Method and device for processing relay protection parameters of power distribution network based on cable fault model

Abstract

The embodiment of the invention provides a processing method and equipment for relay protection parameters of a power distribution network based on a cable fault model. The method comprises the following steps: acquiring test data of an intermediate joint of a cable in a power distribution network in an arc breakdown test; determining values of model parameters of the cable fault model according to the test data; according to the value of each model parameter and the cable fault model, a simulation model is constructed; wherein the cable fault model is obtained by fitting the fault data of the intermediate joint of the cable according to the high-resistance grounding fault state of the intermediate joint of the cable; and performing simulation processing based on the simulation model, and determining relay protection parameters of the power distribution network. The method is used for accurately determining relay protection parameters of the relay protection system in the power distribution network. Based on the relay protection system configured with the relay protection parameters, the current in the high-resistance grounding fault state is accurately identified, so that relay protection is triggered, and the operation safety and reliability of the power distribution network are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution network, and particularly relates to a processing method and device of a protection parameter of a power distribution network based on a cable fault model. BACKGROUND

[0002] In order to reliably supply power to users in a power distribution network system, a relay protection system is provided. Based on the protection parameter of the relay protection system, the relay protection can be triggered when a cable in the power distribution network system fails, thereby ensuring the operation safety of the power distribution network.

[0003] In some technologies, the protection parameter of the relay protection system in the power distribution network system is set by manual experience. In the above technology, the relay protection system cannot accurately identify the high-resistance grounding fault state of the power distribution network, and cannot trigger the relay protection in this state, so the operation safety of the power distribution network is low.

[0004] Therefore, there is an urgent need for a scheme for accurately determining the protection parameter of the relay protection system, so that the relay protection system configured with the protection parameter can accurately identify the high-resistance grounding fault state. SUMMARY

[0005] The processing method and device of the protection parameter of the power distribution network based on the cable fault model provided by the embodiments of the present application are used to accurately determine the protection parameter of the relay protection system in the power distribution network; based on the relay protection system configured with the protection parameter, the current in the high-resistance grounding fault state is accurately identified, thereby triggering the relay protection, and improving the operation safety and reliability of the power distribution network.

[0006] In a first aspect, the embodiments of the present application provide a processing method of a protection parameter of a power distribution network based on a cable fault model, comprising:

[0007] Collecting test data of a middle joint of a cable in an arc breakdown test in a power distribution network; wherein the test data includes current waveform data and voltage waveform data;

[0008] According to the test data, the values of the model parameters of the cable fault model are determined; and according to the values of the model parameters and the cable fault model, a simulation model is constructed; wherein the cable fault model is fitted according to the fault data of the middle joint of the cable in the high-resistance grounding fault state.

[0009] Based on the simulation model, simulation processing is performed to determine the protection parameter of the power distribution network; wherein the protection parameter is the parameter of the relay protection system in the power distribution network, and the protection parameter includes the setting value and the setting time of the relay protection system.

[0010] In a possible implementation, the cable fault model comprises a first stage sub-model and a second stage sub-model; wherein the first stage sub-model represents a rising stage of the arc conductance of the intermediate joint, and the second stage sub-model represents a falling stage of the arc conductance of the intermediate joint.

[0011] The first stage sub-model in the cable fault model is obtained by fitting a sinusoidal curve function according to fault data when the intermediate joint of the cable is in the rising stage.

[0012] The second stage sub-model in the cable fault model is obtained by fitting a cosine curve function according to fault data when the intermediate joint of the cable is in the falling stage.

[0013] In a possible implementation, the model parameters of the cable fault model comprise: an amplitude of the arc conductance change rate, an arc breakdown starting time, an arc maintenance time, and a rising proportion value; wherein the rising proportion value is a proportion of the duration of the rising stage of the arc conductance to the arc maintenance time.

[0014] In a possible implementation, the values of the model parameters of the cable fault model are determined according to the test data, comprising:

[0015] The value of the amplitude of the arc conductance change rate is determined according to the test data based on a preset calculation formula.

[0016] The arc conductance waveform data is determined according to the test data; wherein the arc conductance waveform data is obtained by dividing the current waveform data by the voltage waveform data.

[0017] The voltage waveform and the arc conductance waveform are plotted according to the voltage waveform data and the arc conductance waveform data in the test data; and the values of the arc breakdown starting time, the arc maintenance time, and the duration of the rising stage of the arc conductance are determined according to the voltage waveform and the arc conductance waveform.

[0018] The rising proportion value is determined as a proportion between the value of the duration of the rising stage of the arc conductance and the value of the arc maintenance time.

[0019] In a possible implementation, the values of the model parameters of the cable fault model are determined according to the test data, comprising:

[0020] The operating stage of the cable fault model is determined according to the test data; and the value range of the model parameter corresponding to the operating stage is determined according to the operating stage.

[0021] The value of the model parameter of the cable fault model is determined according to the value range of the model parameter; wherein the value belongs to the value range.

[0022] In a possible implementation, based on the simulation model, the simulation processing is performed to determine the relay protection parameter of the power distribution network, including:

[0023] Based on the simulation model, the simulation processing is performed in the high-resistance grounding fault state to obtain a plurality of first monitoring data in the high-resistance grounding fault state.

[0024] According to the minimum value in the plurality of first monitoring data and the maximum value in a plurality of second monitoring data, a setting value in the relay protection parameter of the power distribution network is determined; wherein the plurality of second monitoring data are data monitored in a normal state of the intermediate joint of the cable; the setting value is greater than the maximum value in the plurality of second monitoring data and less than the minimum value in the plurality of first monitoring data.

[0025] According to the plurality of first monitoring data in the high-resistance grounding fault state, a transient duration is determined; and based on the transient duration, a setting time in the relay protection parameter of the power distribution network is determined.

[0026] The setting time is greater than or equal to the transient duration; the transient duration represents a duration from a starting time to an ending time; the starting time is a time when the simulation model starts the simulation processing in the high-resistance grounding fault state; the ending time is a time when the simulation model enters a steady-state fault state; the steady-state fault state represents that the first monitoring data is greater than or equal to the setting value, and a duration that the first monitoring data is greater than or equal to the setting value is greater than a preset time threshold.

[0027] In a second aspect, an embodiment of the present application provides a processing device for a relay protection parameter of a power distribution network based on a cable fault model, including:

[0028] The acquisition module is configured to acquire test data of the intermediate joint of the cable in the arc breakdown test in the power distribution network; wherein the test data includes current waveform data and voltage waveform data.

[0029] The processing module is configured to determine values of model parameters of the cable fault model according to the test data, and construct a simulation model according to the values of the model parameters and the cable fault model; wherein the cable fault model is fitted according to fault data of the power distribution network in a high-resistance grounding fault state of the intermediate joint of the cable.

[0030] The processing module is further configured to perform simulation processing based on the simulation model to determine the relay protection parameter of the power distribution network; wherein the relay protection parameter is a parameter of a relay protection system in the power distribution network, and the relay protection parameter includes a setting value and a setting time of the relay protection system.

[0031] In a possible implementation, the cable fault model comprises a first stage sub-model and a second stage sub-model; wherein the first stage sub-model represents a rising stage of the arc conductance of the intermediate joint, and the second stage sub-model represents a falling stage of the arc conductance of the intermediate joint.

[0032] The first stage sub-model in the cable fault model is fitted based on a sinusoidal curve function according to fault data when the intermediate joint of the cable is in the rising stage.

[0033] The second stage sub-model in the cable fault model is fitted based on a cosine curve function according to fault data when the intermediate joint of the cable is in the falling stage.

[0034] In a possible implementation, the model parameters of the cable fault model comprise: an amplitude of the arc conductance change rate, an arc breakdown starting time, an arc maintenance time, and a rising proportion value; wherein the rising proportion value is a ratio of the duration of the rising stage of the arc conductance to the arc maintenance time.

[0035] In a possible implementation, the model parameters of the cable fault model are determined according to the test data, and the processing module is configured to:

[0036] determine the amplitude of the arc conductance change rate according to the test data based on a preset calculation formula;

[0037] determine arc conductance waveform data according to the test data; wherein the arc conductance waveform data is obtained by dividing current waveform data by voltage waveform data;

[0038] draw a voltage waveform and an arc conductance waveform according to the voltage waveform data and the arc conductance waveform data in the test data; and determine the arc breakdown starting time, the arc maintenance time, and the duration of the rising stage of the arc conductance according to the voltage waveform and the arc conductance waveform.

[0039] determine the rising proportion value as a ratio between the duration of the rising stage of the arc conductance and the arc maintenance time.

[0040] In a possible implementation, the model parameters of the cable fault model are determined according to the test data, and the processing module is configured to:

[0041] determine a running stage of the cable fault model according to the test data; and determine a value range of a model parameter corresponding to the running stage according to the running stage;

[0042] determine the model parameter of the cable fault model according to the value range of the model parameter; wherein the value is within the value range.

[0043] In a possible implementation, based on the simulation model, the simulation processing is performed to determine the relay protection parameter of the power distribution network, and the processing module is configured to:

[0044] Based on the simulation model, the simulation processing is performed in the high-resistance grounding fault state to obtain a plurality of first monitoring data in the high-resistance grounding fault state.

[0045] According to the minimum value in the plurality of first monitoring data and the maximum value in a plurality of second monitoring data, a setting value in the relay protection parameter of the power distribution network is determined, wherein the plurality of second monitoring data are data monitored in a normal state of the intermediate joint of the cable; the setting value is greater than the maximum value in the plurality of second monitoring data and less than the minimum value in the plurality of first monitoring data.

[0046] According to the plurality of first monitoring data in the high-resistance grounding fault state, a transient duration is determined; and based on the transient duration, a setting time in the relay protection parameter of the power distribution network is determined.

[0047] The setting time is greater than or equal to the transient duration; the transient duration represents a duration from a starting time to an ending time, the starting time is a time when the simulation model starts the simulation processing in the high-resistance grounding fault state, and the ending time is a time when the simulation model enters a steady-state fault state, the steady-state fault state represents that the first monitoring data is greater than or equal to the setting value, and a duration that the first monitoring data is greater than or equal to the setting value is greater than a preset time threshold.

[0048] In a third aspect, an embodiment of the present application provides an electronic device, comprising: a memory and a processor.

[0049] The memory stores computer execution instructions.

[0050] The processor executes the computer execution instructions stored in the memory, so that the processor executes the first aspect and / or various possible implementation manners of the first aspect.

[0051] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, the computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by the processor to implement the first aspect and / or various possible implementation manners of the first aspect.

[0052] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising a computer program, the computer program is executed by the processor to implement the first aspect and / or various possible implementation manners of the first aspect.

[0053] The embodiment provided by the application provides a processing method and device of a power distribution network relay protection parameter based on a cable fault model, wherein the value of the parameter of the cable fault model is determined according to the test data of the power distribution network in an arc breakdown test; wherein the cable fault model is fitted according to the fault data obtained under a high-resistance grounding fault state of the power distribution network; a simulation model is determined based on the cable fault model and the value of each parameter; and the simulation processing is performed based on the simulation model to determine the relay protection parameter, i.e. the setting value and the setting time, of the relay protection system of the power distribution network. The relay protection parameter of the power distribution network can be accurately determined, so that the relay protection system of the power distribution network can accurately and timely identify the high-resistance grounding fault state of the intermediate joint of the cable and act to protect the safe operation of the power distribution network. BRIEF DESCRIPTION OF DRAWINGS

[0054] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0055] Figure 1 The flowchart of the processing method of the power distribution network relay protection parameter based on the cable fault model provided by the application Figure 1

[0056] Figure 2 The schematic diagram of an exemplary cable fault model

[0057] Figure 3 The flowchart of the processing method of the power distribution network relay protection parameter based on the cable fault model provided by the application Figure 2

[0058] Figure 4 The schematic diagram of an exemplary voltage waveform and arc conductance waveform

[0059] Figure 5 The flowchart of the processing method of the power distribution network relay protection parameter based on the cable fault model provided by the application Figure 3

[0060] Figure 6 The flowchart of the processing method of the power distribution network relay protection parameter based on the cable fault model provided by the application Figure 4

[0061] Figure 7 The schematic diagram of an exemplary simulation model

[0062] Figure 8 The structural schematic diagram of the processing device of the power distribution network relay protection parameter based on the cable fault model provided by the application

[0063] Figure 9 The structural schematic diagram of the electronic device provided by the application​​​​

[0064] The specific embodiments of the application have been shown by way of example in the above figures, and will be described in more detail below. These figures and this written description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept by reference to specific embodiments. DETAILED DESCRIPTION

[0065] Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, same or like reference numbers have been used in different drawings to indicate the same or similar elements. The embodiments described in the following examples do not represent all of the implementations consistent with the present application. Instead, they are merely examples consistent with some aspects of the present application as detailed in the appended claims.

[0066] Firstly, the terms involved in the present application are explained:

[0067] Arcing breakdown test: refers to the phenomenon that when the electric field strength applied to the insulating material exceeds its critical value, its insulating performance suddenly loses, and it changes from an insulator to a conductor. In the present application, the arcing breakdown test is carried out on the intermediate joint of the power distribution network cable.

[0068] Intermediate joint of the cable: refers to a special connecting device used to connect two cables of the same type, which makes them electrically conductive, mechanically protected, and restores the original insulation level.

[0069] High resistance grounding fault state: refers to the current generated by the breakdown discharge of the cross-linked polyethylene-silicone rubber insulation interface (XLPE-SiR interface for short) inside the intermediate joint of the cable in the early or middle stage of the fault, which is too low (usually less than 10A), which reflects the high resistance grounding fault, and cannot trigger the trip threshold of the relay protection system. If this fault state is not identified and the relay protection operation is performed, it may cause the fault of the intermediate joint of the cable to further expand and cause an accident.

[0070] Relay protection parameters: refer to the relay protection parameters of the relay protection system in the power distribution network, including the setting value and the setting time. Among them, the setting value refers to the parameter value set in advance by the protection relay or circuit breaker in the relay protection system. The parameter value can be current, voltage or temperature. When the measured physical quantity reaches or exceeds this parameter value, the device will perform the relay protection action; the setting time refers to the delay action time set in advance by the protection relay or circuit breaker in the relay protection system. From the time when the condition is met, the device will perform the relay protection action after this time period.

[0071] The power distribution network system can realize reliable power supply to users. In the power distribution network system, a relay protection system is usually arranged. Based on the relay protection parameters of the relay protection system, the relay protection can be triggered when a fault occurs in the power distribution network system, thereby ensuring the safe operation of the power distribution network.

[0072] In the power distribution network system, power is transmitted through cables, and the cables are connected through intermediate joints. The XLPE-SiR interface is present in the intermediate joint of the cable, and when the XLPE-SiR interface is subjected to arc breakdown, a high-resistance grounding fault state is present.

[0073] In some embodiments, the relay protection parameters of the relay protection system in the power distribution network system are usually set manually based on experience. However, when the intermediate joint of the cable is in a high-resistance grounding fault state, the actual value of the discharge current is low, and cannot reach the setting value of the relay protection parameters set manually. This causes the relay protection system to fail to identify the high-resistance grounding fault state of the intermediate joint of the cable, and the relay protection cannot be triggered in this state. If the intermediate joint of the cable develops in the high-resistance grounding fault state, more serious fault phenomena will occur, which poses a safety risk, and the safe operation of the power distribution network is low.

[0074] In combination with the above embodiments, it can be seen that the relay protection parameters of the power distribution network relay system are set manually based on experience, which cannot identify the high-resistance grounding fault state of the intermediate joint of the cable, and causes the safe operation of the power distribution network to be low.

[0075] The processing method for the relay protection parameters of the power distribution network based on the cable fault model provided in the present application determines the values of the parameters of the cable fault model according to the test data of the power distribution network in the arc breakdown test; wherein the cable fault model is fitted according to the fault data obtained when the power distribution network is in a high-resistance grounding fault state; based on the cable fault model and the values of the parameters, a simulation model is determined; based on the simulation model, simulation processing is performed to determine the relay protection parameters, i.e. the setting value and the setting time, of the relay protection system of the power distribution network, which solves the technical problem of being unable to identify the high-resistance grounding fault state of the intermediate joint of the cable, thereby improving the safe operation of the power distribution network.

[0076] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail in the following specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0077] Figure 1 The flowchart of the processing method for the relay protection parameters of the power distribution network based on the cable fault model provided in the present application Figure 1 As Figure 1As shown, the method comprises:

[0078] Step 101. Collecting test data of the intermediate joint of the cable in the power distribution network in the arc breakdown test.

[0079] The test data comprises current waveform data and voltage waveform data.

[0080] For example, the arc breakdown test is performed on the intermediate joint of the cable in the power distribution network, and during the arc breakdown test, the test data of the power distribution network in the arc breakdown test is collected by a smart meter or other measuring device.

[0081] The test data comprises voltage data and current data of the intermediate joint. The voltage data and the current data are sequences varying with time; therefore, the voltage data and the current data at different time can be used as the current waveform data and the voltage waveform data.

[0082] Step 102. Determining the value of the model parameter of the cable fault model according to the test data; and constructing a simulation model according to the value of each model parameter and the cable fault model.

[0083] The cable fault model is fitted according to the fault data of the intermediate joint of the cable in the high-resistance grounding fault state.

[0084] For example, the cable fault model comprises at least one model parameter, the value of each model parameter can be determined according to the test data, and the value of each model parameter is substituted into the cable fault model to construct the simulation model.

[0085] For example, the fault data of the discharge channel of the intermediate joint of the fault cable is collected when the intermediate joint of the cable is in the high-resistance grounding fault state, such as the fault voltage and the fault current. The cable fault model is derived according to the fault voltage and the fault current. The construction process of the specific cable fault model can be referred to the examples below.

[0086] Optionally, the value of the model parameter of the cable fault model is determined according to the current waveform data and the voltage waveform data in the test data based on a preset calculation formula. The arc conductance can also be determined according to the current waveform data and the voltage waveform data, and the value of the model parameter of the cable fault type is determined based on the curve of the arc conductance.

[0087] Optionally, the operating phase is determined according to the test data based on the value range of the model parameter corresponding to different operating phases of the intermediate joint of the cable; and the value of the model parameter is determined according to the value range corresponding to the operating phase.

[0088] Step 103. Performing simulation processing based on the simulation model to determine the relay protection parameter of the power distribution network.

[0089] The relay protection parameter is a parameter of a relay protection system in the power distribution network, and the relay protection parameter includes a setting value and a setting time of the relay protection system.

[0090] For example, the simulation processing is performed based on the simulation model. Specifically, the simulation processing is performed based on the simulation model when the middle joint of the cable is in the normal state and in the high-resistance grounding fault state, respectively. The relay protection parameter of the relay protection system of the power distribution network is determined according to the monitoring data when the middle joint of the cable is in the normal state and in the high-resistance grounding fault state. The relay protection parameter includes the setting value and the setting time.

[0091] It can be understood that the setting value can accurately identify whether the middle joint of the cable is in the normal state or in the high-resistance grounding fault state. In addition, because the monitoring data of the power distribution network is in shock in the high-resistance grounding fault state, the setting time can avoid the false triggering of the relay protection system caused by the shock, and ensure that the relay protection system is triggered when the middle joint of the cable of the power distribution network is in the high-resistance grounding fault state.

[0092] The processing method for the relay protection parameter of the power distribution network based on the cable fault model provided by the embodiments of the present application can obtain the cable fault model by fitting when the middle joint of the cable is in the high-resistance grounding fault state, and can determine the value of the model parameter of the cable fault model based on the test data collected when the power distribution network is subjected to the arc breakdown test, and can obtain the simulation model by constructing. The simulation processing is performed based on the simulation model, so as to determine the more accurate setting value and setting time. The relay protection system of the power distribution network is configured based on the determined setting value and setting time, so that the relay protection system can accurately identify the high-resistance grounding fault state of the middle joint of the cable, and can be triggered to protect the normal and safe operation of the power distribution network, and to improve the operation safety and reliability of the power distribution network.

[0093] In the foregoing embodiments, the cable fault model is obtained by fitting the data when the middle joint of the cable is in the high-resistance grounding fault state.

[0094] For example, the fault data is obtained when the middle joint of the cable is in the high-resistance grounding fault state. The fault data can include the current fault waveform and the voltage fault waveform.

[0095] The current fault curve and the voltage fault curve can be drawn according to the current fault waveform and the voltage fault waveform.

[0096] According to the data of each data point in the current fault curve, the data of the corresponding data point in the voltage fault curve is divided to obtain the arc conductance corresponding to different data points. The fitting curve of the arc conductance is obtained by fitting the arc conductance corresponding to different data points.

[0097] The fitting curve of the arc conductance is differentiated to obtain a fitting curve of the first derivative of the arc conductance.

[0098] In an example, the cable fault model includes a first stage sub-model and a second stage sub-model; wherein the first stage sub-model represents a rising stage of the arc conductance of the intermediate joint, and the second stage sub-model represents a falling stage of the arc conductance of the intermediate joint.

[0099] Figure 2 A schematic diagram of an example cable fault model. As shown in Figure 2 , in Figure 2 , the green curve is the arc conductance corresponding to the different data points; the red dot-dashed line is the fitting curve of the arc conductance; and the blue dashed line is the fitting curve of the first derivative of the arc conductance.

[0100] Figure 2 The fitting curve of the first derivative of the arc conductance in the rising region of the conductance, i.e., the curve corresponding to the first stage sub-model. It should be noted that, in combination with the red dot-dashed line in the rising region of the conductance, it can be seen that the red dot-dashed line is increasing in this stage. Therefore, this stage is the rising stage of the arc conductance of the intermediate joint of the cable.

[0101] Figure 2 The fitting curve of the first derivative of the arc conductance in the falling region of the conductance, i.e., the curve corresponding to the second stage sub-model. It should be noted that, in combination with the red dot-dashed line in the falling region of the conductance, it can be seen that the red dot-dashed line is decreasing in this stage. Therefore, this stage is the falling stage of the arc conductance of the intermediate joint of the cable.

[0102] Further, in order to avoid the problem of too many fitting coefficients and not clear enough physical parameter representation caused by using high-order functions for fitting, the fitting curve of the first derivative of the arc conductance is abstracted into an expression using cosine curve and sine curve approximation method.

[0103] Specifically, the first stage sub-model in the cable fault model is obtained by fitting based on a sine curve function according to the fault data of the intermediate joint of the cable in the rising stage.

[0104] Specifically, the second stage sub-model in the cable fault model is obtained by fitting based on a cosine curve function according to the fault data of the intermediate joint of the cable in the falling stage.

[0105] For example, the cable fault model can be represented by the following formula (1):

[0106] (1)

[0107] In formula (1), represents the arc conductance in the discharge channel of the cable joint; represents the amplitude of the rate of change of the conductance in the conductance rising region, in mS / ms; represents the amplitude of the rate of change of the conductance in the conductance falling region, in mS / ms; represents the arc breakdown initiation time compared to the zero-crossing point of the power frequency voltage (voltage waveform data in the test data), in ms; represents the arc breakdown maintenance time, in ms; represents the proportion of the conductance rising region. Wherein, represents different times.

[0108] In combination with formula (1), at , the corresponding expression is the expression of the first sub-model. The expression of the first sub-model is fitted based on a sine curve function. In this time interval, it belongs to the rising phase of the arc conductance of the joint.

[0109] In combination with formula (1), at , the corresponding expression is the expression of the second sub-model. The expression of the second sub-model is fitted based on a cosine curve function. In this time interval, it belongs to the falling phase of the arc conductance of the joint.

[0110] In combination with formula (1) in the foregoing examples, it can be seen that the cable fault model includes a plurality of model parameters.

[0111] In an example, the model parameters of the cable fault model include: the amplitude of the arc conductance rate of change, the arc breakdown initiation time, the arc maintenance time, and the rising proportion value.

[0112] The rising proportion value is the ratio of the duration of the rising phase of the arc conductance to the arc maintenance time.

[0113] The amplitude of the arc conductance rate of change, i.e. and in the foregoing examples and formula (1); the arc breakdown initiation time, i.e. in the foregoing examples and formula (1); the arc maintenance time, i.e. in the foregoing examples and formula (1); and the rising proportion value, i.e. in the foregoing examples and formula (1).

[0114] The in the amplitude of the arc conductance rate of change refers to the amplitude of the first derivative (arc conductance rate of change) of the corresponding arc conductance in the rising phase of the arc conductance; and the​​ is referred to as the amplitude of the first derivative of the arc conductance (arc conductance change rate) corresponding to the descending phase of the arc conductance.

[0115] Arc breakdown starting time is referred to as the time interval between the time when the voltage waveform data (power frequency voltage) crosses zero and the time when the arc starts to break down.

[0116] Arc maintenance time is referred to as the time interval between the starting time of the arc breakdown and the ending time of the arc breakdown.

[0117] Rise ratio value is referred to as the ratio between the duration of the rising phase of the arc conductance and the arc maintenance time.

[0118] In the above examples, the cable fault model is fitted by using relatively simple sine curve functions and cosine curve functions. Therefore, the total number of parameters is reduced; and the physical meaning of each model parameter is more explicit.

[0119] On this basis, the values of the model parameters can be calculated directly according to the preset calculation formula combined with the test data. Alternatively, the current operating phase of the intermediate joint of the cable can be determined according to the test data; and the value of the model parameter can be determined within the recommended value range of the model parameter according to the value range of the model parameter recommended for different operating phases.

[0120] Figure 3 Flowchart of the processing method of the relay protection parameter of the power distribution network based on the cable fault model provided in the present application Figure 2 In an example, as shown in Figure 3 , the process of determining the value of the model parameter can include the following steps:

[0121] Step 301. Determine the value of the amplitude of the arc conductance change rate based on the preset calculation formula according to the test data.

[0122] For example, the preset calculation formula can refer to the following formula (2) and formula (3), wherein formula (2) is the amplitude of the arc conductance change rate corresponding to the rising phase of the arc conductance, and formula (3) is the amplitude of the arc conductance change rate corresponding to the descending phase of the arc conductance:

[0123] (2)

[0124] (3)

[0125] In the above formula (2) and formula (3), Arc channel current waveform data collected in the arc breakdown test; Arc channel voltage waveform data collected in the arc breakdown test.

[0126] Step 302. Determine arc conductance waveform data according to the test data.

[0127] Wherein, the arc conductance waveform data is obtained by dividing the current waveform data by the voltage waveform data.

[0128] For example, the test data includes current waveform data and voltage waveform data. The current waveform data is divided by the voltage waveform data, and the arc conductance waveform data is obtained.

[0129] Step 303. Draw the voltage waveform and the arc conductance waveform according to the voltage waveform data and the arc conductance waveform data in the test data; and determine the value of the arc breakdown initiation time, the value of the arc maintenance time and the duration of the rising phase of the arc conductance according to the voltage waveform and the arc conductance waveform.

[0130] For example, the voltage waveform and the arc conductance waveform are drawn according to the voltage waveform data and the arc conductance waveform data. Figure 4 The figure is a schematic diagram of the example voltage waveform and the arc conductance waveform. As shown in Figure 4 The red solid line marked by the red solid line is the voltage waveform drawn according to the voltage waveform data; the blue solid line marked by the blue solid line is the arc conductance waveform drawn according to the arc conductance waveform data.

[0131] In combination with Figure 4 Analysis, on the blue solid line, the arc conductance waveform is divided into the rising phase and the falling phase of the arc conductance by the blue dashed line.

[0132] In combination with Figure 4 Analysis, at the intersection of the red solid line and the coordinate axis, that is, the zero-crossing point of the power frequency voltage. Based on the zero-crossing point of the power frequency voltage, the time interval between the start time of the arc breakdown (the starting point of the arc conductance waveform) Figure 4 , is the arc breakdown initiation time. The value of the arc breakdown initiation time can be read by the value on the coordinate axis.

[0133] In combination with Figure 4 Analysis, the time interval represented between the two intersection points of the blue solid line and the coordinate axis is the arc maintenance time. The value of the arc maintenance time can be read by the value on the coordinate axis.

[0134] In combination with Figure 4 Analysis, in the blue solid line, the rising phase and the falling phase of the arc conductance divided by the blue dashed line can be read by the coordinate axis to obtain the duration of the rising phase of the arc conductance.

[0135] It should be noted that the blue dashed line is used to divide the rising phase and the falling phase of the arc conductance. Therefore, at the position of the blue dashed line, the arc conductance changes from the rising phase to the falling phase. The time point corresponding to the derivative value of 0 can be obtained by taking the derivative of the arc conductance, that is, taking the derivative of the arc conductance and setting the derivative value to 0. On the left and right sides of the time point, the first derivative of the arc conductance changes from positive to negative. On the image, it is embodied that on the left and right sides of the time point, the waveform of the arc conductance changes from an increasing trend to a decreasing trend. It can be understood that the position corresponding to the time point is the position corresponding to the blue dashed line.

[0136] Step 304. Determine the ratio value between the duration of the rising phase of the arc conductance and the value of the arc maintenance time as the value of the rising ratio.

[0137] For example, the duration of the rising phase of the arc conductance determined in the foregoing step 303 is divided by the arc maintenance time to obtain the value of the rising ratio.

[0138] In combination with Figure 4 the explanation of the Figure 4 annotated in the foregoing step 303, the duration of the rising phase of the arc conductance is obtained.

[0139] In the above example, the user can self-determine the parameters according to the actual test data, improve the flexibility and accuracy of the cable fault model, and adapt to complex and variable fault scenarios.

[0140] Figure 5 The flowchart of the processing method of the relay protection parameter of the power distribution network based on the cable fault model provided in the present application Figure 3 In an example, as shown in the foregoing step 501, the process of determining the value of the model parameter can include the following steps: Figure 5

[0141] Step 501. According to the test data, determine the running phase of the cable fault model; and according to the running phase, determine the value range of the model parameter corresponding to the running phase.

[0142] For example, the running phase of the cable fault model can include: a starting phase, an intermediate phase, a first transition phase (also referred to as transition phase 1), a second transition phase (also referred to as transition phase 2), and a late phase.

[0143] ​​For example, the stage of the cable fault model can be determined according to the test data. The test data can include, but is not limited to, arc voltage, arc current, breakdown time, initial conductance, effective value of arc current, conductance stability, time constant, current change rate, conductance change direction, arc energy, current zero-crossing point, conductance minimum value, reignition voltage, residual conductance, extinction time, etc.

[0144] For example, the judgment condition of the initial stage can include one or more of the following judgment conditions: 1. The arc voltage suddenly drops from the high voltage of the insulation state to the arc initiation voltage; 2. The arc current quickly rises from 0 but the amplitude is small; 3. The arc conductance (calculated according to the arc current divided by the arc voltage) starts to steeply increase from close to 0.

[0145] For example, the judgment condition of the middle stage can include one or more of the following judgment conditions: 1. The effective value of the arc current tends to be stable; 2. The arc voltage is stable at a low level; 3. The arc conductance has small fluctuations.

[0146] For example, the judgment condition of the first transition stage can include one or more of the following judgment conditions: 1. The arc current appears to attenuate or change rapidly; 2. The current change rate is negative, and the arc conductance decreases with the decrease of the current; 3. The arc energy (calculated by integrating the product of the arc current and the arc voltage) slows down or starts to decrease.

[0147] For example, the judgment condition of the second transition stage can include one or more of the following judgment conditions: 1. The arc current approaches or passes through the zero point, and the arc conductance decreases to below the minimum threshold; 2. The arc voltage rises, but is less than the system voltage; 3. The arc voltage reaches the reignition voltage.

[0148] For example, the judgment condition of the late stage can include one or more of the following judgment conditions: 1. The arc conductance continuously decreases to close to 0; 2. The arc voltage rises to the system voltage; 3. The arc current continuously is 0.

[0149] Further, after determining the operating stage of the intermediate joint of the cable, the value range of the model parameter is determined according to the operating stage.

[0150] Specifically, the value range of the model parameter corresponding to different operating stages can refer to Table 1 as follows.

[0151] Table 1 Value range table of model parameters of operating stage

[0152]

[0153] In combination with Table 1, the value range of each model parameter is determined according to the operating stage of the cable fault model.

[0154] Step 502. Determine the values ​​of the model parameters for the cable fault model based on the range of values ​​for the model parameters.

[0155] The values ​​are within the range of possible values.

[0156] For example, in conjunction with the aforementioned steps, the value range of each model parameter is determined, and within this value range, a value is selected as the value of that model parameter.

[0157] In the above example, the operating stage of the cable's intermediate joint was determined using experimental data. Determining the fault parameter values ​​for the cable fault model based on the operating stage allows the model to adapt to the fault characteristics of different operating stages, improving the accuracy and applicability of the cable fault model in identifying different operating stages under high-resistance grounding fault conditions.

[0158] Figure 6 A flowchart illustrating the method for processing relay protection parameters of distribution networks based on cable fault models provided in this application. Figure 4 In one example, such as Figure 6 As shown, the process of determining the relay protection parameters of a distribution network may include the following steps:

[0159] Step 601. Based on the simulation model, perform simulation processing under the high-resistance grounding fault state to obtain multiple first monitoring data under the high-resistance grounding fault state.

[0160] For example, as illustrated in the preceding examples, the model parameters from the cable fault model are substituted into the cable fault model itself. A simulation model is then constructed based on the expression of the cable fault model. This simulation model, through modular design, simulates the changes in electrical quantities and protection logic detection of the cable's intermediate joint under a high-resistance grounding fault condition.

[0161] Figure 7 This is a schematic diagram of an exemplary simulation model. Figure 7 As shown in [a], the end labeled "in" is the input port of the simulation model, and the end labeled "out" is the output port of the simulation model; the "rDaxi" labeled in the middle is... Figure 7 The output of the model shown in [b] represents the diffusion resistance, the reciprocal of which is the arc conductance. Figure 7 [b] refers to the cable fault model in the aforementioned example. For example... Figure 7 As shown in [b], the cable fault model has multiple model parameter inputs, such as... Figure 7The symbols “A1”, “A2”, “t0”, “Ta”, and “B” marked in [b] correspond to the amplitude of the arc conductance change rate during the rising phase, the amplitude of the arc conductance change rate during the falling phase, the arc breakdown initiation time, the arc sustaining time, and the rise ratio, respectively, of the model parameters in the aforementioned example. Substituting the values ​​of each model parameter into the cable fault model allows for simulation processing.

[0162] Combination Figure 7 To explain [b], the cable fault model includes a delay module, control switch module 1, and control switch module 2. The delay module simulates the delay characteristics of a high-resistance grounding fault, or the delay phase of a protection action. Control switch module 1 switches between the rising and falling phases of the arc conductance. Specifically, when control switch module 1 is in position A, it indicates the rising phase of the arc conductance; when it is in position B, it indicates the falling phase of the arc conductance. Control switch module 2 switches between the ignition and extinguishing states of the arc. Specifically, when control switch module 2 is in position A, it indicates an arc at the cable's intermediate joint; when it is in position B, it indicates the arc at the cable's intermediate joint is extinguished. Furthermore, when the arc at the cable's intermediate joint is extinguished, the arc conductance is extremely high, with an exemplary value of 1 million ohms.

[0163] It should be noted that, in Figure 7 In [b], the remaining part is the electrical quantity calculation module, including the multiplication module, the division module, and the trigonometric function module. Through the above modules, a cable fault model with the same calculation logic as formula (1) can be constructed.

[0164] in, Figure 7 In [a], the input port is used to input basic electrical quantities of the system, such as the normal operating voltage or current signal of the power system where the cable is located; the output port is used to output quantities based on the input basic electrical quantities of the system. Figure 8 The "rDaxi" obtained from [b] is used for calculation and simulation to obtain the first monitoring data. For example, the current signal output by the intermediate joint of the cable under high-resistance ground fault conditions.

[0165] Step 602. Determine the setting value in the relay protection parameters of the distribution network based on the minimum value among multiple first monitoring data and the maximum value among multiple second monitoring data.

[0166] Among them, multiple second monitoring data are data obtained by monitoring the intermediate joint of the cable under normal conditions; the setting value is greater than the maximum value among multiple second monitoring data and less than the minimum value among multiple first monitoring data.

[0167] Exemplarily, during the simulation processing, one monitoring data can be obtained at each time. It can be understood that during the time period of the simulation processing, multiple first monitoring data can be obtained, and the minimum value of the multiple first monitoring data can be determined.

[0168] Exemplarily, before the simulation processing, simulation processing in the normal state can be performed, that is, the monitoring data of the intermediate joint of the cable in the normal state, that is, multiple second monitoring data, can be obtained. It should be noted that the multiple second monitoring data can also be recorded according to actual application. Further, according to the multiple second monitoring data, the maximum value of the multiple second monitoring data can be determined.

[0169] For example, the first monitoring data is the current data of the intermediate joint of the cable in the high-resistance grounding fault state, and the second monitoring data is the current data of the intermediate joint of the cable in the normal state.

[0170] In order to enable the relay protection system of the power distribution network to distinguish between the normal state and the high-resistance grounding fault state, the setting value needs to be between the monitoring data in the normal state and the monitoring data in the high-resistance grounding fault state.

[0171] Generally, taking the current data as an example of the monitoring data, the first monitoring data in the high-resistance grounding fault state is generally higher than the second monitoring data in the normal state. Therefore, the setting value is set to be greater than the maximum value of the second monitoring data and less than the minimum value of the first monitoring data. That is, the setting value is greater than the maximum value of the normal state and less than the minimum value of the fault. Thus, the normal state and the high-resistance grounding fault state can be accurately distinguished.

[0172] Optionally, in a possible case, when the minimum value of the multiple first monitoring data is less than or equal to the maximum value of the multiple second monitoring data, the minimum value of the first monitoring data is selected as the setting value. Although this may cause the monitoring data in the normal state to be misjudged as a fault, all monitoring data in the high-resistance grounding fault state can be identified, ensuring safety.

[0173] Step 603. According to the multiple first monitoring data in the high-resistance grounding fault state, the transient duration is determined, and the setting time of the relay protection parameter of the power distribution network is determined based on the transient duration.

[0174] The setting time is greater than or equal to the transient duration; the transient duration represents a duration from a starting time to an ending time, the starting time is a time when the simulation model starts simulation processing in the high-resistance grounding fault state, and the ending time is a time when the simulation model enters a steady-state fault state, the steady-state fault state represents that the first monitoring data is greater than or equal to the setting value, and a duration that the first monitoring data is greater than or equal to the setting value is greater than a preset time threshold.

[0175] For example, the starting time is a time when the simulation model starts simulation in the high-resistance grounding fault state; the simulation processing is continuously performed, and the ending time is a time when the simulation model enters the steady-state fault state. The time interval between the starting time and the ending time is recorded as the transient duration.

[0176] The transient duration represents an early stage of the simulation model in the high-resistance grounding fault state. The first monitoring data may exceed the setting value temporarily due to transient oscillation and then fall back. It can be understood that the transient oscillation is not a characteristic of the real high-resistance grounding fault state. If the protection action of the relay system is performed at this time, the reliability is reduced.

[0177] Therefore, the setting time needs to avoid the duration of the transient disturbance, and ensures that the protection action of the relay system is performed when the first monitoring data is stable and continuously exceeds the setting value (that is, the simulation model enters the steady-state fault state of the high-resistance grounding fault state).

[0178] Optionally, the condition for determining that the steady-state fault state is entered can be that the first monitoring data is greater than or equal to the setting value, and a duration that the first monitoring data is greater than or equal to the setting value is greater than a preset time threshold. The preset time threshold can be set according to experience or manually preset.

[0179] Optionally, the condition for determining that the steady-state fault state is entered can be that a fluctuation amplitude of the first monitoring data is less than or equal to a preset fluctuation amplitude threshold. The fluctuation amplitude threshold can be set according to experience or manually preset.

[0180] For example, the setting time is greater than or equal to the transient duration. It should be noted that the setting time cannot be much greater than the transient duration. The setting time can be obtained on the basis of the transient duration and based on a preset delay time.

[0181] In the above example, the simulation model is constructed by the cable fault model and the corresponding model parameters; the simulation processing is respectively performed under the normal state and the high-resistance grounding fault state based on the simulation model. The setting value is determined based on the measurement value under the normal state and the measurement value under the high-resistance grounding fault state; the setting time is determined based on the time when the simulation model enters the stable high-resistance grounding fault state. The dynamic simulation of the whole process of the arc breakdown initiation, maintenance and extinction of the intermediate joint of the cable can be realized by the simulation model, and the authenticity of the high-resistance grounding fault state simulation is improved. On this basis, the setting value and the setting time determined can be close to the real high-resistance grounding fault state, so that in actual application, the relay protection system of the power distribution network can accurately identify the high-resistance grounding fault state of the intermediate joint of the cable.

[0182] The processing method for the relay protection parameters of the power distribution network based on the cable fault model provided in the embodiments of the present application can fit the cable fault model when the intermediate joint of the cable is in the high-resistance grounding fault state, and determine the values of the model parameters of the cable fault model based on the test data collected when the power distribution network is subjected to the arc breakdown test, so as to construct the simulation model; the simulation processing is performed based on the simulation model, so as to determine more accurate setting value and setting time. The relay protection system of the power distribution network is configured based on the determined setting value and setting time, so that the relay protection system can accurately identify the high-resistance grounding fault state of the intermediate joint of the cable, so as to act, realize the normal and safe operation of the power distribution network, and improve the operation safety and reliability of the power distribution network.

[0183] The sine and cosine curve functions are used to fit the curve, so as to reduce the total number of the model parameters of the cable fault model, and the physical meaning of each model parameter is clear.

[0184] The calculation of the values of the model parameters by the pre-designed calculation formula based on the test data, or the determination of the operation stage of the intermediate joint of the cable based on the test data and the determination of the values from the value range of the corresponding model parameters corresponding to the corresponding operation stage can improve the flexibility and practical applicability of the cable fault model.

[0185] The simulation under the normal state and the high-resistance grounding fault state is performed based on the simulation model, and the relay protection parameters are determined based on the simulation monitoring data under the two states. The accuracy of the relay protection parameters is improved.

[0186] Figure 8 The structure diagram of the processing device for the relay protection parameters of the power distribution network based on the cable fault model provided in the present application is shown in Figure 9 The processing device 80 for the relay protection parameters of the power distribution network based on the cable fault model provided in the embodiments of the present application includes:

[0187] The collection module 801 collects test data of the intermediate joint of the cable in the power distribution network in an arc breakdown test, wherein the test data includes current waveform data and voltage waveform data.

[0188] The processing module 802 is configured to determine values of model parameters of a cable fault model according to the test data, and construct a simulation model according to the values of the model parameters and the cable fault model, wherein the cable fault model is fitted according to fault data of the power distribution network when the intermediate joint of the cable is in a high-resistance grounding fault state.

[0189] The processing module 802 is further configured to perform simulation processing based on the simulation model to determine a relay protection parameter of the power distribution network, wherein the relay protection parameter is a parameter of a relay protection system in the power distribution network, and the relay protection parameter includes a setting value and a setting time of the relay protection system.

[0190] In a possible implementation, the cable fault model includes a first-stage sub-model and a second-stage sub-model, wherein the first-stage sub-model represents a rising stage of arc conductance of the intermediate joint, and the second-stage sub-model represents a falling stage of the arc conductance of the intermediate joint.

[0191] The first-stage sub-model in the cable fault model is fitted based on a sinusoidal curve function according to fault data when the intermediate joint of the cable is in the rising stage.

[0192] The second-stage sub-model in the cable fault model is fitted based on a cosine curve function according to fault data when the intermediate joint of the cable is in the falling stage.

[0193] In a possible implementation, the model parameters of the cable fault model include an amplitude of an arc conductance change rate, an arc breakdown starting time, an arc maintenance time, and a rising proportion value, wherein the rising proportion value is a ratio of a duration of the rising stage of the arc conductance to the arc maintenance time.

[0194] In a possible implementation, the processing module 802 is configured to determine the values of the model parameters of the cable fault model according to the test data in the following manner.

[0195] The processing module 802 is configured to determine the value of the amplitude of the arc conductance change rate according to the test data based on a preset calculation formula.

[0196] The processing module 802 is configured to determine arc conductance waveform data according to the test data, wherein the arc conductance waveform data is obtained by dividing the current waveform data by the voltage waveform data.

[0197] According to the voltage waveform data and the arc conductance waveform data in the test data, voltage waveforms and arc conductance waveforms are drawn; and according to the voltage waveforms and the arc conductance waveforms, the value of the arc breakdown starting time, the value of the arc maintaining time and the duration of the rising phase of the arc conductance are determined.

[0198] The ratio value between the duration of the rising phase of the arc conductance and the value of the arc maintaining time is determined as the value of the rising ratio.

[0199] In a possible implementation, according to the test data, the value of the model parameter of the cable fault model is determined, and the processing module 802 is configured to:

[0200] According to the test data, the operation phase of the cable fault model is determined; and according to the operation phase, the value range of the model parameter corresponding to the operation phase is determined.

[0201] According to the value range of the model parameter, the value of the model parameter of the cable fault model is determined; wherein the value belongs to the value range.

[0202] In a possible implementation, based on the simulation model, simulation processing is performed to determine the relay protection parameter of the power distribution network, and the processing module 802 is configured to:

[0203] Based on the simulation model, simulation processing is performed under the high-resistance grounding fault state to obtain a plurality of first monitoring data under the high-resistance grounding fault state.

[0204] According to the minimum value in the plurality of first monitoring data and the maximum value in a plurality of second monitoring data, the setting value in the relay protection parameter of the power distribution network is determined; wherein the plurality of second monitoring data are data monitored under the normal state of the intermediate joint of the cable; the setting value is greater than the maximum value in the plurality of second monitoring data and less than the minimum value in the plurality of first monitoring data.

[0205] According to the plurality of first monitoring data under the high-resistance grounding fault state, the transient duration is determined; and based on the transient duration, the setting time in the relay protection parameter of the power distribution network is determined.

[0206] The setting time is greater than or equal to the transient duration; the transient duration represents the duration from the starting time to the ending time, the starting time is the time when the simulation model starts simulation processing under the high-resistance grounding fault state, and the ending time is the time when the simulation model enters the steady-state fault state, the steady-state fault state represents that the first monitoring data is greater than or equal to the setting value, and the duration that the first monitoring data is greater than or equal to the setting value is greater than a preset time threshold.

[0207] The device for processing power distribution network relay protection parameters based on a cable fault model provided in this embodiment can execute the method provided in the method embodiments, and has similar implementation principles and technical effects, which will not be repeated here.

[0208] Figure 9 A structural schematic diagram of an electronic device provided in the present application is shown in FIG. 1. As shown in the figure, the electronic device 90 provided in this embodiment includes at least one processor 901 and a memory 902. Optionally, the electronic device 90 further includes a communication component 903. The processor 901, the memory 902 and the communication component 903 are connected through a bus 904. ​

[0209] In the specific implementation process, the at least one processor 901 executes the computer execution instructions stored in the memory 902, so that the at least one processor 901 executes the above-mentioned method.

[0210] The specific implementation process of the processor 901 can refer to the above-mentioned method embodiments, which has similar implementation principles and technical effects, which will not be repeated here.

[0211] In the above-mentioned embodiments, it should be understood that the processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC) and the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor and the like. The steps of the method disclosed in the present application can be directly embodied as the execution of the hardware processor, or executed by the combination of the hardware and software modules in the processor.

[0212] The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), for example, at least one disk memory.

[0213] ​The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of the present application does not limit to only one bus or one type of bus.

[0214] The present application also provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method described above.

[0215] The present application also provides a computer readable storage medium, which stores computer execution instructions, and when a processor executes the computer execution instructions, the method described above is implemented.

[0216] The readable storage medium described above can be implemented by any type of volatile or non-volatile storage device or their combination, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0217] An exemplary readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium, and can write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0218] The division of units is only a logical functional division, and in actual implementation, there can be another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0219] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e., may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0220] In addition, each functional unit in various embodiments of the application can be integrated into one processing unit, or each unit can exist physically, or two or more units can be integrated into one unit.

[0221] If the function is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the various embodiment methods of the application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0222] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The aforementioned program can be stored in a computer readable storage medium. The program executes to perform the steps of the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, and various program code storage media.

[0223] Finally, it should be noted that those skilled in the art, after considering the specification and practicing the application disclosed herein, will easily think of other embodiments of the application. The application is intended to cover any variations, uses, or adaptations of the application that follow the general principles of the application and include common knowledge or conventional techniques in the art that are not disclosed by the application, and is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the application is only limited by the appended claims.

Claims

1. A method for processing relay protection parameters of a distribution network based on a cable fault model, characterized in that, include: Collect test data of intermediate joints of cables in the power distribution network during arc breakdown tests; wherein, the test data includes: current waveform data and voltage waveform data; Based on the experimental data, the values ​​of the model parameters of the cable fault model are determined; and based on the values ​​of each model parameter and the cable fault model, a simulation model is constructed; wherein, the cable fault model is obtained by fitting the fault data of the cable joint under a high-resistance grounding fault state. Based on the simulation model, simulation processing is performed to determine the relay protection parameters of the distribution network; wherein, the relay protection parameters are the parameters of the relay protection system in the distribution network, and the relay protection parameters include: the setting value and setting time of the relay protection system.

2. The method according to claim 1, characterized in that, The cable fault model includes a first-stage sub-model and a second-stage sub-model; wherein, the first-stage sub-model represents the rising stage of the arc conductance of the intermediate joint, and the second-stage sub-model represents the falling stage of the arc conductance of the intermediate joint. The first-stage sub-model in the cable fault model is obtained by fitting a sine curve function based on fault data of the cable's intermediate joint during the rising stage. The second-stage sub-model in the cable fault model is obtained by fitting a cosine curve function based on fault data of the cable's intermediate joint during the descent phase.

3. The method according to claim 1, characterized in that, The model parameters of the cable fault model include: the amplitude of the arc conductivity change rate, the arc breakdown initiation time, the arc sustaining time, and the rise ratio; wherein, the rise ratio is the ratio of the duration of the arc conductivity rise phase to the arc sustaining time.

4. The method according to claim 3, characterized in that, Based on the test data, the values ​​of the model parameters for the cable fault model are determined, including: Based on the preset calculation formula, the value of the amplitude of the arc conductivity change rate is determined according to the test data; Based on the test data, the arc conductance waveform data is determined; wherein, the arc conductance waveform data is obtained by dividing the current waveform data by the voltage waveform data; Based on the voltage waveform data and the arc conductance waveform data in the test data, plot the voltage waveform and the arc conductance waveform; and based on the voltage waveform and the arc conductance waveform, determine the value of the arc breakdown initiation time, the value of the arc sustaining time, and the duration of the rising phase of the arc conductance. The ratio between the duration of the rising phase of the arc conductivity and the arc sustaining time is determined as the value of the rising ratio.

5. The method according to claim 3, characterized in that, Based on the test data, the values ​​of the model parameters for the cable fault model are determined, including: Based on the test data, the operating stage of the cable fault model is determined; and based on the operating stage, the value range of the model parameters corresponding to the operating stage is determined. The values ​​of the model parameters for the cable fault model are determined based on the range of values ​​of the model parameters; wherein the values ​​fall within the range of values.

6. The method according to any one of claims 1-5, characterized in that, Based on the simulation model, simulation processing is performed to determine the relay protection parameters of the distribution network, including: Based on the simulation model, simulation processing is performed under a high-resistance grounding fault state to obtain multiple first monitoring data under the high-resistance grounding fault state. The setting value in the relay protection parameters of the distribution network is determined based on the minimum value among the plurality of first monitoring data and the maximum value among the plurality of second monitoring data; wherein, the plurality of second monitoring data are data obtained by monitoring the intermediate joint of the cable under normal conditions; the setting value is greater than the maximum value among the plurality of second monitoring data and less than the minimum value among the plurality of first monitoring data; Based on multiple first monitoring data under the high-resistance grounding fault state, the transient duration is determined; and based on the transient duration, the setting time in the relay protection parameters of the distribution network is determined. Wherein, the setting time is greater than or equal to the transient duration; the transient duration represents the duration from the start time to the end time, the start time is the moment when the simulation model starts simulation processing in a high-resistance ground fault state, the end time is the moment when the simulation model enters a steady-state fault state, and the steady-state fault state represents that the first monitoring data is greater than or equal to the setting value, and the duration for which the first monitoring data is greater than or equal to the setting value is greater than a preset time threshold.

7. A device for processing relay protection parameters of a distribution network based on a cable fault model, characterized in that, include: The data acquisition module is used to acquire test data of intermediate joints of cables in the power distribution network during arc breakdown tests; wherein, the test data includes: current waveform data and voltage waveform data; The processing module is used to determine the values ​​of the model parameters of the cable fault model based on the test data; and to construct a simulation model based on the values ​​of each model parameter and the cable fault model; wherein the cable fault model is obtained by fitting the fault data of the distribution network based on the intermediate joint of the cable under the high resistance grounding fault state. The processing module is further configured to perform simulation processing based on the simulation model to determine the relay protection parameters of the distribution network; wherein the relay protection parameters are the parameters of the relay protection system in the distribution network, and the relay protection parameters include: the setting value and setting time of the relay protection system.

8. An electronic device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method of any one of claims 1-6.

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