CN114050564B - Power distribution network earth fault flexible regulation and control method considering network parameter influence - Google Patents
Power distribution network earth fault flexible regulation and control method considering network parameter influence Download PDFInfo
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Abstract
Accounting for network parametersThe method for flexibly regulating and controlling the grounding fault of the power distribution network comprises the following steps: (1) connecting the arc suppression converter to a neutral point of the power distribution network; (2) judging the fault condition of the power distribution network; (3) calculating fault phase load current
(4) Loading the fault phase with current
Real-time feedback quantity of circuit current relative to fault phase
Making a difference, and obtaining the residual voltage compensation quantity of the fault point through a first PI controller
(5) Compensating residual voltage of fault point
Negative value of power supply voltage in phase with fault
Superposing to obtain a neutral point voltage reference value
(6) Reference value of neutral point voltage
Real-time feedback quantity with neutral point voltage
Making a difference, and obtaining an arc suppression current reference value through a second PI controller
(7) Reference value of arc suppression current
And arc suppression current real-time feedback quantity
Making difference, and obtaining modulated wave voltage by means of third PI controller
(8) Modulating the wave voltage
Arc suppression current output by arc suppression current transformer controlled by PWM modulation
The invention does not need to measure the ground parameters and control the switching, and has simple control and high reliability.
Description
Technical Field
The invention relates to the technical field of power distribution networks, in particular to a power distribution network ground fault flexible regulation and control method considering network parameter influence.
Background
With the continuous enlargement of the scale of the power distribution network and the use of a large number of cable lines and nonlinear elements, the grounding fault current of the power distribution network is increased sharply, and the electric arc is difficult to extinguish by itself. The arc suppression coil can compensate the capacitive current of the ground fault and promote the rapid extinguishing of the electric arc, and is widely applied to the power distribution network. However, the arc suppression coil can only compensate the reactive component in the electric arc, and cannot compensate the active component and the harmonic component, so that the arc suppression effect is limited. Therefore, active flexible arc extinction research for realizing full compensation of ground fault current by using power electronic equipment is receiving wide attention.
Typical flexible arc extinction methods that have been proposed mainly include a flexible current arc extinction method, a flexible voltage arc extinction method, and a comprehensive flexible arc extinction method. The existing typical flexible voltage and current arc extinction method is difficult to simultaneously give consideration to the arc extinction requirements of high-resistance and low-resistance ground faults of a power distribution network; although the comprehensive flexible arc extinction method has the advantages of flexible voltage and current arc extinction, the problems of complex control switching and large switching transient impact exist.
A typical prior art soft crowbar process pair is shown in table 1. The flexible current arc extinction method needs to measure the ground parameters, and if the ground parameters are not accurately measured, the fault residual current is large, and the arc extinction effect is poor; and when high resistance ground connection, the flexible current arc extinction method has the problem of long arc extinction time. The flexible voltage arc extinction method adopts double closed loop control, and can be used for measuring the ground parameter, but when the ground is low in resistance, the arc extinction effect is poor due to the influence of line impedance and load current. The comprehensive flexible arc extinction method takes a ground fault resistor or neutral point voltage as a control switching condition, and adopts a voltage arc extinction method when the high resistance is grounded; when the low-resistance grounding is carried out, a current arc extinction method is adopted. Although the comprehensive flexible arc extinction method avoids the defects of flexible voltage arc extinction and flexible current arc extinction to a certain extent, the problems of complex switching control, large switching transient impact and the like exist.
TABLE 1 comparison of typical Flexible arc suppression methods
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects of the background technology, and provide a power distribution network ground fault flexible regulation and control method considering the influence of network parameters, which can effectively prevent arc reignition at a fault point, does not need to measure the ground parameters of a power distribution network line, does not need to control switching, and has simple control and high reliability.
The technical scheme adopted for solving the technical problem is that the method for flexibly regulating and controlling the ground fault of the power distribution network considering the influence of network parameters comprises the following steps of:
(1) connecting the arc suppression converter to a neutral point of the power distribution network;
(2) judging the fault condition of the power distribution network;
(3) calculating fault phase load current
(4) Loading the fault phase with current
Real-time feedback quantity of circuit current relative to fault phase
Making a difference, and obtaining the residual voltage compensation quantity of the fault point through a first PI controller
(5) Compensating residual voltage of fault point
Negative value of power supply voltage of phase-to-fault
Superposing to obtain a neutral point voltage reference value
(6) Reference value of neutral point voltage
Real-time feedback quantity with neutral point voltage
Making a difference, and obtaining an arc suppression current reference value through a second PI controller
(7) Reference value of arc suppression current
And arc-extinguishing current real-time feedback quantity
Making difference, and obtaining modulated wave voltage by means of third PI controller
(8) Modulating wave voltage
Obtaining control signal by PWM modulation, inputting the control signal to the arc suppression converter, and controlling the arc suppression converter to output arc suppression current
(9) And judging whether the fault is eliminated or not according to the arc extinction condition.
Further, in the step (2), the step of judging the fault condition of the power distribution network specifically comprises the following steps:
(2-1) detecting the neutral point voltage of the power distribution network when the power distribution network operates normally
And three-phase line current at power outlet
(2-2) after short delay, detecting the neutral point voltage of the power distribution network again
And three-phase line current at power outlet end
(2-3) calculating the current variation of the three-phase line;
wherein,
a is the phase line current variable quantity;
b is phase line current variable quantity;
c is the phase line current variable quantity;
(2-4) when the current variation of the three-phase line is zero or the three-phase line has the same magnitude, judging that the power distribution network has no ground fault, and updating the detection data of the neutral point voltage of the power distribution network and the current of the three-phase line at the power outlet end; when the phase of one phase in the current variation of the three-phase line is opposite to the other two phases and the amplitude is obviously larger than the other two phases, the power distribution network is judged to have the ground fault, the phase is judged to be a fault phase, and the fault phase is recorded as a fault phase
Further, in the step (3), the neutral point voltage before the fault is utilized
Three-phase line current at power outlet end before failure
Post fault neutral point voltage
Three-phase line current at power outlet end after fault
Calculating fault phase load current
If the phase a is the failed phase,
namely that
Calculating fault phase load current
The method specifically comprises the following steps:
(3-1) line Current satisfaction before Power distribution network failure
In the formula,
the current is the ground current of the three-phase line before the fault;
is a three-phase load current;
is a three-phase supply voltage; y isa、Yb、YcAdmittance to ground for the three-phase line;
line current is satisfied after power distribution network failure
In the formula,
the current is the ground current of the three-phase line after the fault;
is the fault point current;
the combined type (8) and the formula (9) obtain the variation of the line current before and after the fault as
(3-2) considering the unbalance of three-phase parameters to the ground,
satisfy the requirement of
The vertical type (8), (10) and (11) are connected to obtain the fault phase load current
Further, in the step (4), the residual voltage compensation quantity of the fault point
Is composed of
Wherein, Kp1Is the proportionality coefficient of the first PI controller, Ki1Is firstIntegral coefficient of PI controller, 1/S is integral function, Kp1＝4000，Ki1＝500。
Further, in the step (5), the neutral point voltage reference value
Is composed of
Further, in step (6), the reference value of the arc-extinguishing current
Is composed of
Wherein, Kp2Is the proportionality coefficient of the second PI controller, Ki2Is the integral coefficient of the second PI controller, 1/S is the integral function, Kp2＝2，Ki2＝1。
Further, in step (7), the wave voltage is modulated
Is composed of
Wherein, Kp3Is the proportionality coefficient of the third PI controller, Ki3Is the integration coefficient of the third PI controller, 1/S is the integration function, Kp3＝10，Ki3＝0.1。
Further, in the step (9), the specific method for judging whether the fault is eliminated according to the arc extinction condition is as follows: after short-time arc extinction, arc extinction current output by the arc extinction converter is reduced, and if the voltage of a neutral point of the power distribution network changes linearly, the ground fault is judged to be eliminated; otherwise, judging as a permanent ground fault, and isolating the fault line.
Compared with the prior art, the invention has the following advantages:
(1) the method provided by the invention considers the influence of the line impedance of the power distribution network, can inhibit the voltage of a fault point to be 0 under any grounding fault condition, and effectively prevents the arc reignition of the fault point.
(2) The method and the device do not need to measure the ground parameters of the power distribution network line and control switching, and have the advantages of simple control, high reliability and the like.
Drawings
Fig. 1 is a schematic diagram of a power distribution network with an arc suppression converter grounded.
Fig. 2 is a fault current flow diagram when the arc is not fully extinguished.
Fig. 3 is a fault current flow diagram for a fully extinguished arc.
Fig. 4 is a block diagram of the arc extinction control of the present invention.
FIG. 5 is a flow chart of the invention for extinguishing arcs
FIG. 6 shows the invention RfA comparison graph of simulated waveforms at 1000 Ω.
FIG. 7 shows the invention RfA comparison graph of simulated waveforms at 100 Ω.
FIG. 8 is a drawing of the invention RfA comparison graph of simulated waveforms at 5 Ω.
Detailed Description
The invention is described in further detail below with reference to the figures and the embodiments.
In order to solve the problem that the traditional flexible arc extinction method is difficult to adapt to various ground fault arc extinction requirements, the invention improves the arc extinction method, and provides a power distribution network ground fault flexible regulation and control method considering network parameter influence based on the improved arc extinction method.
The basic principle of the improved arc extinction method is as follows:
a typical power distribution network configuration with arc suppression converter grounding is shown in FIG. 1, wherein
Is a three-phase power supply voltage,
is a three-phase bus voltage and is,
is the neutral point voltage;
in order to extinguish the arc of the current injected by the converter,
is the three-phase line current at the power outlet end,
is a three-phase load current, and is,
is the current to ground of the three-phase line,
is the fault point current; r isa、rb、rcIs a three-phase line resistance to ground, Ca、Cb、CcFor three-phase line capacitance to ground, Z is the bus-to-fault line impedance, RfAnd T is a transformer.
The traditional voltage arc extinction method is influenced by line impedance and load current, and fault residual current exists at a fault point after arc extinction current is injected into an arc extinction converter. The equivalent control distribution network bus voltage is 0, and the fault current flow diagram is shown in figure 2. At this time, the fault phase voltage is lower, so that the fault phase has smaller relative earth capacitance current, and the fault phase line current is
Wherein,
is a point of failure residual flow.
If complete extinction of the fault point can be realized (i.e. complete extinction of the fault point
) The equivalent control fault point voltage is 0, and the distribution network fault current flow diagram is shown in fig. 3. At this time, the fault phase line current is
As can be seen from fig. 2 and 3, there is a distinct characteristic difference in the fault phase line current when the fault point current is fully extinguished versus not fully extinguished.
After a fault, the fault point voltage may be expressed as
From the formula (3), the conventional voltage arc suppression method controls
The voltage at the fault point can not be suppressed to 0 and the residual voltage at the fault point
Equal to the negative of the line impedance drop. To make it
The neutral point voltage reference should be
Because the fault point is uncertain, the line parameter Z cannot be solved. As can be seen from equation (2), complete arc extinction (i.e., 0 residual voltage at fault point) can be achieved as long as the control line current is equal to the load current. Therefore, the relation between the residual voltage of the fault point and the fault phase line current and the fault phase load current difference can be linearized:
as can be seen from the observation of the formula (5), if it can be eliminated
And
deviation between (i.e. the
) Then the residual voltage of the fault point can be caused
And 0, realizing complete arc extinction of the fault point. Based on the idea, the invention eliminates the adverse effect of line impedance voltage drop on arc extinction by adding a residual voltage compensation loop at the voltage reference value. The equivalent principle is shown in FIG. 3, and the residual voltage compensation amount is utilized
Counteracting the effects of line pressure drop.
In the control system of the air conditioner,
and
the delta can be steady state tracked using a PI or PR controller. In order to simplify the controller design, the present invention takes the PI controller as an example for analysis. Converting the line current control differential quantity into a fault residual voltage quantity through a PI (proportional-integral) controller, wherein the fault residual voltage quantity is represented by the following formula:
in formula (6), KpIs a proportionality coefficient, KiFor the integration coefficient, 1/S is the integration function.
Therefore, to suppress the fault point voltage to 0, the neutral point voltage reference value is:
according to the formula (7), the reference value of the neutral point voltage is required to be solved, and the negative value of the fault phase power supply voltage needs to be detected through a mutual inductor
Line current
And solving for the fault phase load current
Since the line impedance is much less than the ground-to-ground impedance, the calculation of the distribution network capacitance-to-ground current can approximately ignore the line impedance effect. So that line current is satisfied before power distribution network failure
In the formula (8), the reaction mixture is,
to be the pre-fault neutral point voltage,
for the pre-fault three-phase line current, Ya、Yb、YcIs the ground admittance of the three-phase line.
Most of the power distribution network ground faults are transient faults and indirect faults, and related simulation and experiments show that the flexible arc extinction can often suppress the fault current to be 0 in 1 power frequency period, so that the fluctuation of the load current can be ignored during the arc extinction period. Line current is satisfied after power distribution network failure
In the formula (9), the reaction mixture is,
to be the neutral point voltage after a fault,
is the three-phase line current after the fault.
The combined type (8) and the formula (9) obtain the variation of the line current before and after the fault as
When considering a three-phase parameter imbalance to ground,
satisfy the requirements of
The joint vertical type (8), (10) and (11) obtain the load current of the fault phase
When the phases b and c have ground faults, the load current of the corresponding fault phase can be calculated in the same way, and details are not repeated here.
The fault phase load current can be obtained by the formula (12) only by detecting the phase line current and the neutral point voltage before and after the fault. Then, the neutral point voltage reference value can be obtained by substituting the formula (12) for the formula (7). As can be seen from the reference value calculation results of the equations (12) and (7), the proposed arc suppression control does not use the line-to-ground parameter, and does not involve the measurement of the parameter.
The improved arc extinction method provided by the invention is shown in a control block diagram in fig. 4, and mainly comprises a residual voltage compensation ring, a voltage outer ring and a current inner ring. Firstly, the load current of the fault phase is calculated
Loading the fault phase with current
And line current
Making a difference, and obtaining the residual voltage compensation quantity of the fault point through a first PI controller
By negative value of fault phase supply voltage
As a reference, are superimposed
Back and neutral point voltage
Making a difference, and obtaining an arc suppression current reference value through a second PI controller
And arc-extinguishing current real-time feedback quantity
Making difference, and obtaining modulation wave by using third PI controller
And obtaining a control signal of the arc suppression converter by PWM modulation.
As shown in the formula (10), when the power distribution network has no ground fault, the line current variation is 0; when the distribution network has a ground fault, the current variation of the fault phase circuit is obviously larger than that of the non-fault phase, and the phase variation of the fault phase current is opposite to that of the non-fault phase current according to the KCL law. Therefore, the formula (10) can be used as a judgment condition for power distribution network fault sensing and fault phase selection.
The arc extinction implementation flow is shown in fig. 5. Firstly, whether a fault occurs is judged according to the neutral point voltage and the line current. When the power distribution network does not have a fault, updating and storing data; if the earth fault occurs, judging a fault phase, and calculating and injecting arc extinction current by using an improved arc extinction method; after the delay, the injected crowbar current is reduced to determine whether the fault is eliminated. If the fault is eliminated, the power distribution network recovers normal operation; if the fault is not eliminated, the fault is judged to be a permanent fault, and a fault line is selected and isolated.
Therefore, in this embodiment, based on the improved arc extinction method, a power distribution network ground fault flexible regulation and control method considering network parameter influence is provided, which includes the following steps:
(1) and connecting the arc suppression converter to a neutral point of a power distribution network through a step-up transformer, and performing grounding treatment on the arc suppression converter through the step-up transformer.
(2) And judging the fault condition of the power distribution network.
(3) Calculating fault phase load current
(4) Loading the fault phase with current
Real-time feedback quantity of current of phase line with fault
Making a difference, and obtaining the residual voltage compensation quantity of the fault point through a first PI controller
Wherein, Kp1Is the proportionality coefficient of the first PI controller, Ki1Is the integral coefficient of the first PI controller, 1/S is the integral function, in this embodiment, Kp1＝4000，Ki1＝500。
(5) Compensating residual voltage of fault point
Negative value of power supply voltage of phase-to-fault
Superposing to obtain a neutral point voltage reference value
(6) Reference value of neutral point voltage
Real-time feedback quantity with neutral point voltage
Making a difference, and obtaining an arc extinction current reference value through a second PI controller
Wherein, Kp2Is the proportionality coefficient of the second PI controller, Ki2Is the integral coefficient of the second PI controller, 1/S is the integral function, in this embodiment, Kp2＝2，Ki2＝1。
(7) Reference value of arc suppression current
Arc suppression current real-time feedback quantity output in real time with arc suppression current transformer
Making difference, and obtaining modulated wave voltage by means of third PI controller
Wherein, Kp3Is the proportionality coefficient of the third PI controller, Ki3Is the integration coefficient of the third PI controller, 1/S is the integration function, in this embodiment, Kp3＝10，Ki3＝0.1。
(8) Modulating the wave voltage
Obtaining control signal by PWM modulation, inputting the control signal to the arc suppression converter, and controlling the arc suppression converter to output arc suppression current
(9) And judging whether the fault is eliminated or not according to the arc extinction condition. The method specifically comprises the following steps: after short-time arc extinction, arc extinction current output by the arc extinction converter is reduced, and if the voltage of a neutral point of the power distribution network changes linearly, the elimination of the ground fault is judged; otherwise, a permanent ground fault is determined, and the fault line is isolated, in the embodiment, the short arc extinction time is 10 power frequency periods, and in specific application, the short arc extinction time can be 3-15 power frequency periods.
In the step (2), the step of judging the fault condition of the power distribution network specifically comprises the following steps:
(2-1) detecting the neutral point voltage of the power distribution network when the power distribution network operates normally
And three-phase line current at power outlet end
(2-2) after short delay, detecting the voltage of the neutral point of the power distribution network again
And three-phase line current at power outlet
In this embodiment, the short-time delay is a delay of 1 power frequency cycle.
(2-3) calculating the current variation of the three-phase line;
wherein,
is a phase line current variable quantity;
b is phase line current variable quantity;
is the c-phase line current variation.
(2-4) when the current variation of the three-phase line is zero or the three-phase line has the same magnitude, judging that the power distribution network has no ground fault, and further judging that the power distribution network has no ground faultNewly allocating detection data of the neutral point voltage of the power grid and the current of the three-phase line at the power outlet end; when the phase of one phase in the current variation of the three-phase line is opposite to the other two phases and the amplitude is obviously larger than the other two phases, the power distribution network is judged to have the ground fault, the phase is judged to be a fault phase, and the fault phase is recorded as
Is one of the phases a, b and c, in this embodiment,
is a phase. Said clearly larger than theoretically this phase amplitude A1Is the amplitude A of the other two phases2、A3In practice, significantly greater than can be expressed as A1≥0.6(A2+A3)。
In the step (3), the neutral point voltage before the fault is utilized
Three-phase line current at power outlet end before fault
Post-fault neutral point voltage
Three-phase line current at power outlet end after fault
Calculating fault phase load current
In this embodiment, since the phase a is the failure phase,
namely, it is
Calculating fault phase load current
The method specifically comprises the following steps:
(3-1) line current is satisfied before the power distribution network fails
In the formula,
the current is the ground current of the three-phase line before the fault;
is a three-phase load current;
is a three-phase supply voltage; y isa、Yb、YcIs the ground admittance of the three-phase line.
Line current is satisfied after power distribution network failure
In the formula,
the current is the ground current of the three-phase line after the fault;
is the fault point current.
The combined type (8) and the formula (9) obtain the variation of the line current before and after the fault as
(3-2) when considering the three-phase parameter unbalance to ground,
satisfy the requirement of
The vertical type (8), (10) and (11) are connected to obtain the fault phase load current
When other phase faults are such as b or c phase faults, the specific calculation method of the b or c phase load current is the same as that of the a phase load current
The description will not be repeated here.
In order to better prove the effectiveness of the method provided by the invention, the following verification is carried out by combining a simulation example. According to the structure diagram of the power distribution network shown in FIG. 1, a simulation platform is built in MATLAB/Simulink, and simulation parameters are shown in Table 2.
TABLE 2 simulation parameters
Respectively carrying out grounding resistance R according to the simulation model of the power distribution network structure shown in figure 1fThe simulation is verified for 1000 omega, 100 omega and 5 omega, as shown in FIGS. 6-8. Setting the time period between 0.1s and 0.15s, and enabling the power grid to normally operate; and when the time is 0.15s, the power distribution network has a ground fault, and the arc extinction action time of the arc extinction converter is delayed in order to better compare the change of the fault point current before and after arc extinction. When the time is 0.2-03s, a traditional voltage arc extinction method is adopted; at 0.3-0.4s, the arc extinction method provided by the invention is adopted.
As can be seen from the waveforms of fig. 6-8, the arc suppression converter employs a conventional voltage suppression control that controls the neutral voltage to be equal to the negative value of the fault phase supply voltage during the 0.2-0.3s period. When the high resistance is grounded, the arc extinction effect is good; when the low-resistance grounding is carried out, the fault residual current is large, and the arc extinction effect is poor. During 0.3-0.4s, the arc suppression converter is controlled by the arc suppression method provided by the invention, wherein the neutral point power supply voltage is smaller than the power supply voltage amplitude. No matter the grounding resistance is high resistance or low resistance, the arc extinction method provided by the invention can effectively and quickly suppress the current of the fault point.
Various modifications and variations of the present invention may be made by those skilled in the art, and they are also within the scope of the present invention provided they are within the scope of the claims of the present invention and their equivalents.
What is not described in detail in the specification is prior art that is well known to those skilled in the art.
Claims (5)
1. A distribution network ground fault flexible regulation and control method considering network parameter influence is characterized in that: the method comprises the following steps:
(1) connecting an arc suppression converter to a neutral point of a power distribution network;
(2) judging the fault condition of the power distribution network;
(3) calculating fault phase load current
(4) Loading the fault phase with current
Real-time feedback quantity of current of phase line with fault
Making a difference, and obtaining the residual voltage compensation quantity of the fault point through a first PI controller
(5) Compensating residual voltage of fault point
Negative value of power supply voltage in phase with fault
Superposing to obtain a neutral point voltage reference value
(6) Reference value of neutral point voltage
Real-time feedback quantity with neutral point voltage
Making a difference, and obtaining an arc suppression current reference value through a second PI controller
(7) Reference value of arc suppression current
And arc suppression current real-time feedback quantity
Making difference, and obtaining modulated wave voltage by means of third PI controller
(8) Modulating the wave voltage
Obtaining a control signal through PWM modulation, inputting the control signal to the arc suppression converter, and controlling the arc suppression converter to output arc suppression current
(9) Judging whether the fault is eliminated according to the arc extinction condition;
in the step (2), the step of judging the fault condition of the power distribution network specifically comprises the following steps:
(2-1) detecting the neutral point voltage of the power distribution network when the power distribution network operates normally
And three-phase line current at power outlet end
(2-2) after short delay, detecting the voltage of the neutral point of the power distribution network again
And three-phase line current at power outlet
(2-3) calculating the current variation of the three-phase line;
wherein,
a is the phase line current variable quantity;
b is phase line current variable quantity;
c is the phase circuit current variable quantity;
(2-4) when the current variation of the three-phase line is zero or the three-phase line has the same magnitude, judging that the power distribution network has no ground fault, and updating the detection data of the neutral point voltage of the power distribution network and the current of the three-phase line at the power outlet end; when the phase of one phase in the current variation of the three-phase line is opposite to the other two phases and the amplitude is obviously larger than the other two phases, the power distribution network is judged to have the ground fault, the phase is judged to be a fault phase, and the fault phase is recorded as
In the step (3), the neutral point voltage before the fault is utilized
Three-phase line current at power outlet end before failure
Post fault neutral point voltage
Three-phase line current at power outlet end after fault
Calculating fault phase load current
If the phase a is the failed phase,
namely, it is
Calculating fault phase load current
The method specifically comprises the following steps:
(3-1) line Current satisfaction before Power distribution network failure
In the formula,
the current is the ground current of the three-phase line before the fault;
is a three-phase load current;
is a three-phase supply voltage; y isa、Yb、YcAdmittance to ground for the three-phase line;
line current is satisfied after power distribution network failure
In the formula,
the three-phase line is the ground current after the fault;
is the fault point current;
the combined type (8) and the formula (9) obtain the variation of the line current before and after the fault as
(3-2) considering the unbalance of three-phase parameters to the ground,
satisfy the requirements of
The joint vertical type (8), (10) and (11) obtain the load current of the fault phase
In the step (9), the specific method for judging whether the fault is eliminated according to the arc extinction condition is as follows: after short-time arc extinction, arc extinction current output by the arc extinction converter is reduced, and if the voltage of a neutral point of the power distribution network changes linearly, the elimination of the ground fault is judged; otherwise, the permanent earth fault is judged, and the fault line is isolated.
2. The power distribution network ground fault flexible regulation and control method considering network parameter influence according to claim 1, characterized in that: in the step (4), the residual voltage compensation quantity of the fault point
Is composed of
Wherein, Kp1Is the proportionality coefficient of the first PI controller, Ki1Is the integral coefficient of the first PI controller, 1/S is the integral function, Kp1＝4000，Ki1＝500。
3. The method for flexibly regulating and controlling the ground fault of the power distribution network considering the influence of the network parameters, according to claim 2, is characterized in that: in step (5), the reference value of the neutral point voltage
Is composed of
4. The method for flexibly regulating and controlling the ground fault of the power distribution network considering the influence of the network parameters, according to claim 1, is characterized in that: in step (6), the reference value of the arc-suppression current
Is composed of
Wherein, Kp2Is the proportionality coefficient of the second PI controller, Ki2Is the integral coefficient of the second PI controller, 1/S is the integral function, Kp2＝2，Ki2＝1。
5. The method for flexibly regulating and controlling the ground fault of the power distribution network considering the influence of the network parameters, according to claim 1, is characterized in that: in step (7), the wave voltage is modulated
Is composed of
Wherein, Kp3Is the proportionality coefficient of the third PI controller, Ki3Being a third PI controllerIntegral coefficient, 1/S is integral function, Kp3＝10，Ki3＝0.1。
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| CN104218563A (en) * | 2014-09-26 | 2014-12-17 | 福州大学 | Power distribution network fault arc extinction method by connecting neutral point to the ground through multi-level converter |
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| CN113097989A (en) * | 2021-04-16 | 2021-07-09 | 长沙理工大学 | Fault composite arc extinction method for flexible grounding power distribution network |
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| CN105610147B (en) * | 2016-03-24 | 2018-03-16 | 福州大学 | A kind of distribution network ground fault arc extinction method based on three-phase cascaded H-bridges current transformer |
| CN109510187B (en) * | 2018-11-01 | 2020-10-16 | 杭州求是电力技术有限公司 | Resonant grounding system fault phase residual voltage suppression method based on active adjustable complex impedance accurate tuning control |
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| CN104218563A (en) * | 2014-09-26 | 2014-12-17 | 福州大学 | Power distribution network fault arc extinction method by connecting neutral point to the ground through multi-level converter |
| CN112350293A (en) * | 2020-10-30 | 2021-02-09 | 西安工程大学 | Active arc extinction method for single-phase earth fault of power distribution network with secondary injection current |
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