1. The utility model provides a distribution network machine carries line fault simulation experiment system, includes full compensation control module, self-adaptation zero sequence admittance measuring module and PWM control's processing chip, its characterized in that: the full compensation control module is a compensation mode combining pre-regulation and random regulation, the full compensation control module is internally divided into a normal state unit and a fault response unit, the self-adaptive zero sequence admittance measuring module adopts a differential algorithm, fault recording data are recorded in the normal state unit of the full compensation control module, the normal state unit is internally detected by an arc suppression coil controller at regular time, the neutral point voltage U0, the main coil gear and the reactance value L1 are detected, the detection values of the neutral point voltage U0, the main coil gear and the reactance value L1 all calculate the ground capacitance value C0 of the current system by using a capacitance current detection algorithm, the fault response unit comprises a starting fault line selection program, the starting fault line selection program internally comprises a quick line selection algorithm module and a quick harmonic analysis algorithm module respectively, the output end of the quick line selection algorithm module is correspondingly connected with the input end of the quick harmonic analysis algorithm module, the output end of the rapid harmonic analysis algorithm module is connected with a full current estimation algorithm module, the output end of the full current estimation algorithm module is connected with a compensation current generation algorithm module, the PWM-controlled processing chip can complete complex algorithms including sampling, current tracking, instruction operation, PWM driving signal generation and the like, and the PWM-controlled processing chip is used for controlling power devices of the slave arc suppression coil inverter, so that the grounding current is effectively compensated and the working condition of the inverter is monitored.

2. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: and comparing the ground capacitance value C0 of the current system with the gear switching value of the main coil, and if the ground capacitance value C0 of the current system is not properly compared with the gear switching value of the main coil by using a gear shifting algorithm, shifting the main coil to a gear with the overcompensation rate of 15% according to a gear shifting instruction.

3. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: the fault recording data is subjected to data analysis by using a fast harmonic analysis algorithm, zero sequence fundamental wave reactive current values of all lines under various conditions of single-phase earth faults are calculated, earth capacitance C1 and the proportion of all lines are calculated, and current distortion components under different single-phase earth faults are calculated.

4. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: the fault response unit detects zero-sequence currents I01, I02 and … … I0n of lines according to single-phase ground fault signals, the fast line selection algorithm module and the fast harmonic analysis algorithm module analyze and obtain the zero-sequence current I0m at a fault line outlet according to the zero-sequence currents I01, I02 and … … I0n of the detected lines, and the full current estimation algorithm module performs full current estimation on the ground capacitance C0 and the fault line capacitance and a current distortion empirical value under the fault condition by using the zero-sequence current I0m at the fault line outlet and a system calculated under a normal state to obtain the fault current If of the whole system containing fault line ground current, power component and harmonic component.

5. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: and the fault response unit detects and detects the compensation current IL1 of the current main coil and the active slave arc suppression coil according to a single-phase ground fault signal, wherein IL2 is If-IL1, and IL2 applies an active inversion algorithm to generate a power device driving signal to control the active slave arc suppression coil to perform full compensation.

6. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: the method comprises the steps that a harmonic current detection algorithm adopted in a rapid line selection algorithm module separates components of system fault current except a fault line, harmonic and active components are estimated according to a scale factor k obtained by an intelligent grounding current estimation algorithm when the system is normal, a full current estimation algorithm adopted in a full current estimation algorithm module estimates fundamental wave capacitance current of the fault current according to neutral point voltage of a fault state and predicted system total current, and the two estimated values are added to obtain estimated If of the fault full current.

7. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: the arc suppression coil controller adopts a composite ground current detection technology, the composite ground current detection technology is based on the original power grid ground current detection technologies such as a two-point method, a three-point method, an E0 method and the like, the structural characteristics of the active arc suppression coil are combined, a composite power grid capacitance current detection algorithm combined with an injection signal method is adopted to detect the power grid ground capacitance current, and meanwhile, when the power grid has a single-phase ground fault, an intelligent fitting method combined with a network structure and data recording provides accurate ground fault current active full compensation reference for the active arc suppression coil.

8. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: the self-adaptive zero sequence admittance measuring module detects high and low resistance faults and simultaneously accurately selects lines according to the principles of an improved transient method and a zero sequence admittance method.

9. The power distribution network airborne line fault simulation experiment system according to claim 1, characterized in that: the processing chip of the PWM control is a digital signal processor TMS320F2812, a 16-way 12-bit precision AD conversion module is integrated inside the digital signal processor TMS320F2812, the EVA of the digital signal processor TMS320F2812 provides a one-bit, low-active, power device protection pin PDPINTA, the PWM controlled processing chip supports 17 CPU level interrupts, including 1 non-maskable interrupt (NMI) and 16 maskable interrupts, the AD conversion module is programmed to control the power-up process of the reference circuit, the reference level of the AD conversion module and the length of the sampling/holding window are selected, the sampling mode of the AD conversion module is a cascade mode, the sampling trigger mode of the AD conversion module is triggered by an EVA event, the AD conversion module allows an interrupt request to be sent to a peripheral interrupt manager, the AD conversion module samples two channels for sorting, 2 channels are repeatedly sampled for 4 times, and the sorter is automatically reset after sampling is completed; and resetting the AD conversion module and resetting the interrupt flag bit.

10. The power distribution network airborne line fault simulation experiment system of claim 9, wherein: the AD conversion module chip is internally and externally provided with two event managers EVA and EVB, the two event managers comprise two general timers (GP), two general timer comparators, a three-phase PWM unit, a capture unit and a quadrature encoding pulse circuit (QEP), each EV can generate two PWM signals independently controlled by the two timers and 3 complementary PWM signals controlled by the same timer, the EVA comprises a pin PWM1 and a pin PWM2, the signal frequency of the pin PWM1 and the pin PWM2 is 10kHz, the dead time is set to be 6uS, and the initialization work executed on the EVA module in the process of executing a program comprises the following steps: configuring a general output pin of an EV function, allowing EVA interruption not to send an interruption request to a peripheral interruption manager, enabling PWM output, setting dead time to realize output polarity selection of each pin, enabling PWM1 and PWM2 to be high-effective and low-effective respectively, enabling a work register reloading condition of each control register and a TIMER to be immediately reloaded, enabling an AD trigger source to be a TIMER1 underflow event, assigning a TIMER1 period register T1PR, assigning an initial value to a counting register T1CNT, assigning an initial value to a PWM comparison register PWM1, and starting the TIMER.

Background

At present, the research on the ground fault protection of the power distribution network mainly focuses on the aspects of line selection and positioning of low-current ground faults, and the focus of attention is mainly on improving the practicability level of a line selection device and the success rate of integral line selection, and the research on how to actively and quickly compensate the ground fault current so as to eliminate arc light and reduce electric shock accidents is also lacked.

From practical work we conclude that the sensitivity and reliability decisions in any way also depend on the magnitude of the ground current, which in turn is closely related to the way the neutral point of the distribution network is grounded. In order to solve the problem of electric shock protection, some power supply enterprises change a neutral point grounding mode of a power distribution network into a low-resistance grounding mode, hope to avoid the problem of low-current grounding fault protection, and timely trip and remove a fault line when a human body gets an electric shock or a lead falls to the ground. However, theoretical analysis and engineering practice show that, in the current technology, the ground protection reaction ground resistance of the low-resistance grounding distribution network is only about 300 Ω, and the change of the neutral point grounding mode into the low-resistance mode not only can not reliably alarm and trip when high-resistance grounding faults occur, but also increases the difficulty of solving the problems.

Disclosure of Invention

The invention mainly aims to provide a power distribution network airborne line fault simulation experiment system which can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a power distribution network airborne line fault simulation experiment system comprises a full compensation control module, a self-adaptive zero sequence admittance measuring module and a PWM control processing chip, wherein the full compensation control module is a compensation mode combining pre-regulation and random regulation, the full compensation control module is internally divided into a normal state unit and a fault response unit, the self-adaptive zero sequence admittance measuring module adopts a difference algorithm, fault recording data are recorded in the normal state unit of the full compensation control module, the normal state unit is internally detected for a neutral point voltage U0, a main coil gear and a reactance value L1 through an arc suppression coil controller at regular time, detection values of the neutral point voltage U0, the main coil gear and the reactance value L1 calculate a ground capacitance value C0 of the current system by using a capacitance current detection algorithm, and the fault response unit comprises a starting fault line selection program, the starting fault line selection program comprises a quick line selection algorithm module and a quick harmonic analysis algorithm module respectively, the output end of the quick line selection algorithm module is correspondingly connected with the input end of the quick harmonic analysis algorithm module, the output end of the quick harmonic analysis algorithm module is connected with a full current estimation algorithm module, the output end of the full current estimation algorithm module is connected with a compensation current generation algorithm module, a PWM (pulse-width modulation) controlled processing chip can complete complex algorithms including sampling, current tracking, instruction operation, PWM driving signal generation and the like, and the PWM controlled processing chip is used for controlling a power device of a slave arc suppression coil inverter, so that the grounding current is effectively compensated and the working condition of the inverter is monitored.

Preferably, the ground capacitance value C0 of the current system is compared with the main coil gear switching value, and if the ground capacitance value C0 of the current system is not properly compared with the main coil gear switching value by using a gear shifting algorithm, the main coil is shifted to a gear near 15% overcompensation according to a gear shifting instruction.

Preferably, the fault recording data is subjected to data analysis by using a fast harmonic analysis algorithm, zero sequence fundamental wave reactive current values of all lines under various conditions of single-phase ground faults are calculated, and the ground capacitance C1 and the proportion of all lines are calculated, and current distortion components under different single-phase ground faults are calculated.

Preferably, the fault response unit detects line zero-sequence currents I01, I02, … … I0n according to a single-phase ground fault signal, the fast line selection algorithm module and the fast harmonic analysis algorithm module analyze and obtain zero-sequence currents I0m at the fault line outlet according to the detected line zero-sequence currents I01, I02, … … I0n, and the full current estimation algorithm module performs full current estimation on the ground capacitance C0, the fault line capacitance and the current distortion empirical value under the fault condition by using the zero-sequence currents I0m at the fault line outlet and the system calculated under the normal state, so as to obtain fault currents If of the whole system including fault line ground currents, power components and harmonic components.

Preferably, the fault response unit detects and detects the compensation current IL1 of the current main coil and the active slave arc suppression coil according to a single-phase ground fault signal, wherein IL2 is If-IL1, and IL2 applies an active inversion algorithm to generate a power device driving signal to control the active slave arc suppression coil to perform full compensation.

Preferably, a harmonic current detection algorithm adopted in the fast line selection algorithm module separates components of the system fault current except the fault line, estimates harmonic and active components according to a scale factor k obtained by an intelligent grounding current estimation algorithm when the system is normal, and a full current estimation algorithm adopted in the full current estimation algorithm module estimates fundamental wave capacitance current of the fault current according to neutral point voltage of the fault state and predicted system total current, and adds the two estimated values to obtain an estimated If of the fault full current.

Preferably, the arc suppression coil controller adopts a composite ground current detection technology, the composite ground current detection technology is based on the original two-point method, three-point method, E0 method and other power grid ground current detection technologies, combines the structural characteristics of the active arc suppression coil, adopts a composite power grid capacitance current detection algorithm combined with an injection signal method to detect the power grid ground capacitance current, and simultaneously, when the power grid has a single-phase ground fault, the intelligent fitting method combined with a network structure and data recording provides accurate ground fault current active full compensation reference for the active arc suppression coil.

Preferably, the adaptive zero sequence admittance measuring module detects high and low resistance faults and simultaneously selects lines accurately according to the principles of an improved transient method and a zero sequence admittance method.

Preferably, the PWM controlled processing chip is a digital signal processor TMS320F2812, a 16-way 12-bit precision AD conversion module is integrated inside the digital signal processor TMS320F2812, the EVA of the digital signal processor TMS320F2812 provides a one-bit, low-active, power device protection pin PDPINTA, the PWM controlled processing chip supports 17 CPU level interrupts, including 1 non-maskable interrupt (NMI) and 16 maskable interrupts, the AD conversion module is programmed to control the power-up process of the reference circuit, the reference level of the AD conversion module and the length of the sampling/holding window are selected, the sampling mode of the AD conversion module is a cascade mode, the sampling trigger mode of the AD conversion module is triggered by an EVA event, the AD conversion module allows an interrupt request to be sent to a peripheral interrupt manager, the AD conversion module samples two channels for sorting, 2 channels are repeatedly sampled for 4 times, and the sorter is automatically reset after sampling is completed; and resetting the AD conversion module and resetting the interrupt flag bit.

Preferably, two event managers EVA and EVB are arranged inside and outside the AD conversion module chip, and each event manager includes two general timers (GP), two general timer comparators, a three-phase PWM unit, a capture unit and a quadrature pulse code circuit (QEP), each EV can generate two routes of PWM signals independently controlled by the two timers and 3 sets of complementary PWM signals controlled by the same timer, the EVA includes a pin PWM1 and a pin PWM2, the signal frequencies of the pin PWM1 and the pin PWM2 are both 10kHz, the dead time is set to 6uS, and the initialization work performed on the EVA module when executing the program includes: configuring a general output pin of an EV function, allowing EVA interruption not to send an interruption request to a peripheral interruption manager, enabling PWM output, setting dead time to realize output polarity selection of each pin, enabling PWM1 and PWM2 to be high-effective and low-effective respectively, enabling a work register reloading condition of each control register and a TIMER to be immediately reloaded, enabling an AD trigger source to be a TIMER1 underflow event, assigning a TIMER1 period register T1PR, assigning an initial value to a counting register T1CNT, assigning an initial value to a PWM comparison register PWM1, and starting the TIMER.

Compared with the prior art, the invention has the following beneficial effects:

1. in the invention, the self-adaptive zero sequence admittance measuring module adopts a differential algorithm, and can eliminate the measuring errors of zero sequence CT and open triangle PT devices by using a differential principle GFN, then treat the unbalanced voltage of a power grid and adjust the detuning equivalence to be in a proper range.

2. According to the invention, the current state value of the system is accurately calculated through an algorithm with a complex fast line selection algorithm, a fast harmonic analysis algorithm, a full current estimation algorithm and a compensation current generation algorithm, the residual current compensator injects current from a neutral point, the residual current is equal to the residual current in magnitude and opposite in direction, the residual current is thoroughly eliminated, a user does not power off, the power supply reliability is greatly improved, and the complete compensation grounding current is almost zero.

3. According to the invention, by utilizing the inherent zero sequence characteristic of the three-phase grid system but not used usually, the system improves the protection of the grid to a new performance level in various aspects, and almost reaches all measurement references, namely mobility, sensitivity and selectivity, as excellent protection.

4. In the invention, by utilizing the principles of an improved transient method and a zero sequence admittance method, high and low resistance faults are detected, and simultaneously, the line selection is accurate, the accuracy rate of the line selection is close to 100 percent, and the extremely sensitive differential measurement is independent of the measurement accuracy of the current transformer.

5. The arc suppression coil controller adopts a composite grounding current detection technology, and on the basis of the original power grid grounding current detection technologies such as a two-point method, a three-point method, an E0 method and the like, the structural characteristics of the active arc suppression coil are combined, a composite power grid capacitance current detection algorithm combined with an injection signal method is adopted to detect the power grid grounding capacitance current, a basis is provided for the automatic tuning of a turn-adjusting type arc suppression coil, and meanwhile, an intelligent fitting method capable of combining a network structure and data recording provides accurate active full compensation reference for the grounding fault current for the active arc suppression coil.

Drawings

FIG. 1 is a schematic flow diagram of full compensation control of an airborne line fault simulation experiment system of a power distribution network according to the present invention;

FIG. 2 is a circuit diagram of a control signal flow of the power distribution network airborne line fault simulation experiment system of the present invention;

fig. 3 is a schematic structural diagram of a flow chart of a slave arc suppression coil PWM control procedure of the power distribution network airborne line fault simulation experiment system of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1-3, a power distribution network airborne line fault simulation experiment system includes a full compensation control module, a self-adaptive zero-sequence admittance measurement module and a PWM-controlled processing chip, wherein the full compensation control module is a compensation mode combining pre-adjustment and random adjustment, and the full compensation control module is internally divided into a normal state unit and a fault response unit, the self-adaptive zero-sequence admittance measurement module adopts a differential algorithm, fault recording data is recorded in the normal state unit of the full compensation control module, the normal state unit is internally timed by an arc suppression coil controller to detect a neutral point voltage U0, a main coil gear and a reactance value L1, and detection values of the neutral point voltage U0, the main coil gear and the reactance value L1 all calculate a ground capacitance value C0 of the current system by using a capacitance current detection algorithm, the fault response unit includes a starting fault line selection program, the starting fault line selection program comprises a quick line selection algorithm module and a quick harmonic analysis algorithm module respectively, the output end of the quick line selection algorithm module is correspondingly connected with the input end of the quick harmonic analysis algorithm module, the output end of the quick harmonic analysis algorithm module is connected with a full current estimation algorithm module, the output end of the full current estimation algorithm module is connected with a compensation current generation algorithm module, a PWM (pulse-width modulation) controlled processing chip can complete complex algorithms including sampling, current tracking, instruction operation, PWM driving signal generation and the like, and the PWM controlled processing chip is used for controlling power devices of a slave arc suppression coil inverter, so that the grounding current is effectively compensated and the working condition of the inverter is monitored.

Comparing the ground capacitance value C0 of the current system with the gear switching value of the main coil, and if the ground capacitance value C0 of the current system is not proper to the gear switching value of the main coil by using a gear shifting algorithm, shifting the main coil to a gear near 15% overcompensation according to a gear shifting instruction; the fault recording data are subjected to data analysis by using a fast harmonic analysis algorithm, zero sequence fundamental wave reactive current values of all lines under various conditions of single-phase earth faults are calculated, earth capacitance C1 and the proportion of all lines are calculated, and current distortion components under different single-phase earth faults are calculated; the method comprises the steps that the interior of a fault response unit detects zero-sequence currents I01, I02 and … … I0n of a line according to a single-phase ground fault signal, a quick line selection algorithm module and a quick harmonic analysis algorithm module analyze and obtain zero-sequence currents I0m at a fault line outlet according to zero-sequence currents I01, I02 and … … I0n of the detected line, a full current estimation algorithm module carries out full current estimation on the fault by using the zero-sequence currents I0m at the fault line outlet, a system ground capacitance C0 calculated in a normal state, the capacitance of a fault line and a current distortion empirical value under the fault condition to obtain fault currents If of the whole system containing fault line ground currents, power components and harmonic components, a complex algorithm is used for accurately calculating the current state value of the system, currents are injected from a neutral point through a residual current compensator, the current is equal in size and opposite in direction to thoroughly eliminate residual currents; the compensation current IL1 of the current main coil and the active slave arc suppression coil is detected and detected in the fault response unit according to the single-phase ground fault signal, IL2 is If-IL1, and IL2 applies an active inversion algorithm to generate a power device driving signal to control the active slave arc suppression coil to carry out full compensation; the method comprises the steps that a harmonic current detection algorithm adopted in a fast line selection algorithm module separates components of system fault current except a fault line, harmonic and active components are estimated according to a scale factor k obtained by an intelligent grounding current estimation algorithm when the system is normal, a full current estimation algorithm adopted in a full current estimation algorithm module estimates fundamental wave capacitance current of the fault current according to neutral point voltage of a fault state and predicted system total current, and the two estimated values are added to obtain estimated If of the full current of the fault; the arc suppression coil controller adopts a composite grounding current detection technology, the composite grounding current detection technology is based on the original two-point method, three-point method, E0 method and other power grid grounding current detection technologies, combines the structural characteristics of the active arc suppression coil, adopts a composite power grid capacitance current detection algorithm combined with an injection signal method to detect the power grid grounding capacitance current, and simultaneously, when the power grid has a single-phase grounding fault, the intelligent fitting method combined with a network structure and data recording provides an accurate grounding fault current active full compensation reference for the active arc suppression coil so as to ensure the requirement of accurate arc suppression control; the self-adaptive zero sequence admittance measuring module detects high and low resistance faults and simultaneously accurately selects lines according to the principles of the improved transient method and the zero sequence admittance method, the accuracy rate of the line selection is close to 100 percent, and the extremely sensitive differential measurement (the measurement error of equipment is eliminated) is irrelevant to the measurement accuracy of a current transformer; the PWM controlled processing chip is a digital signal processor TMS320F2812, a 16-way 12-bit precision AD conversion module is integrated in the digital signal processor TMS320F2812, and EVA of the digital signal processor TMS320F2812 provides a one-bit low-effective power device protection pin PDPINTA for protecting a power device under the conditions of overload, overheating, undervoltage and the like. The external interrupt generated by the low level of the pin is the highest level in an interrupt vector group 1, on the AD sampling interrupt, after the interrupt responds, a CPU automatically sets a PWM signal output pin to be in a high-impedance state to block a driving signal, a processing chip controlled by the PWM supports 17 CPU level interrupts, wherein the CPU level interrupts comprise 1 non-maskable interrupt (NMI) and 16 maskable interrupts, an AD conversion module refers to the circuit for programming control of the power-on process, the AD conversion module refers to the level and the length of a sampling/holding window for selection, the sampling mode of the AD conversion module is a cascade mode, the sampling trigger mode of the AD conversion module is EVA event trigger, the AD conversion module allows an interrupt request to be sent to an external interrupt manager, the AD conversion module samples two channels for sorting, 2 channels are repeatedly sampled for 4 times, and the sorter is automatically reset after the sampling is completed; resetting the AD conversion module, and resetting the interrupt flag bit; the AD conversion module chip is internally and externally provided with two event managers EVA and EVB, the two event managers comprise two general timers (GP), two general timer comparators, a three-phase PWM unit, a capture unit and a quadrature encoding pulse circuit (QEP), each EV can generate two PWM signals independently controlled by the two timers and 3 groups of complementary PWM signals controlled by the same timer, the EVA comprises a pin PWM1 and a pin PWM2, the signal frequency of the pin PWM1 and the pin PWM2 is 10kHz, the dead time is set to be 6uS, and the initialization work executed on the EVA module in the process of executing a program comprises the following steps: configuring a general output pin of an EV function, allowing EVA interruption not to send an interruption request to a peripheral interruption manager, enabling PWM output, setting dead time to realize output polarity selection of each pin, enabling PWM1 and PWM2 to be high-effective and low-effective respectively, enabling a work register reloading condition of each control register and a TIMER to be immediately reloaded, enabling an AD trigger source to be a TIMER1 underflow event, assigning a TIMER1 period register T1PR, assigning an initial value to a counting register T1CNT, assigning an initial value to a PWM comparison register PWM1, and starting the TIMER.

The invention provides a full compensation control mode according to a compensation mode combining preset regulation and random regulation, wherein the control mode is divided into a normal state and a fault response part, and iL2 is iF-iL 1; under the normal state: the controller of the arc suppression coil detects neutral point voltage U0, main coil gear and reactance value L1 at regular time, and calculates the ground capacitance value C0 of the current system by using a ground capacitance current detection algorithm; checking whether the gear of the main coil is proper or not by using a real-time calculation result, and adjusting the main coil to a gear with the overcompensation rate of 15% if the gear of the main coil is not proper; analyzing historical fault recording data, calculating zero sequence fundamental wave reactive current values of all lines under various conditions of single-phase earth faults, calculating the earth capacitance and the occupied proportion of all lines and current distortion components under different single-phase earth faults; fault response: detecting zero-sequence currents I01, I02 and … … I0n of the lines, and starting a fault line selection program to select a fault line m; carrying out fault total current estimation by utilizing the zero sequence current I0m at the outlet of the fault line, the system ground capacitance calculated in the normal state, the fault line capacitance and the current distortion empirical value under the fault condition to obtain the fault current If of the whole system containing the fault line grounding current, the power component and the harmonic component; and detecting the compensation current IL1 of the current main coil and the active slave arc suppression coil, wherein IL2 applies an active inversion algorithm to generate a power device driving signal to control the active slave arc suppression coil to perform full compensation. While the algorithms of the earth fault integrated protection system based on full compensation all use neutral voltage (UEN) and feeder sum current as detection criteria. The fastest algorithm for ground fault detection is initial transient detection. The fault feeder line can be immediately identified when the ground fault occurs, the detection mode is very quick and stable, in order to achieve higher fault detection level, the self-adaptive zero sequence admittance measurement is used as a second detection mode, and zero sequence admittance values are measured and compared twice before and after the arc suppression coil is put into a capacitive element. Because the scheme adopts a differential algorithm, the equipment measurement errors of CT: s and VT: s can be eliminated, and a very sensitive setting condition is provided, and the PSCAD simulation proves that the active slave arc suppression coil can optimize the compensation effect of the main coil under the fault condition of power loss and harmonic component, the residual current after compensation is reduced to a very small level, and the success rate of reliable arc extinction of the electric arc grounding fault is ensured.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.