Single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method

Abstract

The application discloses a single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method, and belongs to the technical field of power system protection and control, and comprises the following steps: S1, setting a single neutral point small resistance grounding active distribution network high resistance grounding fault direction discrimination criterion; S2, setting a single neutral point small resistance grounding active distribution network high resistance grounding fault area fault criterion; S3, setting a single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method action flow; and S4, calculating the maximum allowable measurement error boundary. The single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method can guarantee the reliability of line switch fault direction judgment of the single neutral point small resistance grounding active distribution network single-phase high resistance grounding fault, and effectively identifies the high resistance grounding fault section.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system protection and control, in particular to a single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method. BACKGROUND

[0002] In the prior art, in recent years, with the development of social economy and the continuous expansion of urban scale, the number of cable access is rapidly increasing, and the capacitive current of distribution network is increasing. Small resistance grounding method has been gradually promoted and applied in distribution network. However, the setting value of the commonly used time-limit zero sequence overcurrent protection is generally 40-60A, and the maximum can only detect single-phase grounding fault with transition resistance of about 85-135Ω. When high resistance grounding fault occurs, the protection will refuse to act. For the distribution network using cables, the line capacitive current is large. Limited by the maximum system capacitive current to ground, the time-limit zero sequence overcurrent protection setting value is large, and the transition resistance detection capability is small. And the cable line is generally buried underground, when the cable insulation is aging or damaged, single-phase grounding fault will occur, the transition resistance is high, the fault current is weak, and it is difficult to identify and troubleshoot. For the distribution network using overhead lines, single-phase grounding fault may occur due to conductor falling, natural factors, human body contact, etc. The transition resistance can be as high as several hundred to several thousand ohms, although the capacitive current to ground is small, but there is still a problem of high tripping rate and high resistance fault protection implementation. Therefore, how to realize the rapid detection of single-phase high resistance grounding fault and accurately isolate the neutral point small resistance grounding system has important significance for the safe and stable operation and application development.

[0003] With the proposal of the "double carbon" target, the penetration rate of distributed generators (DG) in distribution networks is continuously increasing. The single-phase grounding fault detection problem of the neutral point small resistance grounding distribution system with a high proportion of distributed generators has become the focus of attention in the industry. When DG grid-connected transformers use different grounding methods, the system equivalent zero sequence network structure after single-phase grounding fault has significant differences. In actual engineering research, due to the consideration of protection reliability and personal safety, DG grid-connected transformers in active distribution networks generally use ungrounded mode. The system using small resistance grounding mode and DG grid-connected transformers using ungrounded mode are defined as single neutral point small resistance grounding mode. Existing research on single-phase high resistance grounding fault detection methods for small resistance grounding active distribution networks often focuses on the identification of fault feeders and non-fault feeders, and there is less research on single neutral point small resistance grounding mode. With the increasing demand for fault location of distribution networks, the existing detection method that only identifies single-phase high resistance grounding fault feeders will not meet the development needs of future new power systems, which is not conducive to the rapid positioning and processing of high resistance grounding of distribution networks.

[0004] Therefore, it is urgent to solve the problem of single-phase high-resistance grounding fault section of single neutral point small resistance grounding active distribution network, and meet the safe and reliable operation of single neutral point small resistance grounding active distribution network and the rapid processing requirement of high-resistance grounding fault. SUMMARY

[0005] The application aims to provide a single neutral point small resistance grounding active distribution network high-resistance grounding fault section identification method, which can ensure the reliability of line switch fault direction judgment of single neutral point small resistance grounding active distribution network in single-phase high-resistance grounding fault, and effectively identify the high-resistance grounding fault section.

[0006] To achieve the above-mentioned purpose, the application provides a single neutral point small resistance grounding active distribution network high-resistance grounding fault section identification method, which comprises the following steps:

[0007] S1, setting a single neutral point small resistance grounding active distribution network high-resistance grounding fault direction discrimination criterion;

[0008] S2, setting a single neutral point small resistance grounding active distribution network high-resistance grounding fault section identification method action flow;

[0009] S3, setting a single neutral point small resistance grounding active distribution network high-resistance grounding fault section identification method action flow;

[0010] S4, calculating the maximum allowable measurement error boundary.

[0011] Preferably, in S1, the following steps are specifically included:

[0012] S11, defining the symbols related to the fault direction discrimination criterion;

[0013] defining the zero sequence voltage amplitude at the switch as U (0) , the zero sequence current amplitude as I (0) , and the direction representation voltage as U (0) -6R n I (0) , and defining D as the fault direction;

[0014] S12, configuring the fault direction discrimination criterion based on the direction representation voltage.

[0015] Preferably, in S12, the following steps are specifically included:

[0016] S121, setting the small resistance value R n of the distribution network system grounding;

[0017] S122, the fault direction discrimination criterion based on the direction representation voltage is:

[0018]

[0019] When the positive direction fault occurs, the direction characteristic voltage is less than zero, and D is 1; when the reverse direction fault occurs, the direction characteristic voltage is greater than zero, and D is 0.

[0020] Preferably, S2 specifically comprises the following steps:

[0021] S21, classifying the switch types around the section, specifically comprising the following steps:

[0022] S211, defining the switch closest to the section bus switch as the upstream switch of the region, and defining D 上游 as the fault direction judgment result of the only switch upstream of the region;

[0023] S212, defining the switches other than the upstream switch of the region as the downstream switches of the region, and defining as the sum of the fault direction judgment results of all the downstream switches; S22, setting the fault criterion in the high-resistance grounding fault area.

[0024] Preferably, in S22, the fault criterion in the high-resistance grounding fault area is that the fault direction judgment result of the only switch upstream of the region is a positive direction fault, and the fault direction judgment results of all the downstream switches are reverse direction faults.

[0025]

[0026] Preferably, S3 specifically comprises the following steps:

[0027] S31, setting the starting criterion of the high-resistance grounding fault section identification method of the single neutral point small resistance grounding active power distribution network;

[0028] S32, setting the fault direction judgment flow of each switch after the high-resistance grounding fault of the single neutral point small resistance grounding active power distribution network;

[0029] S33, setting the high-resistance grounding fault section identification flow of the single neutral point small resistance grounding active power distribution network.

[0030] Preferably, S31 comprises the following steps:

[0031] S311, collecting zero sequence voltage and current for all switches, and starting the single-phase grounding fault section identification method when the zero sequence current difference sudden change variable of the zero sequence voltage and current of a certain switch meets the starting criterion;

[0032] S312, the zero sequence current difference sudden change variable starting criterion is:

[0033] ||i0(k)-i0(k-N)|-|i0(k-N)-i0(k-2N)||>ε;

[0034] In the formula, N is the number of sampling points per week of power frequency, i0(k) is the sampling value of zero sequence current, and ε is the threshold value of zero sequence current mutation starting criterion;

[0035] In S32, the following steps are included:

[0036] In S321, after the method is started, each switch collects steady-state measurement values, and the fault direction is judged according to the fault direction discrimination criterion set in S1.

[0037] In S322, each switch uploads the fault direction judgment result to the master station.

[0038] In S33, the following steps are included:

[0039] In S331, the master station collects the fault direction judgment results of the switches around the section to be discriminated.

[0040] In S332, the master station judges the fault section according to the high-resistance grounding fault-in-section criterion set in S2; if the section to be discriminated meets the set high-resistance grounding fault-in-section criterion, it is determined that a single-phase grounding fault occurs in the section; otherwise, the section is not faulty.

[0041] Preferably, in S4, the following steps are included:

[0042] In S41, the maximum allowable measurement error boundary of each switch at different transition resistances is calculated.

[0043] In S42, the maximum allowable measurement error boundary of the entire network at different transition resistances is calculated, and the measurement device precision is selected according to the maximum allowable measurement error boundary of the entire network at different transition resistances.

[0044] Preferably, in S41, the following steps are included:

[0045] In S411, the absolute value of the directional representation voltage at each switch when the edge endpoint of the distribution network fails at different transition resistances is obtained by one of the two methods of iterative calculation and simulation.

[0046] In S412, the minimum value of the absolute value of the directional representation voltage at the switch when all edge endpoints of the distribution network line fail is taken as the maximum allowable measurement error boundary of the switch, and the expression is as follows:

[0047] b = MIN |U (0) -6R n I (0) |;

[0048] In the formula, b is the maximum allowable measurement error boundary of the switch, MIN |U (0) -6R n I (0)| The absolute value of the directional representation voltage at the switch is the minimum value when all edge points of the distribution network are single-phase ground fault.

[0049] Preferably, in S42, the following steps are included:

[0050] S421, the minimum value of the maximum allowable measurement error boundary of all switches constituting the section identification method at different transition resistances is the maximum allowable measurement error boundary B of the whole network at different transition resistances;

[0051] S422, when the absolute error Δ u and the absolute error Δ i of the zero sequence current amplitude measured at all switches satisfy the following formula:

[0052] Δ u + 6R n Δ i <B;

[0053] , it indicates that the fault section identification is accurate.

[0054] S423, the maximum allowable measurement error boundary of the whole network at different transition resistances is different, and the measurement device selection is guided according to the maximum allowable measurement error at different sizes of transition resistance, that is, the measurement accuracy of the required measurement device is determined according to the required resistance size.

[0055] Therefore, the beneficial effects of the single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method of the present application are:

[0056] (1) The method of the present application is aimed at the small resistance grounding active distribution network high resistance grounding fault section identification problem, and proposes a single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method based on directional representation voltage, and details the judgment interval range of switch fault direction and action criterion.

[0057] (2) The method of the present application is not affected by the size of the transition resistance and the arc discharge phenomenon when the high resistance grounding fault is accurately measured.

[0058] (3) The method of the present application considers the non-grounding mode of the distributed generator grid-connected transformer, and the reliability of the method is not affected by the DG access condition.

[0059] (4) The calculation principle of the fault direction judgment interval of the method of the present application is clear and easy to implement.

[0060] (5) The application proposes a maximum allowable measurement boundary method for the improved grounding fault section identification method, which provides two-way guidance for practical engineering application: determining the measurement equipment precision selection requirement based on the target transition resistance range; and evaluating the transition resistance tolerance ability of the proposed method in combination with the actual precision of the installed equipment.

[0061] The technical solutions of the application are further described below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is a typical single neutral point small resistance grounding active distribution network wiring schematic diagram;

[0063] Figure 2 is a flow chart of the single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method of the application. DETAILED DESCRIPTION

[0064] The technical solutions of the application are further described below with reference to the drawings and examples.

[0065] Unless otherwise defined, the technical terms or scientific terms used in the application should be understood as the usual meaning understood by a person with ordinary skills in the art to which the application belongs. The "first", "second" and similar words used in the application do not represent any order, quantity or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent the relative positional relationship, when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0066] Example 1

[0067] The application provides a single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method, which considers that the system adopts a small resistance grounding mode and the distributed power supply grid-connected transformer adopts a non-grounding mode, defines a direction representation voltage according to the difference in the upstream and downstream zero sequence current voltage characteristics of the fault point when a single-phase grounding fault occurs in the single neutral point small resistance grounding system, realizes single-phase grounding fault direction discrimination of the line switch through the positive and negative of the direction representation voltage, and identifies the fault in the section according to the criterion that the upstream switch of the section has a positive direction fault and the downstream switches all have a reverse direction fault. In the embodiment, the current positive direction of each protection device is as shown in the formula (1). Figure 1

[0068] ​The single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method of the embodiment specifically comprises the following steps.

[0069] S1, setting a single neutral point small resistance grounding active distribution network high resistance grounding fault direction discrimination criterion, comprising the following steps.

[0070] S11, defining symbols related to the fault direction discrimination criterion, specifically:

[0071] S111, defining the zero sequence voltage amplitude at the switch as U (0) , the zero sequence current amplitude as I (0) , and the direction representation voltage as U (0) -6R n I (0) .

[0072] S112, defining D as the fault direction, where D is 1 when the fault is in the positive direction, and D is 0 when the fault is in the reverse direction.

[0073] S12, configuring the fault direction discrimination criterion based on the direction representation voltage, specifically:

[0074] S121, setting the small resistance value R n of the distribution network system grounding as 10Ω.

[0075] S122, the fault direction discrimination criterion based on the direction representation voltage is:

[0076]

[0077] When the fault is in the positive direction, the direction representation voltage is less than zero, and D is 1; when the fault is in the reverse direction, the direction representation voltage is greater than zero, and D is 0.

[0078] S2, setting the single neutral point small resistance grounding active distribution network high resistance grounding fault section identification criterion, comprising the following steps:

[0079] S21, classifying the types of switches around the section, specifically:

[0080] S211, taking the bus outflow as the positive direction of current, defining the switch FSW1 closest to the system bus switch around the section as the upstream switch of the region, and defining D FSW1 as the fault direction judgment result of the only switch upstream of the region.

[0081] S212, defining the other switches FSW2, QSW1, QSW2 around the section except the upstream switch of the region as downstream switches of the region, and defining D FSW2 +D QSW1 +D QSW2 as the sum of the fault direction judgment results of all downstream switches.

[0082] S22, set high resistance grounding fault area fault criterion, specifically:

[0083] The upstream only switch fault direction judgment result is positive direction fault, and the downstream all switch fault direction judgment results are reverse direction fault, and the high resistance grounding fault area fault criterion is:

[0084]

[0085] S3, set the single neutral point small resistance grounding active power distribution network high resistance grounding fault section identification method action flow, as shown in Figure 2 , specifically comprising the following steps:

[0086] S31, set the single neutral point small resistance grounding active power distribution network high resistance grounding fault section identification method starting criterion, specifically:

[0087] S311, let all switches collect zero sequence voltage and current, when the zero sequence voltage and current of a switch meet the zero sequence current difference sudden change variable starting criterion, then start the single-phase grounding fault section identification method.

[0088] S312, the zero sequence current difference sudden change variable starting criterion is:

[0089] ||i0(k)-i0(k-N)|-|i0(k-N)-i0(k-2N)||>ε

[0090] In the formula, N is the sampling point number per week of power frequency, i0(k) is the zero sequence current sampling value, and ε is the zero sequence current sudden change variable starting criterion threshold.

[0091] S32, set the single neutral point small resistance grounding active power distribution network high resistance grounding fault after each switch fault direction judgment flow, specifically:

[0092] S321, after the method starts, each switch collects steady-state measurement value, and judges the fault direction according to the fault direction discrimination criterion set in S122.

[0093] S322, each switch uploads the fault direction judgment result to the master station.

[0094] S33, set the single neutral point small resistance grounding active power distribution network high resistance grounding fault section identification flow, specifically:

[0095] S331, the master station collects the fault direction judgment results of the switches around a section.

[0096] S332, the master station judges the fault section according to the high-resistance grounding fault area criterion set in S22, if a section meets the set high-resistance grounding fault area criterion, it is determined that a single-phase grounding fault occurs in the section; otherwise, the section is not faulty.

[0097] S4, calculating the maximum allowed measurement error boundary, specifically comprising the following steps:

[0098] S41, calculating the maximum allowed measurement error boundary of each switch at different transition resistances, specifically:

[0099] S411, obtaining the absolute value of the directional representation voltage at each switch when the edge endpoint of the distribution network fails at different transition resistances by one of the two methods of iterative calculation and simulation.

[0100] S412, taking the minimum value of the absolute value of the directional representation voltage at the switch when all edge endpoints of the distribution network line fail as the maximum allowed measurement error boundary of the switch.

[0101] b FSW1 = MIN |U (0) -6R n I (0) | FSW1.i

[0102] b FSW2 = MIN |U (0) -6R n I (0) | FSW2.i

[0103] b QSW1 = MIN |U (0) -6R n I (0) | QSW1.i

[0104] b QSW2 = MIN |U (0) -6R n I (0) | QSW2.i

[0105] i∈{k0,k5,k6,k7,k8}

[0106] In the formula, b FSW1 is the maximum allowed measurement error boundary of FSW1, b FSW2 is the maximum allowed measurement error boundary of FSW2, b QSW1 is the maximum allowed measurement error boundary of QSW1, b QSW2 is the maximum allowed measurement error boundary of QSW2, MIN |U (0) -6R nI (0) | FSW1.i MIN|U| is the minimum value of the absolute value of the directional characteristic voltage at FSW1 when all edge end points of the line are faulty (0) -6R n I (0) | FSW2.i MIN|U| is the minimum value of the absolute value of the directional characteristic voltage at FSW1 when all edge end points of the line are faulty (0) -6R n I (0) | QSW1.i MIN|U| is the minimum value of the absolute value of the directional characteristic voltage at FSW1 when all edge end points of the line are faulty (0) -6R n I (0) | QSW2.i MIN|U| is the minimum value of the absolute value of the directional characteristic voltage at FSW1 when all edge end points of the line are faulty, k0, k5, k6, k7, and k8 are all edge end points of the line

[0107] S42, calculate the maximum allowable measurement error boundary of the whole network when different transition resistances, and select the measurement device precision according to the maximum allowable measurement error boundary of the whole network when different transition resistances, specifically:

[0108] S421, the minimum value of the maximum allowable measurement error boundary of all switches constituting the section identification method when different transition resistances is the maximum allowable measurement error boundary B of the whole network when different transition resistances. Taking FSW1, FSW2, QSW1, and QSW2 as examples, the calculation formula of B is as follows:

[0109] B = MIN(b FSW1 ,b FSW2 ,b QSW1 ,b QSW2 )

[0110] S422, when the absolute error Δ u and the absolute error Δ i of the zero sequence voltage amplitude and the zero sequence current amplitude measured at all switches satisfy the following formula:

[0111] Δ u + 6R n Δ i < B

[0112] The method can guarantee the accuracy of fault section identification.

[0113] S423、different transition resistance, the maximum allowable measurement error boundary is different, according to the maximum allowable measurement error of different size transition resistance to guide the selection of measuring equipment, that is, according to the need to resist the size of the transition resistance to determine the required measurement equipment measurement accuracy. When the measurement equipment has been installed and the accuracy is known, the ability of the single-phase ground fault section identification method of the embodiment to resist the transition resistance can be determined according to the method of step S4.

[0114] Therefore, the present application adopts the above-mentioned single neutral point small resistance grounding active distribution network high resistance grounding fault section identification method, which can realize single neutral point small resistance grounding active distribution network high resistance grounding fault section identification, is not affected by the DG access condition, and is not affected by the size of the transition resistance and the arc discharge phenomenon during high resistance grounding fault under the condition that the electrical quantity can be accurately measured. Moreover, the maximum allowable measurement boundary method is proposed for the improved high resistance grounding fault section identification method, which provides two-way guidance for practical engineering application: determining the measurement equipment accuracy selection requirement based on the target transition resistance range. Combined with the actual accuracy of the installed equipment, the transition resistance resistance ability of the proposed method is evaluated.

[0115] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand: it can still modify or equivalently replace the technical solutions of the present application, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for identifying a high-resistance grounding fault section in a single neutral point low resistance grounding active distribution network, characterized in that, The method comprises the following steps: S1, setting a single neutral point small resistance grounding active power distribution network high resistance grounding fault direction discrimination criterion; S2, setting a single neutral point small resistance grounding active power distribution network high resistance grounding fault area fault criterion; S3, setting a single neutral point small resistance grounding active power distribution network high resistance grounding fault section identification method action flow; S4, calculating the maximum allowable measurement error boundary; In S1, the following steps are specifically included: S11, defining the fault direction discrimination criterion related symbol; Let the zero-sequence voltage amplitude at the switch be U (0) , the zero-sequence current amplitude be I (0) , and the directional representation voltage be U (0) -6R n I (0) , and let D be the fault direction. S12, configuring the fault direction discrimination criterion based on the direction characteristic voltage; In S12, the following steps are specifically included: S121, set the distribution network system grounding small resistance value R n ; S122, the fault direction discrimination criterion based on the direction characteristic voltage is: When the positive direction fault, the direction characteristic voltage is less than zero, and D is 1; when the reverse direction fault, the direction characteristic voltage is greater than zero, and D is 0; In S2, the following steps are specifically included: S21, classifying the section around switch type, specifically including the following steps: S211. Taking the outflow from the busbar as the positive direction of the current, the only switch in the vicinity of the section closest to the system busbar switch is defined as the upstream switch of the area, and D is defined. 上游 The result of determining the direction of the only switch fault upstream of the region; S212, define the other switches around the section except the upstream switch of the region as the downstream switches of the region, define the sum of the fault direction judgment results of all the downstream switches. S22, setting a high resistance grounding fault area fault criterion; In S22, the only switch upstream of the region is determined as the positive direction fault, and the downstream of all switches is determined as the reverse direction fault, which is the fault criterion in the region, and then the high resistance grounding fault area fault criterion is:

2. The single neutral point small resistance grounded active distribution network high resistance grounded fault section identification method of claim 1, wherein: In S3, the following steps are specifically included: S31, setting a single neutral point small resistance grounding active power distribution network high resistance grounding fault section identification method start criterion; S32, setting a single neutral point small resistance grounding active power distribution network high resistance grounding fault after each switch fault direction judgment flow; S33, setting a single neutral point small resistance grounding active power distribution network high resistance grounding fault section identification flow.

3. The single neutral point small resistance grounded active distribution network high resistance grounded fault section identification method of claim 2, wherein: In S31, the following steps are included: S311, let all switches collect zero sequence voltage and current, when the zero sequence voltage and current of a certain switch meet the zero sequence current difference mutation variable start criterion, then start the single-phase grounding fault section identification method; S312, the zero sequence current difference mutation variable start criterion is: ||i0(k)-i0(k-N)|-|i0(k-N)-i0(k-2N)||>ε; In the formula, N is the sampling point number per week of power frequency, i0(k) is the zero sequence current sampling value, and ε is the zero sequence current mutation variable start criterion threshold; In S32, the following steps are included: S321, after the method starts, each switch collects steady-state measurement value, and judges the fault direction according to the fault direction discrimination criterion set in S1; S322, each switch uploads the fault direction judgment result to the master station; In S33, the following steps are included: S331, the master station collects the switch fault direction judgment result around the section to be judged; S332, the master station judges the fault section according to the high resistance grounding fault area fault criterion set in S2; if the section to be judged meets the set high resistance grounding fault area fault criterion, it is determined that a single-phase grounding fault occurs in the section; otherwise, no fault occurs in the section.

4. The single neutral point small resistance grounded active distribution network high resistance grounded fault section identification method of claim 1, wherein: In S4, the following steps are specifically included: S41, calculating the maximum allowable measurement error boundary of each switch at different transition resistances; S42, calculate the maximum allowed measurement error boundary of the whole network at different transition resistances, and select the measurement device precision according to the maximum allowed measurement error boundary of the whole network at different transition resistances.

5. The single neutral point low resistance grounded active distribution network high resistance grounded fault section identification method of claim 4, wherein: S41 includes the following steps: S411, obtain the absolute value of the directional characteristic voltage at each switch when the edge endpoint of the distribution network fails at different transition resistances by one of the two methods of iterative calculation and simulation; S412, take the minimum value of the absolute value of the directional characteristic voltage at the switch when all edge endpoints of the distribution network line fail as the maximum allowed measurement error boundary of the switch, and the expression is as follows: b = MIN | U (0) -6R n I (0) |; where b is the maximum allowed measurement error margin of the switch, MIN|U (0) -6R n I (0) is the minimum value of the absolute value of the directional voltage at the switch when all edge points of the distribution network are single-phase earthed.

6. The single neutral point low resistance grounded active distribution network high resistance grounded fault section identification method of claim 4, wherein: S42 includes the following steps: S421, take the minimum value of the maximum allowed measurement error boundary of all switches constituting the section identification method at different transition resistances as the maximum allowed measurement error boundary of the whole network at different transition resistances B; S422、when all the switch measured zero sequence voltage amplitude absolute error Δ u and zero sequence current amplitude absolute error Δ i satisfy the following formula: Δ u +6R n Δ i <B; It indicates that the fault section identification is accurate; S423, the maximum allowed measurement error boundary of the whole network at different transition resistances is different, and the measurement device selection is guided according to the maximum allowed measurement error at different sizes of transition resistances, that is, the measurement accuracy of the required measurement device is determined according to the required resistance size.

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