CN109975662B - Phase selection method and device for photovoltaic power station to access power grid - Google Patents

Phase selection method and device for photovoltaic power station to access power grid Download PDF

Info

Publication number
CN109975662B
CN109975662B CN201910339165.4A CN201910339165A CN109975662B CN 109975662 B CN109975662 B CN 109975662B CN 201910339165 A CN201910339165 A CN 201910339165A CN 109975662 B CN109975662 B CN 109975662B
Authority
CN
China
Prior art keywords
phase
voltage
fault
degrees
phase voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910339165.4A
Other languages
Chinese (zh)
Other versions
CN109975662A (en
Inventor
陈桥平
李一泉
屠卿瑞
刘玮
焦邵麟
张智锐
王峰
吴梓亮
邓旭阳
杜斌
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangdong Power Grid Co Ltd
Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd
Original Assignee
Guangdong Power Grid Co Ltd
Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangdong Power Grid Co Ltd, Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd filed Critical Guangdong Power Grid Co Ltd
Priority to CN201910339165.4A priority Critical patent/CN109975662B/en
Publication of CN109975662A publication Critical patent/CN109975662A/en
Application granted granted Critical
Publication of CN109975662B publication Critical patent/CN109975662B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Photovoltaic Devices (AREA)

Abstract

The invention discloses a phase selection method, a phase selection device, phase selection equipment and a computer readable storage medium for a photovoltaic power station to be accessed into a power grid, wherein the method comprises the following steps: respectively acquiring three-phase voltages before and during fault and interphase voltages before and during fault of protection installation at the side of the photovoltaic power station; obtaining a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage by using the three-phase voltage, and obtaining an interphase voltage break variable by using the interphase voltage; judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not; if so, determining the fault type through the phase relation, the negative sequence fault voltage component and the zero sequence fault voltage component; if not, determining the fault type according to the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero-sequence fault voltage component. According to the technical scheme, the fault type of the alternating current line connected with the photovoltaic power station can be accurately identified through the voltage condition of the side protection installation position of the photovoltaic power station.

Description

Phase selection method and device for photovoltaic power station to access power grid
Technical Field
The invention relates to the technical field of power system relay protection, in particular to a phase selection method, a phase selection device, phase selection equipment and a computer readable storage medium for a photovoltaic power station to be connected into a power grid.
Background
With the continuous promotion of photovoltaic power generation technology, the installed capacity of a photovoltaic power station is gradually enlarged, and the permeability of the photovoltaic power station in a power grid is also continuously improved. Unlike traditional synchronous power grids based on synchronous generators, the fault current output by a photovoltaic power station is related to many factors such as a power reference value, a fault type, a control target and the overcurrent capacity of power electronic devices.
At present, a phase selection element in an existing power grid is designed based on traditional ac line fault characteristics, and the phase selection element is a core element of distance protection and automatic reclosing, so that the phase selection element is required to correctly identify a fault phase in order to ensure that the power grid can safely and stably operate. However, after the photovoltaic power station is connected to the power grid, the fault current characteristics of an ac line connected to the photovoltaic power station may be changed, that is, the difference between the fault current characteristics and the fault current characteristics of an ac line of a conventional synchronous power grid is relatively large due to the connection of the photovoltaic power station, so that the phase current difference sudden change phase selection element and the current sequence component phase selection element designed based on the fault current characteristics of the conventional ac line have adaptability problems, that is, the phase selection element in the conventional power grid cannot correctly identify the fault type of the ac circuit connected to the photovoltaic power station, and the failure of the phase selection element to correctly identify the fault type may cause incorrect actions of distance protection and automatic reclosing, which may finally threaten the safe and stable operation of the power grid.
In summary, how to accurately identify the fault type of the ac line connected to the photovoltaic power station to ensure that the power grid can operate safely and stably is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a phase selection method, apparatus, device and computer readable storage medium for accessing a photovoltaic power station to a power grid, so as to accurately identify a fault type of an ac line connected to the photovoltaic power station, thereby ensuring that the power grid can operate safely and stably.
In order to achieve the above purpose, the invention provides the following technical scheme:
a phase selection method for a photovoltaic power station to be connected into a power grid comprises the following steps:
respectively acquiring three-phase voltages before and during fault and interphase voltages before and during fault of protection installation at the side of the photovoltaic power station;
obtaining a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage by using the three-phase voltage, and obtaining an interphase voltage break variable by using the interphase voltage;
obtaining a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase A and the rated voltage amplitude of the phase A before the fault, and judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not;
if so, obtaining a phase relation through a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage, and determining a fault type through the phase relation, the negative sequence fault voltage component and the zero sequence fault voltage component;
if not, obtaining a phase voltage amplitude relation through the phase voltage abrupt change, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt change, and determining a fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero-sequence fault voltage component.
Preferably, the obtaining of the phase voltage break variable and the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the a-phase voltage by using the three-phase voltage and the obtaining of the phase-to-phase voltage break variable by using the phase-to-phase voltage include:
using the A-phase voltage at fault
Figure BDA0002040140920000021
B phase voltage
Figure BDA0002040140920000022
C phase voltage
Figure BDA0002040140920000023
And a-phase voltage before fault
Figure BDA0002040140920000024
B phase voltage
Figure BDA0002040140920000025
C phase voltage
Figure BDA0002040140920000026
According to
Figure BDA0002040140920000027
Respectively calculating the voltage abrupt change of phase A
Figure BDA0002040140920000028
Abrupt change of phase voltage of phase B
Figure BDA0002040140920000029
C phase voltage abrupt change amount
Figure BDA00020401409200000210
Wherein M is a protection installation position at the side of the photovoltaic power station;
according to
Figure BDA00020401409200000211
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure BDA00020401409200000212
A-phase voltage positive sequence component before fault
Figure BDA00020401409200000213
Negative sequence component of A phase voltage in fault
Figure BDA00020401409200000214
Zero sequence component of A phase voltage in fault
Figure BDA0002040140920000031
And according to
Figure BDA0002040140920000032
Obtaining the positive sequence fault voltage component of A phase voltage
Figure BDA0002040140920000033
According to
Figure BDA0002040140920000034
Obtaining the negative sequence fault voltage component of A phase voltage
Figure BDA0002040140920000035
According to
Figure BDA0002040140920000036
Obtaining the zero-sequence fault voltage component of A-phase voltage
Figure BDA0002040140920000037
Wherein α ═ ej120°；
Using AB-phase voltage at fault
Figure BDA0002040140920000038
Phase voltage of BC phase
Figure BDA0002040140920000039
Phase voltage of CA phase
Figure BDA00020401409200000310
And AB phase voltage before failure
Figure BDA00020401409200000311
Phase voltage of BC phase
Figure BDA00020401409200000312
Phase voltage of CA phase
Figure BDA00020401409200000313
According to
Figure BDA00020401409200000314
Respectively calculating AB phase voltage abrupt change components
Figure BDA00020401409200000315
BC phase voltage abrupt component
Figure BDA00020401409200000316
Abrupt change component of phase voltage of CA phase
Figure BDA00020401409200000317
Preferably, obtaining a phase relationship through the positive sequence fault voltage component, the negative sequence fault voltage component, and the zero sequence fault voltage component of the a-phase voltage, and determining the fault type through the phase relationship, the negative sequence fault voltage component, and the zero sequence fault voltage component includes:
by using
Figure BDA00020401409200000318
Respectively calculating gamma and beta, wherein arg () represents the argument of the phasor;
judgment of
Figure BDA00020401409200000319
Whether it is equal to 0, where | represents the magnitude of the voltage phasor;
if it is
Figure BDA00020401409200000320
Equal to 0, then judge
Figure BDA00020401409200000321
Whether or not it is equal to 0, if
Figure BDA00020401409200000322
Equal to 0, the three-phase short-circuit fault is judged, if so, the three-phase short-circuit fault is detected
Figure BDA00020401409200000323
If not, judging the interval of beta: if the beta is more than or equal to-120 degrees and less than 0 degree, determining that the AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if the beta is more than or equal to 0 degrees and less than 120 degrees, the CA interphase short circuit is judged;
if it is
Figure BDA00020401409200000324
Not equal to 0, the fault type is determined by γ and β: if gamma belongs to (-30 degrees, 30 degrees) and belongs to 0(-60 degrees, 60 degrees), determining that the phase A is grounded; if gamma is belonged to 1(90 degrees, 150 degrees) and is belonged to 2(-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma belongs to (-30 degrees, 90 degrees) and beta belongs to (120 degrees, 240 degrees), judging that the BC phase grounding fault exists; if γ ∈ (90 °, 210 °) and β ∈ (0 °, 120 °), it is determined that CA has a ground fault.
Preferably, the obtaining of the phase voltage amplitude relationship through the phase voltage abrupt change, the obtaining of the phase voltage abrupt change amplitude relationship through the phase voltage abrupt change, and the determining of the fault type through the phase voltage amplitude relationship, the phase voltage amplitude relationship and the zero-sequence fault voltage component include:
by using
Figure BDA00020401409200000325
Respectively calculate m1、m2、m3、n1、n2、n3；
Judgment of
Figure BDA00020401409200000326
Whether it is equal to 0, where it represents the magnitude of the voltage phasor;
if it is
Figure BDA0002040140920000041
If n is equal to 0, then n is judged2And n3Whether or not (n) is satisfied2>z)&(1/n3>z), if yes, determining the AB interphase short circuit fault; judging n3And n1Whether or not (n) is satisfied3>z)&(1/n1>z), if yes, determining BC interphase short circuit; judging n1And n2Whether or not (n) is satisfied1>z)&(1/n2>z), if yes, determining that the CA interphase short circuit exists; if n is1、n2、n3Are all (n)2>z)&(1/n3>z)、(n3>z)&(1/n1>z)、(n1>z)&(1/n2>z), judging the three-phase short circuit fault, wherein z is 4-8;
if it is
Figure BDA0002040140920000042
If not equal to 0, m is judged1And m2Whether or not (m) is satisfied1>z)&(1/m2>z), if yes, determining that the phase A is grounded; judgment m2And m3Whether or not (m) is satisfied2>z)&(1/m3>z), if yes, judging that the B phase grounding fault exists; judgment m1And m3Whether or not (m) is satisfied3>z)&(1/m1>z), if yes, judging that the C-phase grounding fault exists;
if m1、m2、m3Are all unsatisfied (m)1>z)&(1/m2>z)、(m2>z)&(1/m3>z)、(m3>z)&(1/m1>z), judging two-phase ground fault, wherein two phases in the two-phase ground fault are
Figure BDA0002040140920000043
Two phases with larger amplitude.
Preferably, the preset threshold is any one of [0.8,0.9 ].
A phase selection device for a photovoltaic power station to be connected into a power grid comprises:
the acquisition module is used for respectively acquiring three-phase voltages of the protection installation position on the side of the photovoltaic power station before and during the fault and interphase voltages before and during the fault;
the calculation module is used for obtaining a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage by using the three-phase voltage, and obtaining an interphase voltage break variable by using the interphase voltage;
the judging module is used for obtaining a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase A and the rated voltage amplitude of the phase A before the fault, and judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not;
the first determining module is used for obtaining a phase relationship through the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage and determining a fault type through the phase relationship, the negative sequence fault voltage component and the zero sequence fault voltage component when the judging module judges that the A-phase voltage is positive;
and the second determining module is used for obtaining a phase voltage amplitude relation through the phase voltage abrupt change if the judging module judges that the fault type is not the zero sequence fault voltage component, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt change, and determining the fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero sequence fault voltage component.
Preferably, the calculation module includes:
a first calculating unit for using the A phase voltage at fault
Figure BDA0002040140920000051
B phase voltage
Figure BDA0002040140920000052
C phase voltage
Figure BDA0002040140920000053
And a-phase voltage before fault
Figure BDA0002040140920000054
B phase voltage
Figure BDA0002040140920000055
C phase voltage
Figure BDA0002040140920000056
According to
Figure BDA0002040140920000057
Respectively calculating the voltage abrupt change of phase A
Figure BDA0002040140920000058
Abrupt change of phase voltage of phase B
Figure BDA0002040140920000059
C phase voltage abrupt change amount
Figure BDA00020401409200000510
Wherein M is a protection installation position at the side of the photovoltaic power station;
a second calculation unit for calculating based on
Figure BDA00020401409200000511
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure BDA00020401409200000512
A-phase voltage positive sequence component before fault
Figure BDA00020401409200000513
Negative sequence component of A phase voltage in fault
Figure BDA00020401409200000514
Zero sequence component of A phase voltage in fault
Figure BDA00020401409200000515
And according to
Figure BDA00020401409200000516
Obtaining the positive sequence fault voltage component of A phase voltage
Figure BDA00020401409200000517
According to
Figure BDA00020401409200000518
Obtaining the negative sequence fault voltage component of A phase voltage
Figure BDA00020401409200000519
According to
Figure BDA00020401409200000520
Obtaining the zero-sequence fault voltage component of A-phase voltage
Figure BDA00020401409200000521
Wherein α ═ ej120°；
A third calculating unit for using the AB phase voltage at the time of failure
Figure BDA00020401409200000522
Phase voltage of BC phase
Figure BDA00020401409200000523
Phase voltage of CA phase
Figure BDA00020401409200000524
And AB phase voltage before failure
Figure BDA00020401409200000525
Phase voltage of BC phase
Figure BDA00020401409200000526
Phase voltage of CA phase
Figure BDA00020401409200000527
According to
Figure BDA00020401409200000528
Respectively calculating AB phase voltage abrupt change components
Figure BDA00020401409200000529
BC phase voltage abrupt component
Figure BDA00020401409200000530
Abrupt change component of phase voltage of CA phase
Figure BDA00020401409200000531
Preferably, the first determining module includes:
a fourth calculation unit for utilizing
Figure BDA00020401409200000532
Respectively calculating gamma and beta, wherein arg () represents the argument of the phasor;
a first judgment unit for judging
Figure BDA00020401409200000533
Whether it is equal to 0, where | represents the magnitude of the voltage phasor;
a first determination unit for determining if
Figure BDA00020401409200000534
Equal to 0, then judge
Figure BDA00020401409200000535
Whether or not it is equal to 0, if
Figure BDA00020401409200000536
Equal to 0, the three-phase short-circuit fault is judged, if so, the three-phase short-circuit fault is detected
Figure BDA00020401409200000537
If not, judging the interval of beta: if the beta is more than or equal to-120 degrees and less than 0 degree, determining that the AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if the beta is more than or equal to 0 degrees and less than 120 degrees, the CA interphase short circuit is judged;
a second determination unit for determining if
Figure BDA00020401409200000538
Not equal to 0, the fault type is determined by γ and β: if gamma belongs to (-30 degrees, 30 degrees) and belongs to 0(-60 degrees, 60 degrees), determining that the phase A is grounded; if gamma is belonged to 1(90 degrees, 150 degrees) and is belonged to 2(-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma belongs to (-30 degrees, 90 degrees) and beta belongs to (120 degrees, 240 degrees), judging that the BC phase grounding fault exists; if γ ∈ (90 °, 210 °) and β ∈ (0 °, 120 °), it is determined that CA has a ground fault.
A phase selection device for a photovoltaic power station to be connected into a power grid comprises:
a memory for storing a computer program;
a processor for implementing the steps of the phase selection method of the photovoltaic power plant into the grid as described in any one of the above when executing the computer program.
A computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the phase selection method of a photovoltaic power plant access grid according to any one of the preceding claims.
The invention provides a phase selection method, a phase selection device, phase selection equipment and a computer readable storage medium for a photovoltaic power station to be accessed into a power grid, wherein the method comprises the following steps: respectively acquiring three-phase voltages before and during fault and interphase voltages before and during fault of protection installation at the side of the photovoltaic power station; obtaining a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage by using the three-phase voltage, and obtaining an interphase voltage break variable by using the interphase voltage; obtaining a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase A and the rated voltage amplitude of the phase A before the fault, and judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not; if yes, obtaining a phase relation through a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage, and determining a fault type through the phase relation, the negative sequence fault voltage component and the zero sequence fault voltage component; if not, obtaining a phase voltage amplitude relation through the phase voltage abrupt change, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt change, and determining the fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero-sequence fault voltage component.
According to the technical scheme, the three-phase voltage of the photovoltaic power station side before and during the fault is obtained, the phase voltage of the protection installation before and during the fault is obtained, the three-phase voltage and the phase voltage are used for obtaining the phase voltage break variable, the phase voltage break variable and the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage, the calculated positive sequence voltage drop coefficient is compared with the preset threshold value, when the positive sequence voltage drop coefficient is larger than or equal to the preset threshold value, the fault type is judged according to the phase relation of the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage and the negative sequence fault voltage component and the zero sequence fault voltage component, and when the positive sequence voltage drop coefficient is smaller than or equal to the preset value, the fault type is judged according to the phase voltage amplitude relation, And judging the fault type according to the phase-to-phase voltage amplitude relation and the zero-sequence fault voltage component. Because the photovoltaic power station has small influence on the voltage when being connected into the power grid, the fault type of the alternating current line connected with the photovoltaic power station can be accurately identified through the voltage condition of the side protection installation part of the photovoltaic power station, and the safe and stable operation of the power grid can be ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a flowchart of a phase selection method for a photovoltaic power station to access a power grid according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a photovoltaic power station access power grid provided in an embodiment of the present invention;
FIG. 3 shows a decision k according to an embodiment of the present inventionλA flow chart for judging the relation with a preset threshold value and the fault type;
fig. 4 is a gamma-section diagram of a voltage-sequence fault component phase selection element provided by an embodiment of the present invention;
fig. 5 is a β partition diagram of a voltage sequence fault component phase selection element provided by an embodiment of the present invention;
fig. 6 is an amplitude relationship diagram when an a-phase ground fault with a fault resistance of 1 Ω occurs at a power transmission line f of a photovoltaic power station provided by the embodiment of the present invention;
fig. 7 is a phase relationship diagram of each sequence fault component when an a-phase ground fault with a fault resistance of 100 Ω occurs at a power transmission line f of a photovoltaic power station according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a phase selection device for a photovoltaic power station to access a power grid according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of a phase selection device of a photovoltaic power station connected to a power grid according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 and fig. 2, in which fig. 1 shows a flowchart of a phase selection method for a photovoltaic power plant to access a power grid provided by an embodiment of the present invention, and fig. 2 shows a schematic structural diagram of the photovoltaic power plant to access the power grid provided by the embodiment of the present invention. The phase selection method for the photovoltaic power station to access the power grid provided by the embodiment of the invention can comprise the following steps:
s11: and respectively acquiring three-phase voltages before and during the fault and phase-to-phase voltages before and during the fault of the protection installation at the side of the photovoltaic power station.
Considering that the voltage in the power grid is greatly influenced by the power grid side and hardly influenced by the accessed photovoltaic power station, when the alternating current line fails, in order to enable the phase selection element to accurately identify the fault type of the alternating current line, so that distance protection and automatic reclosing can be correctly operated, and the safe and stable operation of the power grid is ensured, the fault type can be identified through the voltage condition. In addition, it is considered that a line fault occurring on the transmission line of the photovoltaic power plant (e.g., a line fault occurring at the midpoint f of the transmission line of the photovoltaic power plant) has an influence on the protection installation (specifically, M in fig. 2) located on the photovoltaic power plant side, and hardly has an influence on the protection installation located on the synchronous power plant side (E in fig. 2)SRepresenting a synchronous generator), and therefore, only M can be phase-selected using the scheme of the present application, and N can be phase-selected using the existing scheme.
It should be noted that, in a power grid connected with a photovoltaic power station, a detection device having a detection function may detect voltage information of a protection installation (M) on the side of the photovoltaic power station and a protection installation (N) on the side of a synchronous power grid in real time, where the voltage information includes, but is not limited to, three-phase voltages and inter-phase voltages, where the three-phase voltages specifically refer to an a-phase voltage, a B-phase voltage, and a C-phase voltage, and the inter-phase voltages specifically refer to an AB-phase voltage, a BC-phase voltage, and a CA-phase voltage. When a line fault occurs, a memory element in a protection installation place (M place) on the photovoltaic power station side records voltage information of M before the fault and when the fault occurs, and a memory element in a protection installation place (N place) on the synchronous power grid side records voltage information of N before the fault and when the fault occurs.
Therefore, when a fault occurs on a power transmission line of the photovoltaic power station, the phase selection element can acquire the three-phase voltage and the interphase voltage of the protection installation place (M place) on the photovoltaic power station side before the fault from the memory element of the protection installation place (M place) on the photovoltaic power station side, namely, the A-phase voltage of the protection installation place (M place) on the photovoltaic power station side before the fault, namely, the M place is acquired
Figure BDA0002040140920000081
B phase voltage
Figure BDA0002040140920000082
C phase voltage
Figure BDA0002040140920000083
AB phase voltage
Figure BDA0002040140920000084
Phase voltage of BC phase
Figure BDA0002040140920000085
Phase voltage of CA phase
Figure BDA0002040140920000086
And obtaining three-phase voltage and interphase voltage of a protection installation position (M position) at the side of the photovoltaic power station during fault from the memory element, namely obtaining A-phase voltage of the M position during fault
Figure BDA0002040140920000087
B phase voltage
Figure BDA0002040140920000091
C phase voltage
Figure BDA0002040140920000092
AB phase voltage
Figure BDA0002040140920000093
Phase voltage of BC phase
Figure BDA0002040140920000094
Phase voltage of CA phase
Figure BDA0002040140920000095
Wherein [1 ]]When representing a fault, [0 ]]Representing before failure.
S12: and obtaining a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage by using the three-phase voltage, and obtaining an interphase voltage break variable by using the interphase voltage.
After the voltage information of the protection installation position on the photovoltaic power station side is acquired, the phase voltage sudden change can be obtained by using the three-phase voltage of the protection installation position (namely M position) during the fault and the three-phase voltage before the fault, the positive sequence fault voltage component, the negative sequence voltage component and the zero sequence voltage component of the A-phase voltage are obtained, and the phase-to-phase voltage sudden change can be obtained by using the phase-to-phase voltage during the fault and the phase-to-phase voltage before the fault, so that the fault type can be accurately and efficiently judged according to the calculated voltage information in the follow-up process.
S13: obtaining a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase A and the rated voltage amplitude of the phase A before the fault, and judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not;
if the positive sequence voltage droop coefficient is greater than or equal to the preset threshold, the step S14 is executed, and if the positive sequence voltage droop coefficient is less than the preset threshold, the step S15 is executed.
Before or after line fault occurs, the positive sequence voltage amplitude U of the phase A before the fault can be obtainedMa1And can obtain the rated voltage amplitude U of the A phasesThen, using kλ＝UMa1/UsObtaining the positive sequence voltage drop coefficient kλ。
Calculating the positive sequence voltage drop coefficient kλThen, the positive sequence voltage can be dropped by the coefficient kλComparing with a preset threshold value, and judging if the positive sequence voltage drop coefficient k isλIf the voltage drop coefficient is greater than or equal to the preset threshold, step S14 is executed, that is, the phase relation phase selection mode of the voltage sequence fault components is entered, if the positive sequence voltage drop coefficient k isλAnd if the current value is less than the preset threshold value, executing the step S15, namely entering a voltage fault component amplitude relation phase selection mode so as to accurately and quickly identify the fault type when the fault occurs, thereby laying a foundation for the correct action of distance protection and self-weight switching-on.
S14: and obtaining a phase relation through the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage, and determining the fault type through the phase relation, the negative sequence fault voltage component and the zero sequence fault voltage component.
The phase relation phase selection mode of the voltage sequence fault components mentioned above is as follows: and then, determining the fault type according to the phase relation and the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage. The determined fault type includes not only the fault type but also the fault of which phase (i.e. including the fault phase) so that the fault can be handled by corresponding actions, thereby ensuring safe and stable operation of the power grid.
S15: and obtaining a phase voltage amplitude relation through the phase voltage abrupt change, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt change, and determining the fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero-sequence fault voltage component.
The phase selection mode of the voltage fault component amplitude relation mentioned above is as follows: obtaining a phase voltage amplitude relation through three phase voltage abrupt changes of an A phase, a B phase and a C phase, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt changes of the AB phase, the BC phase and the CA phase, and then determining a fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and a zero sequence fault voltage component of the A phase voltage.
According to the technical scheme, the three-phase voltage of the photovoltaic power station side before and during the fault is obtained, the phase voltage of the protection installation before and during the fault is obtained, the three-phase voltage and the phase voltage are used for obtaining the phase voltage break variable, the phase voltage break variable and the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage, the calculated positive sequence voltage drop coefficient is compared with the preset threshold value, when the positive sequence voltage drop coefficient is larger than or equal to the preset threshold value, the fault type is judged according to the phase relation of the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage and the negative sequence fault voltage component and the zero sequence fault voltage component, and when the positive sequence voltage drop coefficient is smaller than or equal to the preset value, the fault type is judged according to the phase voltage amplitude relation, And judging the fault type according to the phase-to-phase voltage amplitude relation and the zero-sequence fault voltage component. Because the photovoltaic power station has small influence on the voltage when being connected into the power grid, the fault type of the alternating current line connected with the photovoltaic power station can be accurately identified through the voltage condition of the side protection installation part of the photovoltaic power station, and the safe and stable operation of the power grid can be ensured.
The phase selection method for the photovoltaic power station to access the power grid provided by the embodiment of the invention obtains the phase voltage break variable and the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A phase voltage by using the three-phase voltage, and obtains the phase voltage break variable by using the phase voltage, and the phase selection method can comprise the following steps:
using the A-phase voltage at fault
Figure BDA0002040140920000101
B phase voltage
Figure BDA0002040140920000102
C phase voltage
Figure BDA0002040140920000103
And a-phase voltage before fault
Figure BDA0002040140920000104
B phase voltage
Figure BDA0002040140920000105
C phase voltage
Figure BDA0002040140920000106
According to
Figure BDA0002040140920000107
Respectively calculating the voltage abrupt change of phase A
Figure BDA0002040140920000108
Abrupt change of phase voltage of phase B
Figure BDA0002040140920000109
C phase voltage abrupt change amount
Figure BDA00020401409200001010
Wherein M is a protection installation position at the side of the photovoltaic power station;
according to
Figure BDA0002040140920000111
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure BDA0002040140920000112
A-phase voltage positive sequence component before fault
Figure BDA0002040140920000113
Negative sequence component of A phase voltage in fault
Figure BDA0002040140920000114
Zero sequence component of A phase voltage in fault
Figure BDA0002040140920000115
And according to
Figure BDA0002040140920000116
Obtaining the positive sequence fault voltage component of A phase voltage
Figure BDA0002040140920000117
According to
Figure BDA0002040140920000118
Obtaining the negative sequence fault voltage component of A phase voltage
Figure BDA0002040140920000119
According to
Figure BDA00020401409200001110
Obtaining the zero-sequence fault voltage component of A-phase voltage
Figure BDA00020401409200001111
Wherein α ═ ej120°；
Using faultsTime AB phase voltage
Figure BDA00020401409200001112
Phase voltage of BC phase
Figure BDA00020401409200001113
Phase voltage of CA phase
Figure BDA00020401409200001114
And AB phase voltage before failure
Figure BDA00020401409200001115
Phase voltage of BC phase
Figure BDA00020401409200001116
Phase voltage of CA phase
Figure BDA00020401409200001117
According to
Figure BDA00020401409200001118
Respectively calculating AB phase voltage abrupt change components
Figure BDA00020401409200001119
BC phase voltage abrupt component
Figure BDA00020401409200001120
Abrupt change component of phase voltage of CA phase
Figure BDA00020401409200001121
When the three-phase voltage is used for obtaining the phase voltage break variable and the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage, and the interphase voltage break variable is obtained by using the interphase voltage, the method can be specifically obtained in the following mode:
acquisition of a-phase voltage before M fails
Figure BDA00020401409200001122
B phase voltage
Figure BDA00020401409200001123
C phase voltage
Figure BDA00020401409200001124
And the A-phase voltage when M is in fault
Figure BDA00020401409200001125
B phase voltage
Figure BDA00020401409200001126
C phase voltage
Figure BDA00020401409200001127
Then, then according to
Figure BDA00020401409200001128
Respectively calculating the voltage abrupt change of phase A
Figure BDA00020401409200001129
Abrupt change of phase voltage of phase B
Figure BDA00020401409200001130
C phase voltage abrupt change amount
Figure BDA00020401409200001131
In addition, after the three-phase voltage before and when M is in fault is acquired, the method can be used
Figure BDA00020401409200001132
Calculating the A phase voltage positive sequence component before fault
Figure BDA00020401409200001133
Wherein α ═ ej120°In particular, namely by using
Figure BDA00020401409200001134
Is calculated to obtain
Figure BDA00020401409200001135
It should be noted that the a-phase voltage negative sequence component and the a-phase voltage zero sequence component do not exist before the fault, that is, the a-phase voltage negative sequence component before the fault does not exist
Figure BDA0002040140920000121
Zero sequence voltage component
Figure BDA0002040140920000122
Are all 0, therefore, there is no need to calculate by the above formula
Figure BDA0002040140920000123
And
Figure BDA0002040140920000124
meanwhile, the A phase voltage positive sequence component in fault can be calculated according to the formula
Figure BDA0002040140920000125
Negative sequence component of A phase voltage in fault
Figure BDA0002040140920000126
Zero sequence component of A phase voltage in fault
Figure BDA0002040140920000127
Specifically, the above formula may then be transformed into
Figure BDA0002040140920000128
To respectively calculate the A phase voltage positive sequence component in fault
Figure BDA0002040140920000129
Negative sequence component of A phase voltage in fault
Figure BDA00020401409200001210
Zero-sequence component of A-phase voltage in fault
Figure BDA00020401409200001211
Then, can utilize
Figure BDA00020401409200001212
Calculating to obtain the positive sequence fault voltage component of the A-phase voltage
Figure BDA00020401409200001213
By using
Figure BDA00020401409200001214
Calculating to obtain the negative sequence fault voltage component of the A phase voltage
Figure BDA00020401409200001215
By using
Figure BDA00020401409200001216
Calculating to obtain the zero-sequence fault voltage component of the A-phase voltage
Figure BDA00020401409200001217
Obtaining AB phase voltage before M is in fault
Figure BDA00020401409200001218
Phase voltage of BC phase
Figure BDA00020401409200001219
Phase voltage of CA phase
Figure BDA00020401409200001220
And AB phase voltage when M is in fault
Figure BDA00020401409200001221
Phase voltage of BC phase
Figure BDA00020401409200001222
Phase voltage of CA phase
Figure BDA00020401409200001223
Thereafter, it is possible to utilize
Figure BDA00020401409200001224
Respectively calculating AB phase voltage abrupt change components
Figure BDA00020401409200001225
BC phase voltage abrupt component
Figure BDA00020401409200001226
Abrupt change component of phase voltage of CA phase
Figure BDA00020401409200001227
So far, the voltage abrupt change of the phase A can be obtained
Figure BDA00020401409200001228
Abrupt change of phase voltage of phase B
Figure BDA00020401409200001229
C phase voltage abrupt change amount
Figure BDA00020401409200001230
Positive sequence fault voltage component of A-phase voltage
Figure BDA00020401409200001231
Negative sequence fault voltage component of A-phase voltage
Figure BDA00020401409200001232
Zero sequence fault voltage component of A-phase voltage
Figure BDA00020401409200001233
AB phase voltage abrupt change component
Figure BDA00020401409200001234
BC phase voltage abrupt component
Figure BDA00020401409200001235
Abrupt change component of phase voltage of CA phase
Figure BDA00020401409200001236
To facilitate inThese voltage information can subsequently be used to make a fault type determination.
Referring to fig. 3 to 5, wherein fig. 3 illustrates a decision k provided by an embodiment of the present inventionλA relationship with a preset threshold value and a flowchart for determining a fault type, fig. 4 shows a γ -partition diagram of a voltage-series fault component phase selection element provided by an embodiment of the present invention, and fig. 5 shows a β -partition diagram of a voltage-series fault component phase selection element provided by an embodiment of the present invention. The phase selection method for the photovoltaic power station to access the power grid provided by the embodiment of the invention obtains the phase relationship through the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage, and determines the fault type through the phase relationship, the negative sequence fault voltage component and the zero sequence fault voltage component, and the method can comprise the following steps:
by using
Figure BDA0002040140920000131
Respectively calculating gamma and beta, wherein arg () represents the argument of the phasor;
judgment of
Figure BDA0002040140920000132
Whether it is equal to 0, where it represents the magnitude of the voltage phasor;
if it is
Figure BDA0002040140920000133
Equal to 0, then judge
Figure BDA0002040140920000134
Whether or not it is equal to 0, if
Figure BDA0002040140920000135
Equal to 0, the three-phase short-circuit fault is judged, if so, the three-phase short-circuit fault is detected
Figure BDA0002040140920000136
If not, judging the interval of beta: if the beta is more than or equal to-120 degrees and less than 0 degree, determining that the AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if beta is more than or equal to 0 degrees and less than 120 degrees, the phase-to-phase short circuit of CA is judged；
If it is
Figure BDA0002040140920000137
Not equal to 0, the fault type is determined by γ and β: if gamma belongs to (-30 degrees, 30 degrees) and belongs to 0(-60 degrees, 60 degrees), determining that the phase A is grounded; if gamma is belonged to 1(90 degrees, 150 degrees) and is belonged to 2(-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma belongs to (-30 degrees, 90 degrees) and beta belongs to (120 degrees, 240 degrees), judging that the BC phase grounding fault exists; if γ ∈ (90 °, 210 °) and β ∈ (0 °, 120 °), it is determined that CA has a ground fault.
The specific process of determining the fault type through the phase relationship and the negative-sequence fault voltage component and the zero-sequence fault voltage component of the a-phase voltage may be as follows:
and gamma and beta are respectively calculated by using the obtained voltage information, wherein,
Figure BDA0002040140920000138
Figure BDA0002040140920000139
arg () represents the argument of the phasor.
Judgment of
Figure BDA00020401409200001310
Whether it is equal to 0, where the amplitude of the voltage phasor is represented: if it is
Figure BDA00020401409200001311
Then judge
Figure BDA00020401409200001312
Whether or not it is equal to 0, if
Figure BDA00020401409200001313
Determining three-phase short circuit fault if
Figure BDA00020401409200001314
Judging the fault type according to beta, specifically, if beta is more than or equal to-120 degrees and less than 0 degree, judging that AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if the beta is more than or equal to 0 degrees and less than 120 degrees, the CA interphase short circuit is judged; if it is
Figure BDA00020401409200001315
Judging the fault type according to gamma and beta at the same time, and specifically judging that the phase A is grounded if gamma belongs to (-30 degrees and 30 degrees) and gamma belongs to 0(-60 degrees and 60 degrees); if gamma is belonged to 1(90 degrees, 150 degrees) and is belonged to 2(-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma belongs to (-30 degrees, 90 degrees) and beta belongs to (120 degrees, 240 degrees), judging that the BC phase grounding fault exists; if γ ∈ (90 °, 210 °) and β ∈ (0 °, 120 °), it is determined that CA has a ground fault.
I.e. at the positive sequence voltage sag factor kλWhen the fault type is larger than or equal to the preset threshold value, the fault type can be accurately and quickly judged through the method, so that a foundation can be laid for correct actions of distance protection and self-weight switching-on.
See fig. 3-5. The phase selection method for the photovoltaic power station to access the power grid provided by the embodiment of the invention obtains a phase voltage amplitude relation through a phase voltage abrupt change, obtains an interphase voltage amplitude relation through an interphase voltage abrupt change, and determines a fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and a zero-sequence fault voltage component, and the method can comprise the following steps:
by using
Figure BDA0002040140920000141
Respectively calculate m1、m2、m3、n1、n2、n3；
Judgment of
Figure BDA0002040140920000142
Whether or not it is equal to 0, wherein it means takingThe magnitude of the voltage phasor;
if it is
Figure BDA0002040140920000143
If n is equal to 0, then n is judged2And n3Whether or not (n) is satisfied2>z)&(1/n3>z), if yes, determining the AB interphase short circuit fault; judging n3And n1Whether or not (n) is satisfied3>z)&(1/n1>z), if yes, determining BC interphase short circuit; judging n1And n2Whether or not (n) is satisfied1>z)&(1/n2>z), if yes, determining that the CA interphase short circuit exists; if n is1、n2、n3Are all (n)2>z)&(1/n3>z)、(n3>z)&(1/n1>z)、(n1>z)&(1/n2>z), judging the three-phase short circuit fault, wherein z is 4-8;
if it is
Figure BDA0002040140920000144
If not equal to 0, m is judged1And m2Whether or not (m) is satisfied1>z)&(1/m2>z), if yes, determining that the phase A is grounded; judgment m2And m3Whether or not (m) is satisfied2>z)&(1/m3>z), if yes, judging that the B phase grounding fault exists; judgment m1And m3Whether or not (m) is satisfied3>z)&(1/m1>z), if yes, judging that the C-phase grounding fault exists;
if m1、m2、m3Are all unsatisfied (m)1>z)&(1/m2>z)、(m2>z)&(1/m3>z)、(m3>z)&(1/m1>z), then two-phase earth fault is judged, wherein two phases in the two-phase earth fault are
Figure BDA0002040140920000145
Two phases with larger amplitude.
The specific process of obtaining the phase voltage amplitude relationship and the phase-to-phase voltage amplitude relationship and determining the fault type through the phase voltage amplitude relationship, the phase-to-phase voltage amplitude relationship and the zero-sequence fault voltage component may be as follows:
calculating m using the obtained voltage information1、m2、m3、n1、n2、n3Wherein, in the step (A),
Figure BDA0002040140920000146
Figure BDA0002040140920000147
judgment of
Figure BDA0002040140920000148
Whether or not it is equal to 0, if
Figure BDA0002040140920000149
Then judge n1、n2、n3Whether an expression for n is satisfied, if n1、n2、n3If the expression about n is satisfied, judging the interphase fault phase according to the expression about n, and if n is satisfied1、n2、n3If the expressions on n are not satisfied, the three-phase short-circuit fault is determined. Specifically, n is judged2And n3Whether or not (n) is satisfied2>z)&(1/n3>z), if yes, determining the AB interphase short circuit fault; judging n3And n1Whether or not (n) is satisfied3>z)&(1/n1>z), if yes, determining BC interphase short circuit; judging n1And n2Whether or not (n) is satisfied1>z)&(1/n2>z), if yes, determining that the CA interphase short circuit exists; if n is1、n2、n3Are all (n)2>z)&(1/n3>z)、(n3>z)&(1/n1>z)、(n1>z)&(1/n2>And z), judging the three-phase short circuit fault, wherein the z is 4-8.
If it is
Figure BDA0002040140920000151
Then m is judged1、m2、m3Whether or not an expression for m is satisfied, if m1、m2、m3And if the expression about m is satisfied, judging the single-phase earth fault according to the expression about m. Specifically, m is judged1And m2Whether or not (m) is satisfied1>z)&(1/m2>z), if yes, determining that the phase A is grounded; judgment m2And m3Whether or not (m) is satisfied2>z)&(1/m3>z), if yes, judging that the B phase grounding fault exists; judgment m1And m3Whether or not (m) is satisfied3>z)&(1/m1>z), if yes, the C-phase grounding fault is judged.
If m1、m2、m3Does not satisfy the expression for m, i.e. if m1、m2、m3Are all unsatisfied (m)1>z)&(1/m2>z)、(m2>z)&(1/m3>z)、(m3>z)&(1/m1>z), determining two phases with larger amplitudes as two-phase ground faults according to the amplitude of the sudden change of the three-phase voltage. In particular, if
Figure BDA0002040140920000152
Determining that the AB phase is grounded; if it is
Figure BDA0002040140920000153
Judging that the BC phase is grounded; if it is
Figure BDA0002040140920000154
It is determined that the CA phase ground failed.
I.e. at the positive sequence voltage sag factor kλWhen the fault type is smaller than the preset threshold value, the fault type can be accurately and quickly judged through the method, so that a foundation can be laid for correct actions of distance protection and self-weight switching-on.
According to the phase selection method for the photovoltaic power station to be connected into the power grid, which is provided by the embodiment of the invention, the preset threshold value is any value in [0.8,0.9 ].
Under the condition of dropping the positive sequence voltage by a coefficient kλWhen comparing with the preset threshold, the preset threshold may be [0.8,0.9]]To improve the accuracy of identifying the fault type.
Of course, the magnitude of the preset threshold value can also be adjusted according to the voltage drop condition, so as to improve the accuracy of identifying the fault type.
In order to more clearly explain the scheme and verify the correctness of the scheme, the phase selection method of the photovoltaic power station accessing to the power grid is simulated. Specifically, simulation is realized in electromagnetic transient simulation software PSCAD/EMTDC by using a Fortran language, wherein simulation model parameters are as follows: the capacity of the photovoltaic power station is 150MW, the photovoltaic power station comprises 7 35kV collecting lines in total, the rated capacity of a main transformer is 200MVA, the rated transformation ratio is 230/37kV, YNd11 wiring groups comprise 16% of short-circuit impedance; the voltage level of a transmission line of the photovoltaic power station is 220kV, the total length of the line is 35km, wherein the positive sequence impedance and the zero sequence impedance of the unit length are respectively (0.0165+ j0.386) omega/km and (0.04+ j0.65) omega/km.
In order to verify the correctness of the phase selection method, it is assumed that a simulation model generates an a-phase ground fault at a midpoint f of a power transmission line of a photovoltaic power station at the time when t is 1s, the fault duration is 0.3s, fault resistances are respectively set to 1 Ω and 100 Ω, and the obtained simulation results are shown in fig. 6 and 7, wherein fig. 6 is an amplitude relation diagram when the a-phase ground fault with the fault resistance of 1 Ω occurs at the power transmission line f of the photovoltaic power station, a diagram positioned at the upper side in fig. 6 is a positive sequence voltage amplitude diagram obtained by sampling at M, at this time, a positive sequence voltage sag coefficient is calculated to be smaller than a preset threshold value, so that a phase selection mode of a voltage fault component amplitude relation is selected, and a diagram positioned at the lower side in fig. 6 is a phase voltage fault component amplitude relation diagram (phase voltage fault component
Figure BDA0002040140920000161
Curve of (1) and
Figure BDA0002040140920000162
almost coincide) of the two, bring it into
Figure BDA0002040140920000163
The phase selection method can accurately judge the type of the fault to be the A-phase grounding fault, wherein the method is shown in FIG. 6
Figure BDA0002040140920000164
That is to say as mentioned above
Figure BDA0002040140920000165
That is to say as mentioned above
Figure BDA0002040140920000166
That is to say as mentioned above
Figure BDA0002040140920000167
Fig. 7 is a phase relation diagram of each sequence fault component when an a-phase ground fault with a fault resistance of 100 Ω occurs at a power transmission line f of a photovoltaic power station, the diagram positioned above in fig. 7 is a positive sequence voltage amplitude diagram obtained by sampling at M, at this time, a positive sequence voltage sag coefficient is greater than a preset threshold value, so that a phase relation phase selection mode of each sequence fault component of voltage is selected to enter, the diagram positioned below in fig. 7 is a sequence voltage amplitude diagram (a negative sequence curve is almost coincident with a zero sequence curve), angles of γ and β are calculated, and it can be known through analysis of phase distribution conditions of γ and β in fig. 4 and 5 that the phase selection method can accurately judge that the type of the occurring fault is the a-phase ground fault.
According to the method, no matter what depth of faults occur to the photovoltaic power station transmission line, the fault type can be accurately identified by the phase selection method, and therefore reliability and sensitivity of protection are effectively improved.
An embodiment of the present invention further provides a phase selection apparatus for a photovoltaic power station to access a power grid, and referring to fig. 8, a schematic structural diagram of the phase selection apparatus for a photovoltaic power station to access a power grid provided in the embodiment of the present invention is shown, and the phase selection apparatus may include:
the acquisition module 11 is used for respectively acquiring three-phase voltages before and during a fault and phase-to-phase voltages before and during the fault of the protection installation at the photovoltaic power station side;
the calculation module 12 is configured to obtain a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the a-phase voltage by using the three-phase voltage, and obtain an interphase voltage break variable by using the interphase voltage;
the judging module 13 is configured to obtain a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase a before the fault and the rated voltage amplitude of the phase a, and judge whether the positive sequence voltage drop coefficient is greater than or equal to a preset threshold;
the first determining module 14 is configured to, when the determining module determines that the positive sequence fault voltage component, the negative sequence fault voltage component, and the zero sequence fault voltage component of the a-phase voltage are the positive sequence fault voltage component, the negative sequence fault voltage component, and the zero sequence fault voltage component, obtain a phase relationship, and determine a fault type according to the phase relationship, the negative sequence fault voltage component, and the zero sequence fault voltage component;
and the second determining module 15 is configured to, when the determining module determines that the fault type is not the fault type, obtain a phase voltage amplitude relationship through the phase voltage abrupt change, obtain an inter-phase voltage amplitude relationship through the inter-phase voltage abrupt change, and determine the fault type according to the phase voltage amplitude relationship, the inter-phase voltage amplitude relationship, and the zero-sequence fault voltage component.
In the phase selection device for the photovoltaic power station to access to the power grid provided by the embodiment of the present invention, the calculation module 12 may include:
a first calculating unit for using the A phase voltage at fault
Figure BDA0002040140920000171
B phase voltage
Figure BDA0002040140920000172
C phase voltage
Figure BDA0002040140920000173
And a-phase voltage before fault
Figure BDA0002040140920000174
B phase voltage
Figure BDA0002040140920000175
C phase voltage
Figure BDA0002040140920000176
According to
Figure BDA0002040140920000177
Respectively calculating the voltage abrupt change of phase A
Figure BDA0002040140920000178
Abrupt change of phase voltage of phase B
Figure BDA0002040140920000179
C phase voltage abrupt change amount
Figure BDA00020401409200001710
Wherein M is a protection installation position at the side of the photovoltaic power station;
a second calculation unit for calculating based on
Figure BDA00020401409200001711
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure BDA00020401409200001712
A-phase voltage positive sequence component before fault
Figure BDA00020401409200001713
Negative sequence component of A phase voltage in fault
Figure BDA00020401409200001714
Zero sequence component of A phase voltage in fault
Figure BDA00020401409200001715
And according to
Figure BDA00020401409200001716
Obtaining the positive sequence fault voltage component of A phase voltage
Figure BDA00020401409200001717
According to
Figure BDA00020401409200001718
Obtaining the negative sequence fault voltage component of A phase voltage
Figure BDA00020401409200001719
According to
Figure BDA00020401409200001720
Obtaining the zero-sequence fault voltage component of A-phase voltage
Figure BDA00020401409200001721
Wherein α ═ ej120°；
A third calculating unit for using the AB phase voltage at the time of failure
Figure BDA00020401409200001722
Phase voltage of BC phase
Figure BDA00020401409200001723
Phase voltage of CA phase
Figure BDA00020401409200001724
And AB phase voltage before failure
Figure BDA00020401409200001725
Phase voltage of BC phase
Figure BDA00020401409200001726
Phase voltage of CA phase
Figure BDA00020401409200001727
According to
Figure BDA00020401409200001728
Respectively calculating AB phase voltage abrupt change components
Figure BDA00020401409200001729
BC phase voltage abrupt component
Figure BDA00020401409200001730
Abrupt change component of phase voltage of CA phase
Figure BDA00020401409200001731
In the phase selection device for the photovoltaic power station to access to the power grid provided by the embodiment of the present invention, the first determining module 14 may include:
a fourth calculation unit for utilizing
Figure BDA00020401409200001732
Respectively calculating gamma and beta, wherein arg () represents the argument of the phasor;
a first judgment unit for judging
Figure BDA00020401409200001733
Whether it is equal to 0, where it represents the magnitude of the voltage phasor;
a first determination unit for determining if
Figure BDA0002040140920000181
Equal to 0, then judge
Figure BDA0002040140920000182
Whether or not it is equal to 0, if
Figure BDA0002040140920000183
Equal to 0, the three-phase short-circuit fault is judged, if so, the three-phase short-circuit fault is detected
Figure BDA0002040140920000184
If not, judging the interval of beta: if the beta is more than or equal to-120 degrees and less than 0 degree, determining that the AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if the beta is more than or equal to 0 degrees and less than 120 degrees, the CA interphase short circuit is judged;
a second determination unit for determining if
Figure BDA0002040140920000185
Not equal to 0, the fault type is determined by γ and β: if gamma belongs to (-30 degrees, 30 degrees) and beta belongs to arg (-60 degrees, 60 degrees), determining that the phase A is grounded; if γ belongs to (-30 °, 30 °) and β belongs to (-60 °, 60 °), the phase A is determinedA ground fault; if gamma belongs to (90 degrees, 150 degrees) and beta belongs to (-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma belongs to (-30 degrees, 90 degrees) and beta belongs to (120 degrees, 240 degrees), judging that the BC phase grounding fault exists; if γ ∈ (90 °, 210 °) and β ∈ (0 °, 120 °), it is determined that CA has a ground fault.
In addition, according to the phase selection device of the photovoltaic power station accessed to the power grid provided by the embodiment of the present invention, the second determining module 15 may include:
a fifth calculation unit for utilizing
Figure BDA0002040140920000186
Figure BDA0002040140920000187
Respectively calculate m1、m2、m3、n1、n2、n3；
A second judgment unit for judging
Figure BDA0002040140920000188
Whether it is equal to 0, where it represents the magnitude of the voltage phasor;
a third determination unit for determining if
Figure BDA0002040140920000189
If n is equal to 0, then n is judged2And n3Whether or not (n) is satisfied2>z)&(1/n3>z), if yes, determining the AB interphase short circuit fault; judging n3And n1Whether or not (n) is satisfied3>z)&(1/n1>z), if yes, determining BC interphase short circuit; judging n1And n2Whether or not (n) is satisfied1>z)&(1/n2>z), if yes, determining that the CA interphase short circuit exists; if n is1、n2、n3Are all (n)2>z)&(1/n3>z)、(n3>z)&(1/n1>z)、(n1>z)&(1/n2>z), judging the three-phase short circuit fault, wherein z is 4-8;
a fourth determination unit for determining if
Figure BDA00020401409200001810
If not equal to 0, m is judged1And m2Whether or not (m) is satisfied1>z)&(1/m2>z), if yes, determining that the phase A is grounded; judgment m2And m3Whether or not (m) is satisfied2>z)&(1/m3>z), if yes, judging that the B phase grounding fault exists; judgment m1And m3Whether or not (m) is satisfied3>z)&(1/m1>z), if yes, judging that the C-phase grounding fault exists;
a fifth judging unit for judging if m1、m2、m3Are all unsatisfied (m)1>z)&(1/m2>z)、(m2>z)&(1/m3>z)、(m3>z)&(1/m1>z), then two-phase earth fault is judged, wherein two phases in the two-phase earth fault are
Figure BDA00020401409200001811
Two phases with larger amplitude.
An embodiment of the present invention further provides a phase selection device for a photovoltaic power station to access a power grid, where reference is made to fig. 9, which shows a schematic structural diagram of the phase selection device for the photovoltaic power station to access the power grid according to the embodiment of the present invention, and the phase selection device may include:
a memory 21 for storing a computer program;
and the processor 22 is used for implementing the steps of the phase selection method for accessing the photovoltaic power station to the power grid when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and when being executed by a processor, the computer program realizes the steps of any phase selection method for the photovoltaic power station to be accessed to the power grid.
For a description of relevant parts in the phase selection device, the equipment and the computer-readable storage medium for the photovoltaic power station to access the power grid provided by the embodiment of the present invention, reference is made to detailed descriptions of corresponding parts in the installation method for the photovoltaic power station to access the power grid provided by the embodiment of the present invention, and details are not repeated herein.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include elements inherent in the list. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. In addition, parts of the above technical solutions provided in the embodiments of the present invention that are consistent with the implementation principles of the corresponding technical solutions in the prior art are not described in detail, so as to avoid redundant description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A phase selection method for a photovoltaic power station to be connected into a power grid is characterized by comprising the following steps:
respectively acquiring three-phase voltages before and during fault and interphase voltages before and during fault of protection installation at the side of the photovoltaic power station;
the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the phase voltage break variable and the phase voltage A are obtained by utilizing the three-phase voltage, and the interphase voltage break variable is obtained by utilizing the interphase voltage, and the method comprises the following steps:
using the A-phase voltage at fault
Figure FDA0002976161700000011
B phase voltage
Figure FDA0002976161700000012
C phase voltage
Figure FDA0002976161700000013
And a-phase voltage before fault
Figure FDA0002976161700000014
B phase voltage
Figure FDA0002976161700000015
C phase voltage
Figure FDA0002976161700000016
According to
Figure FDA0002976161700000017
Respectively calculating the voltage abrupt change of phase A
Figure FDA0002976161700000018
Abrupt change of phase voltage of phase B
Figure FDA0002976161700000019
C phase voltage abrupt change amount
Figure FDA00029761617000000110
Wherein M is a protection installation position at the side of the photovoltaic power station;
according to
Figure FDA00029761617000000111
Respectively calculate the resultsPhase-locked A-phase voltage positive sequence component
Figure FDA00029761617000000112
A-phase voltage positive sequence component before fault
Figure FDA00029761617000000113
Negative sequence component of A phase voltage in fault
Figure FDA00029761617000000114
Zero sequence component of A phase voltage in fault
Figure FDA00029761617000000115
Specifically, the method comprises the following steps: according to
Figure FDA00029761617000000116
Calculating to obtain the positive sequence component of the A phase voltage before the fault
Figure FDA00029761617000000117
According to
Figure FDA00029761617000000118
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure FDA00029761617000000119
Negative sequence component of A phase voltage in fault
Figure FDA00029761617000000120
Zero-sequence component of A-phase voltage in fault
Figure FDA00029761617000000121
And according to
Figure FDA00029761617000000122
Obtaining the positive sequence fault voltage component of A phase voltage
Figure FDA00029761617000000123
According to
Figure FDA00029761617000000124
Obtaining the negative sequence fault voltage component of A phase voltage
Figure FDA00029761617000000125
According to
Figure FDA00029761617000000126
Obtaining the zero-sequence fault voltage component of A-phase voltage
Figure FDA00029761617000000127
Wherein α ═ ej120°；
Using AB-phase voltage at fault
Figure FDA00029761617000000128
Phase voltage of BC phase
Figure FDA00029761617000000129
Phase voltage of CA phase
Figure FDA00029761617000000130
And AB phase voltage before failure
Figure FDA00029761617000000131
Phase voltage of BC phase
Figure FDA00029761617000000132
Phase voltage of CA phase
Figure FDA00029761617000000133
According to
Figure FDA0002976161700000021
Respectively calculating AB phase voltage abrupt change components
Figure FDA0002976161700000022
BC phase voltage abrupt component
Figure FDA0002976161700000023
Abrupt change component of phase voltage of CA phase
Figure FDA0002976161700000024
Obtaining a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase A and the rated voltage amplitude of the phase A before the fault, and judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not;
if yes, obtaining a phase relation through a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage, and determining a fault type through the phase relation, the negative sequence fault voltage component and the zero sequence fault voltage component, wherein the fault type comprises the following steps:
by using
Figure FDA0002976161700000025
Respectively calculating gamma and beta, wherein arg () represents the argument of the phasor;
judgment of
Figure FDA0002976161700000026
Whether it is equal to 0, where | represents the magnitude of the voltage phasor;
if it is
Figure FDA0002976161700000027
Equal to 0, then judge
Figure FDA0002976161700000028
Whether or not it is equal to 0, if
Figure FDA0002976161700000029
Equal to 0, the three-phase short-circuit fault is judged, if so, the three-phase short-circuit fault is detected
Figure FDA00029761617000000210
If not, judging the interval of beta: if the beta is more than or equal to-120 degrees and less than 0 degree, determining that the AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if the beta is more than or equal to 0 degrees and less than 120 degrees, the CA interphase short circuit is judged;
if it is
Figure FDA00029761617000000211
Not equal to 0, the fault type is determined by γ and β: if gamma belongs to (-30 degrees, 30 degrees) and belongs to 0(-60 degrees, 60 degrees), determining that the phase A is grounded; if gamma is belonged to 1(90 degrees, 150 degrees) and is belonged to 2(-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma belongs to (-30 degrees, 90 degrees) and beta belongs to (120 degrees, 240 degrees), judging that the BC phase grounding fault exists; if gamma belongs to (90 degrees, 210 degrees) and beta belongs to (0 degrees, 120 degrees), judging that the CA is in grounding fault;
if not, obtaining a phase voltage amplitude relation through the phase voltage abrupt change, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt change, and determining a fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero-sequence fault voltage component.
2. The phase selection method for the photovoltaic power station to access the power grid according to claim 1, wherein the step of obtaining a phase voltage amplitude relationship through the phase voltage abrupt change, obtaining an inter-phase voltage amplitude relationship through the inter-phase voltage abrupt change, and determining the fault type through the phase voltage amplitude relationship, the inter-phase voltage amplitude relationship and the zero-sequence fault voltage component comprises the steps of:
by using
Figure FDA0002976161700000031
Respectively calculate m1、m2、m3、n1、n2、n3；
Judgment of
Figure FDA0002976161700000032
Whether it is equal to 0, where | represents the magnitude of the voltage phasor;
if it is
Figure FDA0002976161700000033
If n is equal to 0, then n is judged2And n3Whether or not (n) is satisfied2>z)&(1/n3>z), if yes, determining the AB interphase short circuit fault; judging n3And n1Whether or not (n) is satisfied3>z)&(1/n1>z), if yes, determining BC interphase short circuit; judging n1And n2Whether or not (n) is satisfied1>z)&(1/n2>z), if yes, determining that the CA interphase short circuit exists; if n is1、n2、n3Are all (n)2>z)&(1/n3>z)、(n3>z)&(1/n1>z)、(n1>z)&(1/n2>z), judging the three-phase short circuit fault, wherein z is 4-8;
if it is
Figure FDA0002976161700000034
If not equal to 0, m is judged1And m2Whether or not (m) is satisfied1>z)&(1/m2>z), if yes, determining that the phase A is grounded; judgment m2And m3Whether or not (m) is satisfied2>z)&(1/m3>z), if yes, judging that the B phase grounding fault exists; judgment m1And m3Whether or not (m) is satisfied3>z)&(1/m1>z), if yes, judging that the C-phase grounding fault exists;
if m1、m2、m3Are all unsatisfied (m)1>z)&(1/m2>z)、(m2>z)&(1/m3>z)、(m3>z)&(1/m1>z), judging two-phase ground fault, wherein two phases in the two-phase ground fault are
Figure FDA0002976161700000035
Two phases with larger amplitude.
3. The phase selection method for the photovoltaic power plant access grid according to any of the claims 1 to 2, characterized in that said preset threshold value is any value of [0.8,0.9 ].
4. A phase selection device for a photovoltaic power station to be connected into a power grid is characterized by comprising:
the acquisition module is used for respectively acquiring three-phase voltages of the protection installation position on the side of the photovoltaic power station before and during the fault and interphase voltages before and during the fault;
the calculation module is used for obtaining a phase voltage break variable and a positive sequence fault voltage component, a negative sequence fault voltage component and a zero sequence fault voltage component of the A-phase voltage by using the three-phase voltage, and obtaining an interphase voltage break variable by using the interphase voltage;
the calculation module comprises:
a first calculating unit for using the A phase voltage at fault
Figure FDA0002976161700000036
B phase voltage
Figure FDA0002976161700000037
C phase voltage
Figure FDA0002976161700000038
And a-phase voltage before fault
Figure FDA0002976161700000039
B phase voltage
Figure FDA00029761617000000310
C phase voltage
Figure FDA00029761617000000311
According to
Figure FDA00029761617000000312
Respectively calculating the voltage abrupt change of phase A
Figure FDA00029761617000000313
Abrupt change of phase voltage of phase B
Figure FDA00029761617000000314
C phase voltage abrupt change amount
Figure FDA00029761617000000315
Wherein M is a protection installation position at the side of the photovoltaic power station;
a second calculation unit for calculating based on
Figure FDA0002976161700000041
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure FDA0002976161700000042
A-phase voltage positive sequence component before fault
Figure FDA0002976161700000043
Negative sequence component of A phase voltage in fault
Figure FDA0002976161700000044
Zero sequence component of A phase voltage in fault
Figure FDA0002976161700000045
Specifically, the method comprises the following steps: according to
Figure FDA0002976161700000046
Calculating to obtain the positive sequence component of the A phase voltage before the fault
Figure FDA0002976161700000047
According to
Figure FDA0002976161700000048
Respectively calculating the positive sequence components of the A-phase voltage in fault
Figure FDA0002976161700000049
Negative sequence component of A phase voltage in fault
Figure FDA00029761617000000410
Zero-sequence component of A-phase voltage in fault
Figure FDA00029761617000000411
And according to
Figure FDA00029761617000000412
Obtaining the positive sequence fault voltage component of A phase voltage
Figure FDA00029761617000000413
According to
Figure FDA00029761617000000414
Obtaining the negative sequence fault voltage component of A phase voltage
Figure FDA00029761617000000415
According to
Figure FDA00029761617000000416
Obtaining the zero-sequence fault voltage component of A-phase voltage
Figure FDA00029761617000000417
Wherein α ═ ej120°；
A third calculating unit for using the AB phase voltage at the time of failure
Figure FDA00029761617000000418
Phase voltage of BC phase
Figure FDA00029761617000000419
Phase voltage of CA phase
Figure FDA00029761617000000420
And AB phase voltage before failure
Figure FDA00029761617000000421
Phase voltage of BC phase
Figure FDA00029761617000000422
Phase voltage of CA phase
Figure FDA00029761617000000423
According to
Figure FDA00029761617000000424
Respectively calculating AB phase voltage abrupt change components
Figure FDA00029761617000000425
BC phase voltage abrupt component
Figure FDA00029761617000000426
Abrupt change component of phase voltage of CA phase
Figure FDA00029761617000000427
The judging module is used for obtaining a positive sequence voltage drop coefficient according to the positive sequence voltage amplitude of the phase A and the rated voltage amplitude of the phase A before the fault, and judging whether the positive sequence voltage drop coefficient is larger than or equal to a preset threshold value or not;
the first determining module is used for obtaining a phase relationship through the positive sequence fault voltage component, the negative sequence fault voltage component and the zero sequence fault voltage component of the A-phase voltage and determining a fault type through the phase relationship, the negative sequence fault voltage component and the zero sequence fault voltage component when the judging module judges that the A-phase voltage is positive;
the first determining module includes:
a fourth calculation unit for utilizing
Figure FDA00029761617000000428
Respectively calculating gamma and beta, wherein arg () represents the argument of the phasor;
a first judgment unit for judging
Figure FDA0002976161700000051
Whether it is equal to 0, where | represents the magnitude of the voltage phasor;
a first determination unit for determining if
Figure FDA0002976161700000052
Equal to 0, then judge
Figure FDA0002976161700000053
Whether or not it is equal to 0, if
Figure FDA0002976161700000054
Equal to 0, the three-phase short-circuit fault is judged, if so, the three-phase short-circuit fault is detected
Figure FDA0002976161700000055
If not, judging the interval of beta: if the beta is more than or equal to-120 degrees and less than 0 degree, determining that the AB interphase short circuit exists; if the beta is more than or equal to 120 degrees and less than 240 degrees, judging the BC interphase short circuit; if the beta is more than or equal to 0 degrees and less than 120 degrees, the CA interphase short circuit is judged;
a second determination unit for determining if
Figure FDA0002976161700000056
Not equal to 0, the fault type is determined by γ and β: if gamma belongs to (-30 degrees, 30 degrees) and beta belongs to (-60 degrees, 60 degrees), determining that the phase A is grounded; if gamma belongs to (90 degrees, 150 degrees) and beta belongs to (-180 degrees, -60 degrees), judging that the phase B is in grounding fault; if gamma belongs to (-150 degrees, -90 degrees) and beta belongs to (60 degrees, 180 degrees), judging that the phase C is grounded; if gamma belongs to (-150 degrees, -30 degrees) and beta belongs to (-120 degrees, 0 degrees), determining that the AB phase is grounded; if gamma is formed as (-30 deg. °)90 DEG and beta belongs to (120 DEG and 240 DEG), judging that the BC phase grounding fault exists; if gamma belongs to (90 degrees, 210 degrees) and beta belongs to (0 degrees, 120 degrees), judging that the CA is in grounding fault;
and the second determining module is used for obtaining a phase voltage amplitude relation through the phase voltage abrupt change if the judging module judges that the fault type is not the zero sequence fault voltage component, obtaining an interphase voltage amplitude relation through the interphase voltage abrupt change, and determining the fault type through the phase voltage amplitude relation, the interphase voltage amplitude relation and the zero sequence fault voltage component.
5. The utility model provides a photovoltaic power plant inserts phase selection equipment of electric wire netting which characterized in that includes:
a memory for storing a computer program;
a processor for implementing the steps of the phase selection method of a photovoltaic power plant into a power grid according to any one of claims 1 to 3 when executing said computer program.
6. A computer-readable storage medium, characterized in that a computer program is stored thereon, which computer program, when being executed by a processor, realizes the steps of the phase selection method of a photovoltaic power plant access grid according to any one of claims 1 to 3.
CN201910339165.4A 2019-04-25 2019-04-25 Phase selection method and device for photovoltaic power station to access power grid Active CN109975662B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910339165.4A CN109975662B (en) 2019-04-25 2019-04-25 Phase selection method and device for photovoltaic power station to access power grid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910339165.4A CN109975662B (en) 2019-04-25 2019-04-25 Phase selection method and device for photovoltaic power station to access power grid

Publications (2)

Publication Number Publication Date
CN109975662A CN109975662A (en) 2019-07-05
CN109975662B true CN109975662B (en) 2021-05-11

Family

ID=67086343

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910339165.4A Active CN109975662B (en) 2019-04-25 2019-04-25 Phase selection method and device for photovoltaic power station to access power grid

Country Status (1)

Country Link
CN (1) CN109975662B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110703134B (en) * 2019-10-15 2022-02-15 南京国电南自电网自动化有限公司 Small current grounding line selection and phase selection method based on fault sequence component
CN112014684B (en) * 2020-08-12 2023-04-18 艾伏新能源科技(上海)股份有限公司 High-precision detection method for three-phase voltage unbalance drop fault and phase jump fault
CN112698236B (en) * 2020-12-28 2023-04-11 深圳供电局有限公司 Station power failure judgment method and device, computer equipment and storage medium
CN112505586A (en) * 2020-12-28 2021-03-16 国网河北省电力有限公司电力科学研究院 Fault detection method and device for distribution line in photovoltaic grid-connected power generation system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101325330A (en) * 2008-07-30 2008-12-17 北京四方继保自动化股份有限公司 Method for implementing earthing distance measurement element
CN102818973A (en) * 2012-09-03 2012-12-12 武汉大学 Phase sequence voltage amplitude comparison-based failure phase selection method and device
JP2016171662A (en) * 2015-03-12 2016-09-23 オムロン株式会社 Isolated operation detector, power conversion system, and isolated operation detection method
CN109581148A (en) * 2018-11-13 2019-04-05 广东电网有限责任公司 A kind of fault phase-selecting method of new energy electric field interconnection

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101325330A (en) * 2008-07-30 2008-12-17 北京四方继保自动化股份有限公司 Method for implementing earthing distance measurement element
CN102818973A (en) * 2012-09-03 2012-12-12 武汉大学 Phase sequence voltage amplitude comparison-based failure phase selection method and device
JP2016171662A (en) * 2015-03-12 2016-09-23 オムロン株式会社 Isolated operation detector, power conversion system, and isolated operation detection method
CN109581148A (en) * 2018-11-13 2019-04-05 广东电网有限责任公司 A kind of fault phase-selecting method of new energy electric field interconnection

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
余良."微电网中的故障选相与定位技术研究".《中国优秀硕士学位论文全文数据库·工程科技Ⅱ辑》.2019,(第1期),第C042-2903页. *
王紫薇等."适用于双馈风电场联络线故障选相方法".《电力系统自动化》.2018,第42卷(第8期),第170-176页. *

Also Published As

Publication number Publication date
CN109975662A (en) 2019-07-05

Similar Documents

Publication Publication Date Title
CN109975662B (en) Phase selection method and device for photovoltaic power station to access power grid
JP2021081400A (en) Line selection method of one-phase ground fault of distribution line and storage medium capable of performing computer-reading
Cordova et al. Fault location identification in smart distribution networks with distributed generation
Jia et al. Sparse voltage amplitude measurement based fault location in large-scale photovoltaic power plants
CN111948491B (en) Transient signal-based active power distribution network multi-terminal quantity fault identification method and system
CN107508265B (en) Small resistance grounding system high resistance earthing protecting method and system
Dharmapandit et al. Detection, classification, and location of faults on grid‐connected and islanded AC microgrid
CN101915888A (en) Extensible fusion identification method for lightening interference of +/-800kV direct current transmission line
Abasi et al. Fault classification and fault area detection in GUPFC-compensated double-circuit transmission lines based on the analysis of active and reactive powers measured by PMUs
CN109061376A (en) A kind of judgment method of Small Electric Current Earthing And Routing Device CT incorrect polarity
Das et al. Effects of distributed generators on impedance-based fault location algorithms
CN107315127B (en) High resistance earthing fault wireline inspection method and system
CN109066621B (en) Fault current calculation method, system and equipment for active power distribution network
Li et al. Analysis and calculation method for multiple faults in low-resistance grounded systems with inverter-interfaced distributed generators based on a PQ control strategy
CN104868478A (en) Method for starting dynamic partitioning scheme under condition of power grid emergency
CN112269101B (en) Single-phase disconnection fault positioning method for power distribution network with distributed power supply
CN107179476B (en) Distribution network fault distance measurement method
Mohamed et al. A multi-agent system for fault location and service restoration in power distribution systems
CN108957234A (en) Power distribution network earthing wire-selecting method and system based on volume measuring point and failure longitudinal direction feature
CN113437732B (en) Pilot protection method and system for photovoltaic power generation grid-connected tie line
Ghorbani et al. Distance protection with fault resistance compensation for lines connected to PV plant
Fan Advanced fault area identification and fault location for transmission and distribution systems
CN113625197A (en) Method, device and equipment for verifying protection polarity of 500kV transformer substation in cold test period of nuclear power plant
CN113687188A (en) Fault line selection method and device based on two-stage zero-sequence power change
Guillen Fault location identification in smart distribution networks with distributed generation

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant