CN117665481A

CN117665481A - Fault judging method, device, computer equipment and storage medium

Info

Publication number: CN117665481A
Application number: CN202311636084.3A
Authority: CN
Inventors: 卢正飞; 张安龙; 晋龙兴; 马帅; 周瑜; 郭乐欣; 简学之
Original assignee: Shenzhen Power Supply Bureau Co Ltd
Current assignee: Shenzhen Power Supply Bureau Co Ltd
Priority date: 2023-11-30
Filing date: 2023-11-30
Publication date: 2024-03-08

Abstract

The application relates to a fault judging method, a fault judging device, computer equipment and a storage medium. The method comprises the following steps: acquiring zero sequence current, zero sequence current phase value, three-phase voltage phase value and three-phase memory voltage phase value of a protection installation position corresponding to an inverse distributed power supply; determining fault phases and fault types in the three phases according to the three-phase voltage phase values; determining whether an outlet fault occurs on the reverse type distributed power supply side according to the fault phase, the voltage phase value corresponding to the fault and the fault type; if the outlet fault occurs, determining a fault current comparison value according to the fault type, the three-phase current phase value and the zero sequence current phase value, and determining a memory voltage comparison value according to the three-phase memory voltage phase value and the fault type; and determining the direction of the outlet fault of the inversion type distributed power supply side according to the phase value of the memory voltage comparison value and the phase value of the fault current comparison value. The fault direction can be effectively identified by adopting the method.

Description

Fault judging method, device, computer equipment and storage medium

Technical Field

The present disclosure relates to the field of power systems, and in particular, to a fault determining method, a fault determining device, a computer device, and a storage medium.

Background

With the massive grid connection of power electronic power supplies such as wind power, photovoltaic, energy storage and the like, the power electronic degree of a power system is increased. The fault characteristics of the power electronic power supply and the synchronous generator are obviously different, the characteristics of limited short-circuit current amplitude, frequency offset and the like are mainly shown, and after the power transmission line has an outlet fault, fault phase current consists of fault output current and local load current of an inversion type distributed power supply (Inverter Interfaced Distributed Generator, IIDG). The amplitude and phase of the IIDG fault output current change along with the active output before the fault and the voltage drop degree of the grid-connected point, and the phase difference between the fault current and the positive sequence voltage at the line protection installation position can change between-180 degrees and 180 degrees, so that the phase-comparison type distance protection is invalid.

The existing phase-comparison directional element adopts phase voltage polarization or positive sequence voltage polarization at a protection installation place. The directional element adopting voltage polarization at the protection installation position has good action performance, but has the problem of dead zone of protection outlet fault; with the use of a forward voltage polarized directional element at the location of the protection installation, incorrect operation may occur due to the failure characteristics of the inverter power supply, and thus, improvements are needed.

Disclosure of Invention

According to the above-mentioned technical problems, there is a need to provide a fault judging method, a device, a computer device and a storage medium capable of accurately identifying a line fault, and capable of identifying a fault direction and timely making a corresponding action.

In a first aspect, the present application provides a fault determination method, including:

acquiring zero sequence current, zero sequence current phase value, three-phase voltage phase value and three-phase memory voltage phase value of a protection installation position corresponding to an inverse distributed power supply;

determining fault phases and fault types in the three phases according to the three-phase voltage phase values;

determining whether an outlet fault occurs on the reverse type distributed power supply side according to the fault phase, the voltage phase value corresponding to the fault and the fault type;

if the outlet fault occurs, determining a fault current comparison value according to the fault type, the three-phase current phase value and the zero sequence current phase value, and determining a memory voltage comparison value according to the three-phase memory voltage phase value and the fault type;

and determining the direction of the outlet fault of the inversion type distributed power supply side according to the phase value of the memory voltage comparison value and the phase value of the fault current comparison value.

In one embodiment, obtaining a zero sequence current, a zero sequence current phasor value, a three-phase voltage phasor value, and a three-phase remembered voltage phasor value at a protection installation location corresponding to an inverter type distributed power source includes:

acquiring a real-time current sequence and a real-time voltage sequence of a protection installation position corresponding to an inverse distributed power supply; determining zero sequence current according to the real-time current sequence and the real-time voltage sequence; determining a zero sequence current phasor value according to the zero sequence current; determining three-phase current phasor values according to the real-time current sequence; determining three-phase voltage phasor values according to the real-time voltage sequence; according to the real-time voltage sequence, the three phases memorize the voltage phasor values.

In one embodiment, determining a direction in which an outlet fault occurs on the inverter-type distributed power source side based on the phase value of the stored voltage comparison value and the phase value of the fault current comparison value includes:

if the ratio between the phase value of the memory voltage comparison value and the phase value of the fault current comparison value falls into a first threshold value interval and the protection device corresponding to the protection installation position is in an unprotected locking state, determining that the direction of the outlet fault of the inversion type distributed power supply side is a forward outlet fault.

In one embodiment, the first threshold interval is [ -45 °,135 ° ].

In one embodiment, the fault types include single phase earth faults, two phase faults, and three phase short circuit faults.

In one embodiment, determining the fault current comparison value based on the fault type, the three-phase current phase value, and the zero-sequence current phase value comprises:

if the fault type is single-phase ground fault, determining a fault current comparison value according to the current phase value of the fault phase; if the fault type is any one of a two-phase ground fault, a two-phase fault and a three-phase short circuit fault, the fault current comparison value is determined according to the phase-to-phase current phasor value of the fault.

In one embodiment, determining the memory voltage comparison value based on the three-phase memory voltage phasor value and the fault type comprises:

if the fault type is single-phase earth fault, determining a memorizing voltage comparison value according to a memorizing voltage phasor value of a fault phase; if the fault type is any one of two-phase grounding fault, two-phase fault and three-phase short circuit fault, the memory voltage comparison value is determined according to the interphase memory voltage phasor value with fault.

In one embodiment, determining whether an outlet fault occurs on the inverted distributed power supply side according to the fault phase, the voltage phase value corresponding to the fault, and the fault type includes:

determining a fault voltage comparison value according to the fault type and the three-phase voltage phasor value; if the fault voltage comparison value is smaller than the voltage threshold, determining that the inversion type distributed power supply side has an outlet fault.

In one embodiment, determining the fault voltage comparison value based on the fault type and the three-phase voltage phasor values comprises:

if the fault type is single-phase ground fault, the fault voltage comparison value is the absolute value of the fault phase voltage phase value; if the fault type is any one of two-phase grounding fault, two-phase fault and three-phase short circuit fault, the fault voltage comparison value is the absolute value of the phase-to-phase voltage phasor value with faultMultiple times.

In one embodiment, the method further comprises:

determining that the inversion type distributed power supply side has no outlet fault, and determining compensation voltage and polarization voltage according to the three-phase current phasor value and the fault current comparison value; and determining whether the inversion type distributed power supply side has an intra-area fault or an external-area fault according to the compensation voltage and the polarization voltage.

In a second aspect, the present application further provides a fault determining apparatus, including:

the acquisition module is used for acquiring zero sequence current, zero sequence current phasor value, three-phase voltage phasor value and three-phase memory voltage phasor value of the protection installation position corresponding to the inversion type distributed power supply;

the first determining module is used for determining fault phases and fault types in three phases according to the three-phase voltage phasor values;

the second determining module is used for determining whether the inversion type distributed power supply side has an outlet fault or not according to the fault phase, the voltage phase value corresponding to the fault and the fault type;

the third determining module is used for determining a fault current comparison value according to the fault type, the three-phase current phase value and the zero sequence current phase value if the outlet fault occurs, and determining a memory voltage comparison value according to the three-phase memory voltage phase value and the fault type;

and the fourth determining module is used for determining the direction of the outlet fault of the inversion type distributed power supply side according to the phase value of the memory voltage comparison value and the phase value of the fault current comparison value.

In a third aspect, the present application also provides a computer device comprising a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program:

In a fourth aspect, the present application also provides a computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of:

In a fifth aspect, the present application also provides a computer program product comprising a computer program which, when executed by a processor, performs the steps of:

According to the fault judging method, the device, the computer equipment and the storage medium, the renewable energy source is fully considered to be influenced by the fault ride-through control strategy, the characteristics that the power supply impedance changes and the fault current possibly show frequency deviation and the like are shown in the fault process, and the phase relation between the memory voltage and the fault current at the protection installation position is utilized, so that the forward outlet fault and the reverse outlet fault of the alternating current circuit are effectively distinguished. According to the scheme, the phase relation between the memory voltage and the fault current at the protection installation position is analyzed, so that the protection device can act correctly when the IIDG is connected to the AC line of the power grid to generate faults, is not influenced by the fault position and the fault type, and has good protection performance.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for a person having ordinary skill in the art.

Fig. 1 is a schematic diagram of a fault of a high-voltage line of an IIDG access power system provided in an embodiment of the present application;

fig. 2 is a flow chart of a fault determining method provided in an embodiment of the present application;

FIG. 3 is a schematic flow chart of determining whether an outlet failure occurs on the reverse-type distributed power supply side according to an embodiment of the present application;

FIG. 4 is a schematic flow chart of further fault determination when no exit fault occurs according to an embodiment of the present application;

FIG. 5 is a flow chart of another fault determination method according to an embodiment of the present disclosure;

fig. 6 is a block diagram of a fault determining apparatus according to an embodiment of the present application;

FIG. 7 is a block diagram of another fault determination device according to an embodiment of the present application;

fig. 8 is an internal structural diagram of a computer device provided in an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

With the increasing degree of power electronization of a power system, the difference of fault characteristics of a power electronic power supply and a synchronous generator is more and more obvious, the characteristics of limited short-circuit current amplitude, frequency offset and the like are mainly shown, and after an outlet fault occurs to a power transmission line, fault phase current consists of IIDG fault output current and local load current. However, when the IIDG side has outlet faults, the phase difference between the fault current and the positive sequence voltage at the line protection installation position can be changed between-180 degrees and 180 degrees, and the phase-comparison type distance protection is invalid.

The existing phase-comparison directional element adopts phase voltage polarization or positive sequence voltage polarization at a protection installation place. The directional element adopting voltage polarization at the protection installation position has good action performance, but has the problem of dead zone of protection outlet fault; with the use of the forward voltage polarized directional element at the protection installation site, incorrect operation may occur due to the influence of the fault characteristics of the inverter power supply.

Based on this, in order to accurately detect the fault problem on the IIDG side and accurately determine the fault direction, the embodiment of the application provides a fault determination method. Fig. 1 provides an application environment to which the method is applicable. In fig. 1, the IIDG100 is connected to the power system 400, protection devices are installed on both sides of the IIDG100 and the power system 400, the protection installation place 200 monitors and protects the IIDG100 side, the protection installation place 400 monitors and protects the power system 400 side, the detection devices installed at the protection installation place 200 and the protection installation place 400 can monitor information such as voltage and current of a circuit in real time, when an abnormal circuit condition is detected, related protection measures are immediately started, a fault circuit is cut off, electrical equipment of the power system is protected from further damage, and meanwhile reliable operation of the power system is guaranteed. Wherein the voltage information includes, but is not limited to, three-phase voltages and interphase voltages, wherein the three-phase voltages specifically refer to a-phase voltage, b-phase voltage and c-phase voltage, and the interphase voltages specifically refer to ab interphase voltage, bc interphase voltage and ca interphase voltage; the current information includes, but is not limited to, three-phase current and interphase current, wherein the three-phase current specifically refers to a-phase current, b-phase current and c-phase current, and the interphase current specifically refers to ab-phase current, bc-phase current and ca-phase current; the protection installation place can be arranged in different positions of the IIDG100 and the power system 400 circuit, and is set according to the situation. The embodiment of the application mainly aims at analyzing the data information of the protection installation place 200 on the IIDG100 side.

Fig. 2 is a flow chart of a fault determining method provided in an embodiment of the present application, and the method is executed by a server as an example. As shown in fig. 2, the failure determination method includes the following S201 to S205.

Wherein:

s201, acquiring zero sequence current, zero sequence current phase value, three-phase voltage phase value and three-phase memory voltage phase value of a protection installation position corresponding to the inverse distributed power supply.

The root cause of the zero sequence current is that the line has an asymmetrical ground fault.

The three-phase current phase value and the three-phase voltage phase value are calculated based on a Fourier recurrence algorithm according to the real-time current sequence and the real-time voltage sequence; the zero sequence current can be determined through three-phase current values, and can also be acquired through a zero sequence current transformer, and the acquisition frequency can be 10kHz.

Specifically, a real-time current sequence and a real-time voltage sequence of a protection installation position corresponding to an inversion type distributed power supply are obtained; determining zero sequence current according to the real-time current sequence and the real-time voltage sequence; determining a zero sequence current phasor value according to the zero sequence current; determining three-phase current phasor values according to the real-time current sequence; determining three-phase voltage phasor values according to the real-time voltage sequence; according to the real-time voltage sequence, the three phases memorize the voltage phasor values.

The real-time current sequence and the real-time voltage sequence are obtained by carrying out the same low-pass filtering processing on the current signal and the voltage signal acquired by the detection device of the protection installation part 200 at the IIDG100 side; the low-pass filtering is a filtering mode, a frequency point is set, and when the frequency of the signal is higher than the frequency, the signal cannot pass. For example, based on the detection device installed at the protection installation site 200, a real-time current sequence and a real-time voltage sequence on the IIDG100 side, such as i _a (t)、i _b (t) and i _c (t) is the current sampling value at time t after low-pass filtering treatment, u _a (t)、u _b (t) and u _c And (t) is the voltage sampling value at the time t after the low-pass filtering treatment.

The real-time current sequence and the real-time voltage sequence are the current value and the voltage value collected from the protection installation place 200 on the IIDG100 side, and the current and the voltage at this time are affected by the fault, so that the current change characteristic and the voltage change characteristic during a certain fault can be reflected, and therefore, the fault analysis is performed by adopting the real-time current sequence and the real-time voltage sequence.

Illustratively, the real-time corresponding zero sequence current i is determined according to the real-time current sequence and the real-time voltage sequence ₀ (t)：

i ₀ (t)＝(i _a (t)+i _b (t)+i _c (t))/3 (1)

Wherein i is _a (t)、i _b (t) and i _c And (t) is a current sampling value at the time t after low-pass filtering processing.

Obtaining zero sequence current i ₀ After (t), determining the zero-sequence current phasor value according to the zero-sequence currentThe process is as follows:

wherein T is a power frequency period, N is a sampling frequency, and i is an imaginary unit.

Further, according to the real-time current sequence, determining the three-phase current phasor valueThe process is as follows:

determining three-phase voltage phasor values according to the real-time voltage sequenceThree-phase memory voltage phasor value +.>The process is as follows:

wherein,is the voltage sampling value at the time t after the low-pass filtering processing.

The memory voltage phasor value is a sampling value of each phase voltage before the fault occurs, and the fault is determined more clearly by comparing each phase voltage sequence before the fault occurs with the signal condition after the fault occurs.

S202, determining fault phases and fault types in three phases according to the three-phase voltage phase values.

Wherein the failed phase is the failed phase in the three phases; fault types include single phase earth faults, two phase faults, and three phase short circuit faults.

When a single-phase earth fault occurs, the voltage of the fault phase is reduced, the voltage of other two phases is basically unchanged or slightly increased, the characteristic point is obvious, and the frequency of the single-phase earth fault is highest, so that the single-phase earth fault is regarded as a single fault type.

Alternatively, the phase values of the three-phase voltages corresponding to different fault types may be different, so that the fault phase and the fault type may be determined according to the difference of the phase values of the three-phase voltages.

S203, determining whether the outlet fault occurs on the inverse distributed power supply side according to the fault phase, the voltage phase value corresponding to the fault and the fault type.

The outlet fault is the place where the fault occurs in the outlet area, namely the electric equipment current outlet, or the place where the relay protection device is installed.

Illustratively, when an outlet fault occurs, the fault current flowing through the protection installation 200 on the IIDG100 side is from either the IIDG100 or the power system 400; when an intra-zone or an out-of-zone fault occurs, the fault current flowing through the protection installation 200 on the IIDG100 side is from the IIDG100. Wherein, when the fault current flowing through the protection installation 200 on the IIDG100 side is from the IIDG100, the voltage-current conditions of the outlet fault, the in-zone fault, and the out-of-zone fault are also different.

The transmission line to which the IIDG100 is connected to the power system 400 is a three-phase transmission line. The part of the transmission line near the side of the IIDG100 is an outlet area, for example, the length of the outlet area of the line may be 10% of the whole transmission line; according to the protection scope of the protection device related to the protection installation place 200, the part of the transmission line connected by the IIDG100 and the power system 400 is divided into an inside area and an outside area, for example, part of the line between the protection installation place 200 and the protection installation place 300 near one side of the protection installation place 200 is inside the area, and other part of the line is outside the area.

Optionally, when determining whether the reverse-type distributed power source side has an outlet fault according to the fault phase, the voltage phase value corresponding to the fault and the fault type, the voltage comparison value U may be obtained by voltage-adjusting the corresponding voltage phase value according to the voltage phase value of the fault phase or the phase-to-phase voltage phase value having the fault _bj Comparing the voltage with the value U _bj With a preset voltage threshold U _set Comparing, and judging whether the fault of the line is an outlet fault or not according to a comparison result; further, the out-of-zone faults and the in-zone faults can be judged according to the fault phases and the voltage phase values corresponding to the faults.

S204, if an outlet fault occurs, determining a fault current comparison value according to the fault type, the three-phase current phase value and the zero-sequence current phase value, and determining a memory voltage comparison value according to the three-phase memory voltage phase value and the fault type.

The fault current comparison value is a value obtained by performing current adjustment according to a current phase value of a fault phase or an interphase current phase value with a fault. For example, if the fault type is a single-phase ground fault, the fault current comparison value is determined according to the current phase value of the fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the fault current comparison value is determined according to the phase-to-phase current phasor value with the fault.

Exemplary, if the fault type is a single phase ground fault, the fault current comparison valueThe determination process of (2) is as follows:

wherein,for the fault phase current phasor value, K is the zero sequence compensation coefficient of the protection circuit of the protection installation place 200, < ->Is the zero sequence current phasor value. If the fault type is any one of a two-phase earth fault, a two-phase fault and a three-phase short-circuit fault, the fault current comparison value +.>The determination process of (2) is as follows:

wherein,is the phase-to-phase current phasor value at which the fault occurs.

The memorizing voltage comparison value is a value obtained by performing voltage adjustment according to the memorizing voltage phasor value of the fault phase or the interphase memorizing voltage phasor value of the fault phase. For example, if the fault type is a single-phase ground fault, the stored voltage comparison value is determined from the stored voltage phasor value of the fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the memorizing voltage comparison value is determined according to the interphase memorizing voltage phasor value with the fault.

Exemplary, if the fault type is a single phase ground fault, the voltage comparison value is memorizedThe determination process of (2) is as follows:

wherein,a remembered voltage phasor value for the failed phase. If the fault type is any one of two-phase earth fault, two-phase fault and three-phase short circuit fault, the comparison value of voltage is memorized +. >The determination process of (2) is as follows:

wherein,the voltage phasor values are memorized for the failed interphase.

S205, determining the direction of the outlet fault of the inversion type distributed power supply side according to the phase value of the memory voltage comparison value and the phase value of the fault current comparison value.

The outlet fault direction is divided into a forward fault and a reverse fault.

For example, when the fault point is located on the IIDG100 side of the protection installation site 200, that is, the fault point is located on a line between the protection installation site 200 and the IIDG100, it is determined that the fault direction of the fault point with respect to the protection installation site 200 is a reverse fault; when the fault point is located on the conventional power system side of the protection installation site 200, i.e., the fault point is located on the line between the protection installation site 200 and the power system 400, it is explained that the fault point is a positive fault with respect to the fault direction of the protection installation site 200.

The phase difference is calculated by phase between the memorized voltage comparison value (voltage of each phase before failure) and the fault current comparison value (current of each phase after failure) to obtain the impedance angle of the line, and the direction and position of the failure are determined according to the impedance angle, thereby determining the direction of the outlet failure.

According to the fault judging method, the renewable energy source is fully considered to be influenced by the fault ride-through control strategy, the characteristics that the power supply impedance changes and the fault current possibly show frequency deviation and the like are shown in the fault process, and the phase relation between the memory voltage and the fault current at the protection installation position is utilized, so that the forward outlet fault and the reverse outlet fault of the alternating current circuit are effectively distinguished. According to the scheme, the phase relation between the memory voltage and the fault current at the protection installation position is analyzed, so that the protection device can act correctly when the IIDG is connected to the AC line of the power grid to generate faults, is not influenced by the fault position and the fault type, and has good protection performance.

In an exemplary embodiment, if the ratio between the phase value of the memory voltage comparison value and the phase value of the fault current comparison value falls within a first threshold interval and the protection device corresponding to the protection installation position is in a non-protection locking state, determining that the direction of the outlet fault of the inverter type distributed power source side is a forward outlet fault; wherein the first threshold interval is [ -45 °,135 ° ].

Alternatively, if it meetsAnd continuously maintaining at three sampling points, judging that a forward outlet fault occurs without protection locking at the moment, and outputting a protection action mark. Otherwise, judging that the out-of-zone fault occurs, waiting for the next fault to occur, and repeating the steps S201 to S205 when the next fault occurs.

In an exemplary embodiment, the embodiment of the present application explains the above embodiment S203 in detail. Specifically, the embodiment of the present application relates to a process for determining whether an outlet fault occurs on the inverter-type distributed power source side, as shown in fig. 3, and specifically includes the following S301 to S302. Wherein:

s301, determining a fault voltage comparison value according to the fault type and the three-phase voltage phasor value.

The fault voltage comparison value is a value obtained by performing voltage adjustment according to the voltage phase value of the fault phase or the phase-to-phase voltage phase value with the fault. For example, if the fault type is a single-phase ground fault, the fault voltage comparison value is an absolute value of a fault phase voltage phasor value; if the fault type is any one of two-phase grounding fault, two-phase fault and three-phase short circuit fault, the fault voltage comparison value is the absolute value of the phase-to-phase voltage phasor value with fault Multiple times. Fault voltage comparison value U _bj The determination of (2) can be expressed as:

wherein,voltage phase value for the faulty phase, +.>Is the phase-to-phase voltage phasor value at which the fault occurs.

S302, if the fault voltage comparison value is smaller than the voltage threshold, determining that an outlet fault occurs on the inverter type distributed power source side.

The threshold voltage is a preset value for judging whether the fault is an outlet fault threshold.

Specifically, if the voltage comparison value is smaller than the threshold voltage, U _bj <U _set Judging that the fault at the moment is an outlet fault; otherwise, other line positions fail.

It should be noted that there is a voltage thresholdThe value is determined according to the rated voltage of the system and the normal running state of the system. For example, the allowable voltage deviation of the system is not more than 10% in normal operation, and the rated voltage of the system is U _N Then there is a voltage threshold value U _set It can be set as:

U _set ＝1.1*U _N (11)

in the embodiment, by introducing the fault voltage comparison value and the voltage threshold, a foundation is laid for judging whether the outlet fault occurs.

In an exemplary embodiment, the fault determining method further provides a further fault determining method when no exit fault occurs, as shown in fig. 4, specifically including the following S401 to S402. Wherein:

And S401, determining that the inversion type distributed power supply side has no outlet fault, and determining the compensation voltage and the polarization voltage according to the three-phase current phasor value and the fault current comparison value.

Specifically, if the fault type is a single-phase ground fault, the polarization voltageFor the phase voltage phase value of the fault->Compensation voltage->By polarization voltage->Fault current comparison value->And setting impedance Z _ZD To represent; wherein, the setting principle is the same as the line distance protection; polarization voltage->And compensation voltage->The specific expression process of (2) is as follows:

wherein,z is the phase voltage phasor value of the fault _ZD To set the impedance.

If the fault type is any one of two-phase earth fault, two-phase fault and three-phase short circuit fault, polarizing voltageInterphase voltage phasor value for failure +.>Compensation voltage->By polarization voltage->Fault current comparison value->And setting impedance Z _ZD To represent; the setting principle is the same as the line distance protection. Polarization voltage->And compensation voltage->The specific expression process of (2) is as follows:

wherein,is the phase-to-phase voltage phasor value at which the fault occurs.

S402, determining whether the inverse type distributed power supply side has an intra-area fault or an external-area fault according to the compensation voltage and the polarization voltage.

Specifically, if the specific phase distance protection criterion is metAnd at the moment, no protection lock exists, faults in the occurrence area are judged, and a protection action mark is output. Otherwise, judging that the out-of-zone fault occurs, and waiting for the next fault to occur.

On the basis of the above embodiments, this embodiment provides an alternative example of a failure determination method.

As shown in fig. 5, the specific implementation procedure is as follows:

s501, acquiring zero sequence current, zero sequence current phase value, three-phase voltage phase value and three-phase memory voltage phase value of a protection installation position corresponding to the inverse distributed power supply.

The method comprises the steps of obtaining a real-time current sequence and a real-time voltage sequence of a protection installation position corresponding to an inverse distributed power supply; determining zero sequence current according to the real-time current sequence and the real-time voltage sequence; determining a zero sequence current phasor value according to the zero sequence current; determining three-phase current phasor values according to the real-time current sequence; determining three-phase voltage phasor values according to the real-time voltage sequence; according to the real-time voltage sequence, the three phases memorize the voltage phasor values.

S502, determining fault phases and fault types in three phases according to the three-phase voltage phase values.

Wherein the fault type comprises single-phase earth fault, two-phase fault and three-phase short circuit fault

S503, determining a fault voltage comparison value according to the fault type and the three-phase voltage phasor value.

Specifically, if the fault type is a single-phase ground fault, the fault voltage comparison value is an absolute value of a fault phase voltage phasor value; if the fault type is any one of two-phase grounding fault, two-phase fault and three-phase short circuit fault, the fault voltage comparison value is the absolute value of the phase-to-phase voltage phasor value with faultMultiple times.

And S504, if the fault voltage comparison value is smaller than the voltage threshold, determining that the inversion type distributed power supply side has an outlet fault.

S505, if an outlet fault occurs, determining a fault current comparison value according to the fault type, the three-phase current phase value and the zero-sequence current phase value, and determining a memorizing voltage comparison value according to the three-phase memorizing voltage phase value and the fault type.

Specifically, if the fault type is a single-phase ground fault, determining a fault current comparison value according to the current phase value of the fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the fault current comparison value is determined according to the phase-to-phase current phasor value with the fault. If the fault type is single-phase ground fault, determining a memorizing voltage comparison value according to a memorizing voltage phasor value of a fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the memorizing voltage comparison value is determined according to the interphase memorizing voltage phasor value with the fault.

S506, if the ratio between the phase value of the memory voltage comparison value and the phase value of the fault current comparison value falls into a first threshold value interval and the protection device corresponding to the protection installation position is in a non-protection locking state, determining that the direction of the outlet fault of the inversion type distributed power supply side is a forward outlet fault.

Wherein the first threshold interval is [ -45 °,135 ° ].

And S507, if no outlet fault occurs at the side of the inversion type distributed power supply, determining the compensation voltage and the polarization voltage according to the three-phase current phasor value and the fault current comparison value.

S508, determining whether the reverse type distributed power supply side has an in-region fault or an out-of-region fault according to the compensation voltage and the polarization voltage.

The specific process of S501-S508 may refer to the description of the foregoing method embodiment, and its implementation principle and technical effects are similar, and are not repeated herein.

It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.

Based on the same inventive concept, the embodiment of the application also provides a fault judging device for realizing the fault judging method. The implementation of the solution provided by the device is similar to the implementation described in the above method, so the specific limitation in one or more embodiments of the fault determining device provided below may refer to the limitation of the fault determining method hereinabove, and will not be repeated herein.

In an exemplary embodiment, as shown in fig. 6, there is provided a failure judgment apparatus 1 including: the acquisition module 10, the first determination module 20, the second determination module 30, the third determination module 40 and the fourth determination module 50, wherein:

the acquisition module 10 is configured to acquire a zero sequence current, a zero sequence current phase value, a three-phase voltage phase value and a three-phase memory voltage phase value at a protection installation position corresponding to the inverse distributed power supply.

A first determining module 20, configured to determine a fault phase and a fault type in the three phases according to the three-phase voltage phase values;

the second determining module 30 determines whether an outlet fault occurs on the inverse type distributed power source side according to the fault phase, the voltage phase value corresponding to the fault, and the fault type.

The third determining module 40 is configured to determine a fault current comparison value according to the fault type, the three-phase current phase value and the zero-sequence current phase value, and determine a memorizing voltage comparison value according to the three-phase memorizing voltage phase value and the fault type if the exit fault occurs.

And a fourth determining module 50, configured to determine a direction in which the outlet fault occurs on the inverter-type distributed power source side according to the phase value of the stored voltage comparison value and the phase value of the fault current comparison value.

In one embodiment, the acquisition module 10 is specifically configured to:

In one embodiment, the first determination module 20 includes:

fault types include single phase earth faults, two phase faults, and three phase short circuit faults.

In one embodiment, as shown in fig. 7, the second determining module 30 includes:

The first determination unit 31: the fault voltage comparison value is determined according to the fault type and the three-phase voltage phasor value;

the second determination unit 32: and if the fault voltage comparison value is smaller than the voltage threshold, determining that the inversion type distributed power supply side has an outlet fault.

In one embodiment, the first determining unit 31 is specifically configured to:

In one embodiment, the third determining module 40 is specifically configured to:

if the fault type is single-phase earth fault, determining a fault current comparison value according to the current phase value of the fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the fault current comparison value is determined according to the phase-to-phase current phasor value with the fault. If the fault type is single-phase ground fault, determining a memorizing voltage comparison value according to a memorizing voltage phasor value of a fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the memorizing voltage comparison value is determined according to the interphase memorizing voltage phasor value with the fault.

In one embodiment, the fourth determination module 50 is specifically configured to:

if the ratio between the phase value of the memory voltage comparison value and the phase value of the fault current comparison value falls into a first threshold value interval and the protection device corresponding to the protection installation position is in an unprotected locking state, determining that the direction of the outlet fault of the inversion type distributed power supply side is a forward outlet fault. Wherein the first threshold interval is [ -45 °,135 ° ].

In one embodiment, the fault determining apparatus 1 specifically further includes:

The respective modules in the above-described failure determination apparatus may be implemented in whole or in part by software, hardware, and combinations thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.

In one exemplary embodiment, a computer device is provided, which may be a server, and the internal structure thereof may be as shown in fig. 8. The computer device includes a processor, a memory, an Input/Output interface (I/O) and a communication interface. The processor, the memory and the input/output interface are connected through a system bus, and the communication interface is connected to the system bus through the input/output interface. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database of the computer device is used to store test data. The input/output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used for communicating with an external terminal through a network connection. The computer program, when executed by a processor, implements a fault determination method.

It will be appreciated by those skilled in the art that the structure shown in fig. 8 is merely a block diagram of some of the structures associated with the present application and is not limiting of the computer device to which the present application may be applied, and that a particular computer device may include more or fewer components than shown, or may combine certain components, or have a different arrangement of components.

In one exemplary embodiment, a computer device is provided comprising a memory and a processor, the memory having stored therein a computer program, the processor when executing the computer program performing the steps of:

In one embodiment, the processor when executing the computer program further performs the steps of:

The first threshold interval is [ -45 °,135 ° ].

if the fault type is single-phase earth fault, determining a fault current comparison value according to the current phase value of the fault phase; if the fault type is any one of a two-phase ground fault, a two-phase fault and a three-phase short circuit fault, the fault current comparison value is determined according to the phase-to-phase current phasor value of the fault.

if the fault type is single-phase earth fault, the faultThe voltage comparison value is the absolute value of the fault phase voltage phasor value; if the fault type is any one of two-phase grounding fault, two-phase fault and three-phase short circuit fault, the fault voltage comparison value is the absolute value of the phase-to-phase voltage phasor value with faultMultiple times.

In one embodiment, a computer readable storage medium is provided having a computer program stored thereon, which when executed by a processor, performs the steps of:

In one embodiment, the computer program when executed by the processor further performs the steps of:

the first threshold interval is [ -45 °,135 ° ].

if the fault type is single-phase earth fault, determining a fault current comparison value according to the current phase value of the fault phase; if the fault type is any one of a two-phase grounding fault, a two-phase fault and a three-phase short circuit fault, the fault current comparison value is determined according to the phase-to-phase current phasor value with the fault.

In one embodiment, a computer program product is provided comprising a computer program which, when executed by a processor, performs the steps of:

the first threshold interval is [ -45 °,135 ° ].

Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in the various embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high density embedded nonvolatile Memory, resistive random access Memory (ReRAM), magnetic random access Memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric Memory (Ferroelectric Random Access Memory, FRAM), phase change Memory (Phase Change Memory, PCM), graphene Memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in the form of a variety of forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), and the like. The databases referred to in the various embodiments provided herein may include at least one of relational databases and non-relational databases. The non-relational database may include a distributed database according to a blockchain, etc., without being limited thereto. The processors referred to in the embodiments provided herein may be general-purpose processors, central processing units, graphics processors, digital signal processors, programmable logic, data processing logic based on quantum computing, etc., without being limited thereto.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application shall be subject to the appended claims.

Claims

1. A fault determination method, the method comprising:

determining fault phases and fault types in three phases according to the three-phase voltage phase values;

Determining whether an outlet fault occurs on the inverter type distributed power source side according to the fault phase, the voltage phasor value corresponding to the fault and the fault type;

2. The method of claim 1, wherein obtaining the zero sequence current, the zero sequence current phasor value, the three phase voltage phasor value, and the three phase remembered voltage phasor value at the protection installation corresponding to the inverted distributed power source comprises:

acquiring a real-time current sequence and a real-time voltage sequence of a protection installation position corresponding to an inverse distributed power supply;

determining a zero sequence current according to the real-time current sequence and the real-time voltage sequence;

determining a zero sequence current phasor value according to the zero sequence current;

determining three-phase current phasor values according to the real-time current sequence;

Determining a three-phase voltage phasor value according to the real-time voltage sequence;

and according to the real-time voltage sequence, memorizing the voltage phasor values of the three phases.

3. The method according to claim 1, wherein the determining the direction of the outlet fault of the inverter-type distributed power source side based on the phase value of the memorized voltage comparison value and the phase value of the fault current comparison value includes:

if the ratio between the phase value of the memory voltage comparison value and the phase value of the fault current comparison value falls into a first threshold value interval and the protection device corresponding to the protection installation position is in a non-protection locking state, determining that the direction of the outlet fault of the inversion type distributed power supply side is a forward outlet fault.

4. A method according to claim 3, wherein the first threshold interval is [ -45 °,135 ° ].

5. The method of claim 1, wherein the fault types include single phase earth faults, two phase faults, and three phase short faults.

6. The method of claim 5, wherein determining a fault current comparison value based on the fault type, three-phase current phasor value, and zero-sequence current phasor value comprises:

If the fault type is the single-phase earth fault, determining a fault current comparison value according to the current phase value of the fault phase;

if the fault type is any one of the two-phase earth fault, the two-phase fault and the three-phase short circuit fault, determining a fault current comparison value according to the interphase current phasor value with the fault.

7. The method of claim 5, wherein determining the remembered voltage comparison value based on the three-phase remembered voltage phasor value and the fault type comprises:

if the fault type is the single-phase earth fault, determining a memorizing voltage comparison value according to a memorizing voltage phasor value of a fault phase;

and if the fault type is any one of the two-phase grounding fault, the two-phase fault and the three-phase short circuit fault, determining a memorizing voltage comparison value according to the interphase memorizing voltage phasor value with the fault.

8. The method of claim 5, wherein determining whether an outlet fault has occurred on the inverted distributed power supply side based on the faulty phase, the voltage phase value corresponding to the fault, and the fault type comprises:

determining a fault voltage comparison value according to the fault type and the three-phase voltage phasor value;

And if the fault voltage comparison value is smaller than the voltage threshold, determining that the inversion type distributed power supply side has an outlet fault.

9. The method of claim 8, wherein said determining a fault voltage comparison value based on said fault type and a three-phase voltage phasor value comprises:

if the fault type is single-phase grounding fault, the fault voltage comparison value is the absolute value of the fault phase voltage phase value;

if the fault type is any one of the two-phase earth fault, the two-phase fault and the three-phase short circuit fault, the fault voltage comparison value is the absolute value of the phase-to-phase voltage phasor value with faultMultiple times.

10. The method according to claim 1, wherein the method further comprises:

determining that no outlet fault occurs on the reverse type distributed power supply side, and determining a compensation voltage and a polarization voltage according to the three-phase current phasor value and the fault current comparison value;

and determining whether the reverse type distributed power supply side has an intra-area fault or an external-area fault according to the compensation voltage and the polarization voltage.

11. A fault determination apparatus, the apparatus comprising:

12. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any one of claims 1 to 10 when the computer program is executed.

13. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 10.

14. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any one of claims 1 to 10.