on an installation environment of the target power cable;

[0036] Along the direction from the starting point to the end point of the target power cable, the starting point, end point and each joint contained in the target power cable are included in each temperature change segment to obtain multiple monitoring segments, so that the starting point of the first monitoring segment is the starting point of the target power cable, the end point of the last monitoring segment is the end point of the target power cable, and the starting points and end points of the other monitoring segments are the corresponding joints respectively.

[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 current collected by the sensor at the starting point of the monitoring segment in the initial stage after the target power cable is laid is used as the first starting point current, and the current collected by the sensor at the end point of the monitoring segment in the initial stage after the target power cable is laid is used as the first end point current. The reference temperature is determined based on the sensor collected temperatures at each preset position and each joint of the monitoring segment in 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 end current, and the cable length of the monitoring segment, and is implemented by the following formula:

[0040]

[0041] Wherein, α0 is the reference current attenuation coefficient, L is the cable length of the monitoring section, I s,1 is the first starting current, I d,1 is the first endpoint current.

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

[0043] The sensor collected current at the starting point of the monitoring node during the operation phase after the target power cable is laid is used as the second starting point current, and 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 actual current attenuation coefficient of the monitoring segment is determined based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, and is implemented by the following formula:

[0045]

[0046] Wherein, α(T) is the actual current attenuation coefficient, T0 is the reference temperature, T is the measured temperature, and β is the conductor resistance temperature coefficient of the target power cable material;

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

[0048]

[0049] Among them, I k (T) is the expected current of the kth joint of the monitoring segment, I s,2 is the second starting current, x k is the cable length from the kth connector of the monitoring segment to the starting point of the monitoring segment.

[0050] In an optional embodiment of the present invention, determining, for each joint, a partial discharge condition corresponding to the joint based on the measured current and the expected current of the joint, 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, includes:

[0051] For each joint, if the difference between the expected current and the measured current of the joint is not less than a preset threshold, it is determined that partial discharge exists in the joint;

[0052] If the number of joints with partial discharge among the 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 given a partial discharge warning.

[0053] In a third aspect, the present invention further provides an electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, any of the above-mentioned methods for monitoring partial discharge of power cable joints is implemented.

[0054] In a fourth aspect, the present invention further 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-mentioned methods for monitoring partial discharge of power cable joints.

[0055] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-mentioned methods for monitoring partial discharge of power cable joints.

[0056] The solution provided by this application is to divide the power cable into multiple monitoring segments, obtain a baseline current attenuation coefficient in the initial stage, consider the impact of temperature changes on current attenuation during the operation stage, calculate the actual current attenuation coefficient, and accurately predict the expected current of each joint. By comparing the difference between the expected current and the measured current, the partial discharge of the power cable joint can be accurately monitored, thereby improving the monitoring accuracy. By considering the impact of temperature changes on current attenuation, the present invention eliminates the interference caused by ambient temperature changes, making the monitoring results more reliable, and is particularly suitable for situations where the temperature of the cable laying environment varies greatly. By dividing the cable into multiple monitoring segments, the present invention can accurately locate the joint position where partial discharge occurs. By comparing the difference between the expected current and the measured current, partial discharge problems can be discovered in a timely manner, realizing the early warning function of the power cable, and improving the safety and reliability of the power system. The present invention is applicable to various power cable joint partial discharge monitoring scenarios, especially for deep-sea or deeply buried cable joint monitoring such as submarine power cables and large-scale urban power supply cables, solving the problem that existing monitoring methods cannot be implemented in special environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 A schematic flow chart of a method for monitoring partial discharge of a power cable joint provided by the present invention;

[0059] Figure 2 This is a structural block diagram of a power cable joint partial discharge monitoring system provided by the present invention;

[0060] Figure 3 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0061] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0062] Figure 1 A flow chart of a method for monitoring partial discharge of a power cable joint provided by an embodiment of the present invention is shown as follows: Figure 1As shown, the method may include:

[0063] Step S101 : dividing the target power cable into a plurality of monitoring segments based on the starting point, the end point and the connectors of the target power cable, and determining the monitoring segment to which each connector belongs.

[0064] Among them, sensors for collecting current values are provided at the starting point, end point and each joint of the target power cable, which may be flexible Rogowski coils, etc., and sensors for collecting temperature values are provided at the preset position and each joint of the outer sheath of the target power cable, which may be distributed fiber sensors (DTS). These sensors transmit the collected data to the corresponding monitoring terminal through corresponding transmission means, and the monitoring terminal is used to execute the monitoring method provided by 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 operations can be calculated during subsequent monitoring.

[0066] Specifically, considering the complex operating conditions of large power cables after installation, different sections along their length correspond to different temperature environments. Temperature will significantly affect the current transfer characteristics, causing the current at joints at different cable lengths to fluctuate. Therefore, in order to ensure the accuracy of partial discharge monitoring, it is necessary to eliminate the temperature effect when monitoring partial discharge at joints. The embodiment of the present invention requires segmenting the target power cable based on the temperature environment along the length of the cable after installation. In other words, cable sections with similar or identical temperature conditions need to be divided into the same monitoring section, so that joints with different temperature conditions can be monitored differently.

[0067] For example, the target power cable contains 4 joints, which are: joint 1, joint 2, joint 3, joint 4, joint 5 and joint 6 from the starting point to the end point. According to the above method, the target power cable is divided into two monitoring segments, which are: monitoring segment a, monitoring segment b and monitoring segment c from the starting point to the end point. Among them, monitoring segment a contains the starting point, joint 1 and joint 2 of the target power cable, so the starting point of monitoring segment a is the starting point of the target power cable and the end point is joint 2. In this segment, joint 1 and joint 2 are monitored; monitoring segment b contains joint 2, joint 3 and joint 4, so the starting point of monitoring segment b is joint 2 and the end point is joint 4. In this monitoring segment, joint 3 and joint 4 are monitored; monitoring segment c contains joint 4, joint 5, joint 6 and the end point of the target power cable, so the starting point of monitoring segment c is joint 4 and the end point is the end point of the power cable. In this monitoring segment, joint 5 and joint 6 are monitored. It can be understood that the specific monitoring segment division method needs to be based on the actual laying environment. The starting point of the monitoring segment after division needs to be the starting point of the target power cable or the corresponding joint, and the end point of the monitoring segment after division needs to be the end point of the target power cable or the corresponding joint. In this way, the starting current and end point current of the monitoring segment can be obtained, which are used to calculate the basic current attenuation coefficient of the monitoring segment, as well as for calculating the expected current of subsequent joints of the monitoring segment.

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

[0069] Specifically, the initial stage generally refers to the period after the power cable has been laid and put into use. At this time, the cable and its connectors are in good condition, free of aging or damage. During this stage, current sensors are installed at the start and end of the monitoring segment to obtain the values of the first starting current and the first ending current. Simultaneously, temperature sensors are installed at various preset locations and connectors in the monitoring segment to obtain the value of the reference temperature. This reference temperature is the temperature of the segment corresponding to the initial stage and subsequently serves as a benchmark for eliminating temperature influences.

[0070] Step S103, during the operation phase after the target power cable is laid, obtain the second starting point current and the measured temperature of the monitoring segment, and 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 determine the expected current corresponding to each joint included in the monitoring segment based on the second starting point 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.

[0071] Specifically, the operational phase refers to the period during which the power cable is operating normally. During this phase, the cable may have been in operation for some time, and the joints may be aging or damaged. During this phase, current sensors installed at the starting point of the monitoring segment can obtain the current value at the second starting point. Furthermore, temperature sensors installed at various preset locations and joints in the monitoring segment can obtain the actual temperature value.

[0072] Step S104: for each joint, determining the partial discharge condition corresponding to the 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.

[0073] Specifically, by comparing the measured current at the joint with the expected current, it is possible to determine whether the joint is experiencing partial discharge. If the difference between the measured and expected currents is large, it indicates that partial discharge may be present at the joint and further inspection and maintenance are required.

[0074] The solution provided by this application is to divide the power cable into multiple monitoring segments, obtain a baseline current attenuation coefficient in the initial stage, consider the impact of temperature changes on current attenuation during the operation stage, calculate the actual current attenuation coefficient, and accurately predict the expected current of each joint. By comparing the difference between the expected current and the measured current, the partial discharge of the power cable joint can be accurately monitored, thereby improving the monitoring accuracy. By considering the impact of temperature changes on current attenuation, the present invention eliminates the interference caused by ambient temperature changes, making the monitoring results more reliable, and is particularly suitable for situations where the temperature of the cable laying environment varies greatly. By dividing the cable into multiple monitoring segments, the present invention can accurately locate the joint position where partial discharge occurs. By comparing the difference between the expected current and the measured current, partial discharge problems can be discovered in a timely manner, realizing the early warning function of the power cable, and improving the safety and reliability of the power system. The present invention is applicable to various power cable joint partial discharge monitoring scenarios, especially for deep-sea or deeply buried cable joint monitoring such as submarine power cables and large-scale 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, the target power cable is divided into multiple monitoring sections based on the starting point, end point and joints of the target power cable, including:

[0076] determining a temperature change section of the target power cable based on an installation environment of the target power cable;

[0077] Along the direction from the starting point to the end point of the target power cable, the starting point, end point and each joint contained in the target power cable are included in each temperature change segment to obtain multiple monitoring segments, so that the starting point of the first monitoring segment is the starting point of the target power cable, the end point of the last monitoring segment is the end point of the target power cable, and the starting points and end points of the other monitoring segments are the corresponding joints respectively.

[0078] Specifically, in practical applications, the installation environment of power cables can affect the cable's temperature distribution, thereby affecting the current transmission characteristics. Therefore, when dividing monitoring segments, it is necessary to consider the impact of the cable's installation environment on temperature. For example, if the cable is partially laid underground and partially above ground, the temperatures in the underground and above-ground sections may differ significantly, necessitating the division of monitoring segments 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 current collected by the sensor at the starting point of the monitoring segment in the initial stage after the target power cable is laid is used as the first starting point current, and the current collected by the sensor at the end point of the monitoring segment in the initial stage after the target power cable is laid is used as the first end point current. The reference temperature is determined based on the sensor collected temperatures at each preset position and each joint of the monitoring segment in the initial stage after the target power cable is laid.

[0081] Specifically, in the initial phase 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. Simultaneously, temperature sensors are installed at various preset locations and joints in the monitoring segment to obtain the temperature values at each point. The baseline temperature is then calculated by averaging or weighted averaging these temperature values.

[0082] In an optional embodiment of the present 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, and is implemented by the following formula:

[0083]

[0084] Wherein, α0 is the reference current attenuation coefficient, L is the cable length of the monitoring section, I s,1 is the first starting current, I d,1 is the first endpoint current.

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

[0086] The sensor collected current at the starting point of the monitoring node during the operation phase after the target power cable is laid is used as the second starting point current, and 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 normal operation of the power cable, a current sensor is installed at the starting point of the monitoring segment to obtain the current value at the second starting point. Simultaneously, temperature sensors are installed at various preset locations and joints in the monitoring segment to obtain the temperature value at each point. The measured temperature is then calculated by averaging or weighted averaging these temperature values.

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

[0089]

[0090] Wherein, α(T) is the actual current attenuation coefficient, T0 is the reference temperature, T is the measured temperature, and β is the conductor resistance temperature coefficient of the target power cable material;

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

[0092]

[0093] Among them, I k (T) is the expected current of the kth joint of the monitoring segment, I s,2 is the second starting current, x k is the cable length from the kth connector of the monitoring segment to the starting point of the monitoring segment.

[0094] In an optional embodiment of the present invention, determining, for each joint, a partial discharge condition corresponding to the joint based on the measured current and the expected current of the joint, 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, includes:

[0095] For each joint, if the difference between the expected current and the measured current of the joint is not less than a preset threshold, it is determined that partial discharge exists in the joint;

[0096] If the number of joints with partial discharge among the 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 given a partial discharge warning.

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

[0098] Similarly, the preset number 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 number can be set to 2. If partial discharge is detected at two or more joints, a partial discharge warning is required for the entire power cable.

[0099] Figure 2 An embodiment of the present invention provides a cable joint partial discharge monitoring system, 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, end point and joints of the target power cable, and determine the monitoring segment to which each joint belongs;

[0101] The reference current attenuation coefficient acquisition module 202 is configured to acquire, for each monitoring segment, a first starting point current, a first end point current, and a reference temperature of the monitoring segment in an initial stage after the target power cable is laid, and determine the reference current attenuation coefficient of the monitoring segment based on the first starting point current, the first end point current, and the cable length of the monitoring segment;

[0102] The expected current acquisition module 203 is used to obtain the second starting point current and the measured temperature of the monitoring segment during the operation phase after the target power cable is laid, and 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 determine the expected current corresponding to each joint included in the monitoring segment based on the second starting point 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 configured to determine, for each joint, a partial discharge condition corresponding to the joint based on the measured current and the expected current of the joint, and to determine 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.

[0104] The solution provided by this application is to divide the power cable into multiple monitoring segments, obtain a baseline current attenuation coefficient in the initial stage, consider the impact of temperature changes on current attenuation during the operation stage, calculate the actual current attenuation coefficient, and accurately predict the expected current of each joint. By comparing the difference between the expected current and the measured current, the partial discharge of the power cable joint can be accurately monitored, thereby improving the monitoring accuracy. By considering the impact of temperature changes on current attenuation, the present invention eliminates the interference caused by ambient temperature changes, making the monitoring results more reliable, and is particularly suitable for situations where the temperature of the cable laying environment varies greatly. By dividing the cable into multiple monitoring segments, the present invention can accurately locate the joint position where partial discharge occurs. By comparing the difference between the expected current and the measured current, partial discharge problems can be discovered in a timely manner, realizing the early warning function of the power cable, and improving the safety and reliability of the power system. The present invention is applicable to various power cable joint partial discharge monitoring scenarios, especially for deep-sea or deeply buried cable joint monitoring such as submarine power cables and large-scale 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, the target power cable is divided into multiple monitoring sections based on the starting point, end point and joints of the target power cable, including:

[0106] determining a temperature change section of the target power cable based on an installation environment of the target power cable;

[0107] Along the direction from the starting point to the end point of the target power cable, the starting point, end point and each joint contained in the target power cable are included in each temperature change segment to obtain multiple monitoring segments, so that the starting point of the first monitoring segment is the starting point of the target power cable, the end point of the last monitoring segment is the end point of the target power cable, and the starting points and end points of the other monitoring segments are the corresponding joints respectively.

[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 current collected by the sensor at the starting point of the monitoring segment in the initial stage after the target power cable is laid is used as the first starting point current, and the current collected by the sensor at the end point of the monitoring segment in the initial stage after the target power cable is laid is used as the first end point current. The reference temperature is determined based on the sensor collected temperatures at each preset position and each joint of the monitoring segment in 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 end current, and the cable length of the monitoring segment, and is implemented by the following formula:

[0111]

[0112] Wherein, α0 is the reference current attenuation coefficient, L is the cable length of the monitoring section, I s,1 is the first starting current, I d,1 is the first endpoint current.

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

[0114] The sensor collected current at the starting point of the monitoring node during the operation phase after the target power cable is laid is used as the second starting point current, and 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 actual current attenuation coefficient of the monitoring segment is determined based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, and is implemented by the following formula:

[0116]

[0117] Wherein, α(T) is the actual current attenuation coefficient, T0 is the reference temperature, T is the measured temperature, and β is the conductor resistance temperature coefficient of the target power cable material;

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

[0119]

[0120] Among them, I k(T) is the expected current of the kth joint of the monitoring segment, I s,2 is the second starting current, x k is the cable length from the kth connector of the monitoring segment to the starting point of the monitoring segment.

[0121] In an optional embodiment of the present invention, determining, for each joint, a partial discharge condition corresponding to the joint based on the measured current and the expected current of the joint, 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, includes:

[0122] For each joint, if the difference between the expected current and the measured current of the joint is not less than a preset threshold, it is determined that partial discharge exists in the joint;

[0123] If the number of joints with partial discharge among the 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 given a partial discharge warning.

[0124] Figure 3 An example of a physical structure diagram of an electronic device is shown below. Figure 3As shown, the electronic device may include: a processor (processor) 310, a communication interface (Communications Interface) 320, a memory (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 the logic instructions in the memory 330 to execute the power cable joint partial discharge monitoring method, the method comprising: dividing the target power cable into a plurality of monitoring segments based on the starting point, the end point and the joints contained in the target power cable, 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, obtaining the first starting point current, the first end point 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 point current, the first end point current and the cable length of the monitoring segment; in the operation stage after the target power cable is laid, obtaining the first starting point current, the first end point current and the reference temperature of the monitoring segment; The second starting point current and the measured temperature of the monitoring segment are measured, 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; and then based on the second starting point current, the actual current attenuation coefficient and the cable length from each connector included in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each connector included in the monitoring segment is determined; for each connector, the local discharge situation corresponding to the connector is determined based on the measured current and the expected current of the connector, and the local discharge situation corresponding to the target power cable is determined based on the local discharge situation corresponding to each connector included in the target power cable.

[0125] In addition, the logic instructions in the above-mentioned memory 330 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0126] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the power cable joint partial discharge monitoring method provided by the above methods, the method comprising: dividing the target power cable into multiple monitoring segments based on the starting point, end point and joints contained in the target power cable, 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, obtaining the first starting point current, the first end point current and the reference temperature of the monitoring segment, and determining the monitoring segment based on the first starting point current, the first end point current and the cable length of the monitoring segment. The reference current attenuation coefficient of the segment; in the operation stage after the target power cable is laid, the second starting point current and the 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, and then based on the second starting point current, the actual current attenuation coefficient and the cable length from each joint contained in the monitoring segment to the starting point of the monitoring segment, the expected current corresponding to each joint contained in the monitoring segment is determined; for each joint, the local discharge situation corresponding to the joint is determined based on the measured current and the expected current of the joint, and based on the local discharge situation corresponding to each joint contained in the target power cable, the local discharge situation corresponding to the target power cable is determined.

[0127] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the power cable joint partial discharge monitoring method provided by the above-mentioned methods, the method comprising: dividing the target power cable into a plurality of monitoring segments based on the starting point, the end point and the 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, obtaining the first starting point current, the first end point 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 point current, the first end point current and the cable length of the monitoring segment; in the During the operation phase after the target power cable is laid, the second starting point current and the 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, and then based on the second starting point 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, the local discharge situation corresponding to the joint is determined based on the measured current and the expected current of the joint, and based on the local discharge situation corresponding to each joint included in the target power cable, the local discharge situation 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, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0129] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain 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, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for monitoring partial discharge of a power cable joint, characterized in that: The method comprises: Divide the target power cable into multiple monitoring segments based on the starting point, end point, and joints of the target power cable, and determine the monitoring segment to which each joint belongs; For each monitoring segment, in an initial stage after the target power cable is laid, obtaining a first starting point current, a first end point 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 point current, the first end point current, and the cable length of the monitoring segment; During the operation phase after the target power cable is laid, obtaining the second starting point current and the measured temperature of the monitoring segment, and determining the actual current attenuation coefficient of the monitoring segment based on the measured temperature, the reference temperature, and the reference current attenuation coefficient; and further determining the expected current corresponding to each joint included in the monitoring segment based on the second starting point 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; For each joint, the partial discharge condition corresponding to the joint is determined based on the measured current and the expected current of the joint, and the partial discharge condition corresponding to the target power cable is determined based on the partial discharge conditions corresponding to each joint included in the target power cable.

2. The method according to claim 1, characterized in that The target power cable is divided into multiple monitoring sections based on the starting point, end point and joints of the target power cable, including: determining a temperature change section of the target power cable based on an installation environment of the target power cable; Along the direction from the starting point to the end point of the target power cable, the starting point, end point and each joint contained in the target power cable are included in each temperature change segment to obtain multiple monitoring segments, so that the starting point of the first monitoring segment is the starting point of the target power cable, the end point of the last monitoring segment is the end point of the target power cable, and the starting points and end points of the other monitoring segments are the corresponding joints respectively.

3. The method according to claim 1, characterized in that The obtaining of the first starting point current, the first end point current and the reference temperature of the monitoring segment includes: The current collected by the sensor at the starting point of the monitoring segment in the initial stage after the target power cable is laid is used as the first starting point current, and the current collected by the sensor at the end point of the monitoring segment in the initial stage after the target power cable is laid is used as the first end point current. The reference temperature is determined based on the sensor collected temperatures at each preset position and each joint of the monitoring segment in the initial stage after the target power cable is laid.

4. The method according to claim 1, wherein Based on the first starting current, the first ending current, and the cable length of the monitoring segment, a reference current attenuation coefficient of the monitoring segment is determined, which is achieved by the following formula: Wherein, α0 is the reference current attenuation coefficient, L is the cable length of the monitoring section, I s,1 is the first starting current, I d,1 is the first endpoint current.

5. The method according to claim 1, wherein The obtaining of the second starting point current and the measured temperature of the monitoring segment includes: The sensor collected current at the starting point of the monitoring node during the operation phase after the target power cable is laid is used as the second starting point current, and 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.

6. The method according to claim 1, characterized in that The actual current attenuation coefficient of the monitoring segment is determined based on the measured temperature, the reference temperature, and the reference current attenuation coefficient, and is implemented by the following formula: Wherein, α(T) is the actual current attenuation coefficient, T0 is the reference temperature, T is the measured temperature, and β is the conductor resistance temperature coefficient of the target power cable material; The expected current corresponding to each connector included in the monitoring segment is determined based on the second starting point current, the actual current attenuation coefficient, and the cable length from each connector included in the monitoring segment to the starting point of the monitoring segment, and is achieved by the following formula: Among them, I k (T) is the expected current of the kth joint of the monitoring segment, I s,2 is the second starting current, x k is the cable length from the kth connector of the monitoring segment to the starting point of the monitoring segment.

7. The method according to claim 1, characterized in that The determining, for each joint, a partial discharge condition corresponding to the joint based on the measured current and the expected current of the joint, 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, includes: For each joint, if the difference between the expected current and the measured current of the joint is not less than a preset threshold, it is determined that partial discharge exists in the joint; If the number of joints with partial discharge among the 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 given a partial discharge warning.

8. A power cable joint partial discharge monitoring system, characterized in that: The system comprises: A monitoring segment acquisition module is used to divide the target power cable into multiple monitoring segments based on the starting point, end point and joints of the target power cable, and determine the monitoring segment to which each joint belongs; a reference current attenuation coefficient acquisition module, configured to acquire, for each monitoring segment, a first starting point current, a first end point current, and a reference temperature of the monitoring segment in an initial stage after the target power cable is laid, and determine the reference current attenuation coefficient of the monitoring segment based on the first starting point current, the first end point current, and the cable length of the monitoring segment; an expected current acquisition module, configured to obtain, during the operation phase after the target power cable is laid, the second starting point current and the measured temperature of the monitoring segment, 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 further determine the expected current corresponding to each joint included in the monitoring segment based on the second starting point 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; a partial discharge condition determination module for determining, for each joint, a partial discharge condition corresponding to the joint based on the 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.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images