CN111313389B - Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply - Google Patents

Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply Download PDF

Info

Publication number
CN111313389B
CN111313389B CN202010222925.6A CN202010222925A CN111313389B CN 111313389 B CN111313389 B CN 111313389B CN 202010222925 A CN202010222925 A CN 202010222925A CN 111313389 B CN111313389 B CN 111313389B
Authority
CN
China
Prior art keywords
fault
pcc
distributed power
bus
current
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
CN202010222925.6A
Other languages
Chinese (zh)
Other versions
CN111313389A (en
Inventor
李海锋
邓成江
许灿雄
王钢
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.)
South China University of Technology SCUT
Original Assignee
South China University of Technology SCUT
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 South China University of Technology SCUT filed Critical South China University of Technology SCUT
Priority to CN202010222925.6A priority Critical patent/CN111313389B/en
Publication of CN111313389A publication Critical patent/CN111313389A/en
Application granted granted Critical
Publication of CN111313389B publication Critical patent/CN111313389B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices

Abstract

The invention belongs to the field of relay protection of power systems, and relates to a self-adaptive pilot protection method for a power distribution network containing an inverter type distributed power supply, which comprises the following steps: initializing line parameters; setting the installed capacity of each distributed power supply; acquiring voltage vector and current vectors before and after a fault; setting action threshold delta I 'of fault component current differential protection'IBDG_threAnd a braking coefficient k'res(ii) a Calculating positive sequence voltage of each PCC before failure; calculating the sum of the output power of the distributed power supply; calculating the reference active power of the distributed power supply; calculating the positive sequence voltage of the fault component of each PCC to obtain the fault component output current of the distributed power supply; calculating fault component differential current delta I 'of line'dAnd braking current delta I'r(ii) a Judging delta I'dWhether or not to be simultaneously greater than k'resΔI'rAnd Δ I'IBDG_threIf yes, judging the fault in the area and starting a protection action; otherwise, no intra-zone failure is indicated. The invention is not influenced by the type of line fault, transition resistance, access capacity of the distributed power supply, access position and the like, and has strong applicability and high reliability.

Description

Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply
Technical Field
The invention belongs to the field of relay protection of power systems, and relates to a self-adaptive pilot protection method for a power distribution network containing an inverter type distributed power supply.
Background
In order to relieve the energy crisis and reduce the environmental pollution, the distributed power generation technology based on renewable energy sources such as solar energy, wind energy and the like is rapidly developed and widely applied. The permeability of distributed power supplies, especially inverter-type distributed power supplies, in the power grid is increasing. However, the access of the inverter type distributed power supply changes the structure of the traditional power distribution network, so that the single-power-supply radiation type network is converted into a multi-source network. Moreover, the output of the inverter type distributed power supply depends on the control strategy, the fault response speed is high, and the transient process can be ignored, which is greatly different from the traditional power supply. In addition, the output of the inverter type distributed power source using renewable energy also has intermittency and volatility. These factors all present significant challenges to the protection of conventional power distribution networks.
Pilot protection has also been introduced into power distribution networks containing distributed power Supplies (IBDGs) because of its good selectivity and snap-action. For a medium-voltage distribution network, a distributed power supply can be accessed into a power grid through a transformer substation, and can also be accessed into the network in a T-access mode. In actual engineering, the T-connection mode has the advantages of flexible access position, low investment cost and the like, and the T-connection mode is mainly adopted for direct grid connection of small and medium-sized distributed power supplies. However, in such a grid-connected mode, the injection current of the distributed power supply is unknown for the protection devices at two ends of the line, which makes it difficult for conventional pilot protection to take into account both the selectivity and the sensitivity. Therefore, in order to solve the problem of power distribution network protection caused by grid-connected operation of a high-permeability T-type distributed power supply, improvement needs to be carried out on the principle and strategy.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a self-adaptive pilot protection method for a power distribution network containing an inverter type distributed power supply, which aims to effectively solve the relay protection problem when a high-permeability distributed power supply is T-connected to a circuit.
A self-adaptive pilot protection method for a power distribution network containing an inverter type distributed power supply comprises the following steps:
s1, powering on the relay protection device;
s2, initializing line parameters;
s3, setting the installed capacity of each distributed power supply;
s4, respectively sampling and converting three-phase voltage and three-phase current before and after the fault of the bus M and the bus N by the relay protection devices at the bus M and the bus N to obtain positive sequence voltage vectors before the fault of the bus M and the fault of the bus N
Figure BDA0002426705710000011
And fault component voltage vectors of bus M and bus N
Figure BDA0002426705710000012
And fault component current vector
Figure BDA0002426705710000013
Simultaneous acquisitionActive power P flowing through bus M and bus NM、PN；
S5, setting operation threshold delta I 'of fault component current differential protection'IBDG_threAnd a braking coefficient k'res；
S6, deducing the positive sequence voltage of each PCC before the fault according to the positive sequence voltage vectors before the fault of the bus M and the bus N
Figure BDA0002426705710000021
S7, calculating the sum P of the output active power of the distributed power supply on the line MNout；
S8, distributing according to the ratio of the installed capacity of each distributed power supply to the total capacity of the distributed power supplies on the line MN to obtain the reference active power of each distributed power supply;
s9, respectively deducing the fault component positive sequence voltage of each PCC by the relay protection devices at the bus M and the bus N
Figure BDA0002426705710000022
Obtaining actual fault component positive sequence voltage of each PCC;
s10, calculating the estimated value of the fault component current of each distributed power supply according to the positive sequence voltage of each PCC before the fault, the reference active power of each distributed power supply and the actual fault component positive sequence voltage of each PCC
Figure BDA0002426705710000023
S11, current vector according to fault component
Figure BDA0002426705710000024
And fault component current estimates for distributed power sources
Figure BDA0002426705710000025
Calculating fault component differential current delta I 'of line'dAnd braking current delta I'r；
S12, judging fault component differential current delta I'dWhether or not to be simultaneously greater than k'resΔI'rAnd Δ I'IBDG_threIf yes, judging the fault in the area and starting a protection action; otherwise, no intra-zone fault is indicated, and the process returns to step S4.
Preferably, the operation threshold Δ I 'of the fault component current differential protection'IBDG_threAnd a braking coefficient k'resThe calculation method is as follows:
Figure BDA0002426705710000026
Figure BDA0002426705710000027
in the formula,. DELTA.Ithre＝KerKstKnpIn，KerFor transmission error of current transformers, KstIs the same type coefficient of mutual inductor, KnpIs a coefficient of a non-periodic component, InRated current flowing through the mutual inductor; kerrFor the distributed power supply fault component current maximum error coefficient,
Figure BDA0002426705710000028
rated current of the distributed power supply in a protection range; delta Iu′nbIs the unbalanced fault component current in the case of an out-of-range fault; delta l'r.min＝ΔI'IBDG_thre/kres，kresIs the braking coefficient of a conventional distribution network.
Preferably, the positive sequence voltage of each PCC before failure
Figure BDA0002426705710000029
The calculation method is as follows:
Figure BDA00024267057100000210
in the formula (I), the compound is shown in the specification,
Figure BDA00024267057100000211
the positive sequence voltage of the jth PCC when the system normally operates;
Figure BDA00024267057100000212
the positive sequence voltage vector is the positive sequence voltage vector before the fault of the bus M and the bus N; zM-NAnd ZM-jRespectively the impedance of the line MN and the impedances of the bus M to the jth PCC.
Preferably, the sum P of the output active power of the distributed power supplies on the line MNoutThe calculation method is as follows:
Figure BDA0002426705710000031
in the formula: poutThe total active power output by the distributed power supply in the line MN when the power grid operates normally is represented; pM、PNRespectively the active power flowing through the bus M and the bus N; rM-NIs the resistance of line MN.
Preferably, the reference active power P of each distributed power supplyIBDGjThe calculation method is as follows:
Figure BDA0002426705710000032
in the formula, SIBDGjIndicating the installed capacity of the jth distributed power source.
Preferably, the first and second electrodes are formed of a metal,
Figure BDA0002426705710000033
the calculation method is as follows:
Figure BDA0002426705710000034
in the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000035
represents the fault component positive sequence voltage of the PCC at node k derived from the bus M side; zM-jIs the impedance between bus M and the jth PCC; zM-dIs the impedance between bus M and the d-th PCC;
Figure BDA0002426705710000036
the calculated value of the distributed power supply fault component output current at the jth PCC deduced from the bus M side in the protection range,
Figure BDA0002426705710000037
the calculation method is as follows:
Figure BDA0002426705710000038
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure BDA0002426705710000039
and
Figure BDA00024267057100000310
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage during the fault deduced from the M side; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting a distributed power supply reference active power; a represents the phase of the distributed power supply output current relative to the voltage before the fault; i represents an imaginary part; rel () represents the calculation of the real part.
Preferably, the first and second electrodes are formed of a metal,
Figure BDA0002426705710000041
the calculation method is as follows:
Figure BDA0002426705710000042
in the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000043
represents the fault component positive sequence voltage of PCC at node k derived from bus N side; zN-jIs the impedance between bus N and the jth PCC; zN-dIs the impedance between bus N and the d-th PCC;
Figure BDA0002426705710000044
the calculated value of the distributed power source fault component output current at the jth PCC derived from the N side of the bus in the protection range,
Figure BDA0002426705710000045
the calculation method is as follows:
Figure BDA0002426705710000046
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure BDA0002426705710000047
and
Figure BDA0002426705710000048
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage during the fault deduced from the N side; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting a distributed power supply reference active power; alpha represents the output current of the distributed power supply relative to the voltage before the faultThe phase of (d); i denotes the imaginary part and rel () denotes the real part of the computation.
Preferably, the calculation method of the actual fault component positive sequence voltage of each PCC is:
Figure BDA0002426705710000051
in the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000052
a fault component positive sequence voltage actual value of a kth PCC;
Figure BDA0002426705710000053
and
Figure BDA0002426705710000054
and respectively calculating the fault component positive sequence voltage of the kth PCC derived from the side of the bus M and the bus N.
Preferably, the fault component current estimate for the distributed power source at the jth PCC
Figure BDA0002426705710000055
The calculation method is as follows:
Figure BDA0002426705710000056
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure BDA0002426705710000057
and
Figure BDA0002426705710000058
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage actual value during the fault; kmaxTo representA maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjThe reference active power of the distributed power supply is represented, alpha represents the phase of the output current of the distributed power supply relative to the voltage before the fault, i represents an imaginary part, and rel () represents a real part of calculation.
Preferably, the fault component differential current Δ I 'of the line'dAnd braking current delta I'rThe calculation method is as follows:
Figure BDA0002426705710000059
compared with the prior art, the invention has at least the following beneficial effects:
1. the invention is not influenced by the line fault type, the transition resistance, the access capacity and the access position of the distributed power supply, and has strong applicability and high reliability.
2. The invention aims at solving the relay protection problem of the inverter type distributed power distribution network with high permeability, can effectively solve the adverse effect of the access of a plurality of inverter type distributed power supplies on the line protection, protects the inverter type distributed power supplies from the influence of the capacity, the access positions and the number of the distributed power supplies, and has strong applicability.
3. The method fully utilizes the electrical information on two sides of the line to deduce the positive sequence voltage before the fault of each PCC (Point of Common Coupling) and the positive sequence voltage of the fault component during the fault, and further estimates the fault component output current of each distributed power supply in real time, and the estimation precision is high.
4. The method does not need iterative operation and has high calculation speed.
5. The method fully considers various practical conditions, the differential protection based on the fault components is not influenced by the system load, and the method has high sensitivity.
Drawings
Fig. 1 is a single line diagram of a power distribution network in one embodiment of the invention;
fig. 2 is a flowchart of an adaptive pilot protection method for a power distribution network including an inverter-type distributed power supply according to an embodiment of the present invention.
Detailed Description
It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict, and the present invention is further described in detail with reference to the accompanying drawings and specific embodiments.
Examples
In this embodiment, the power distribution network shown in fig. 1 is taken as an example, where the line impedance is: 0.13+ j 0.356 Ω/km, line M-PCC1、PCC1-PCC2、PCC2-PCC3、PCC3The lengths of N are respectively: 2km, 1km, 3km and 2 km; IBDG1、IBDG2、IBDG3The capacities of the two capacitors are respectively 2MW, 1MW and 3 MW; load LD1、LD2The capacity of (A) is 8+ j0.5MVA, 2 MVA; fault point f1、f2Are respectively positioned in the IBDG2、IBDG3And the end of the bus MN.
An adaptive pilot protection method for a power distribution network with an inverter-type distributed power supply is shown in fig. 2, and comprises the following steps:
(1) powering on a relay protection device;
(2) initializing line parameters;
initializing line parameters includes: initializing rated current of distributed power supply in protection range
Figure BDA0002426705710000061
Initializing line impedance Z between distributed power sources0、Z1、…Zi、…ZnWherein Z is0Is the line impedance between bus M and the 1 st PCC; znIs the line impedance between the nth PCC and bus N; ziIs the line impedance between the ith PCC and the (i + 1) th PCC, wherein i is more than or equal to 1 and less than or equal to n-1.
In this embodiment, the rated current of the distributed power supply in the protection range is initialized
Figure BDA0002426705710000062
The line impedance between the distributed power supplies is Z0＝0.26+j*0.712Ω、Z1＝0.13+j*0.356Ω、Z2＝0.39+j*1.068Ω、Z30.26+ j 0.712 Ω, wherein Z0Is the line impedance between bus M and the first PCC; z1Is the line impedance between the 1 st PCC and the 2 nd PCC; z2Is the line impedance between the 2 nd and 3 rd PCC; z3Is the line impedance between the 3 rd PCC and bus N.
(3) Setting actual rated power capacity S of each distributed power supplyIBDG1＝2MW、SIBDG2＝1MW、SIBDG3＝3MW。
(4) The relay protection devices at the bus M and the bus N respectively sample and convert three-phase voltage and three-phase current before and after the fault of the bus M and the fault of the bus N to obtain positive sequence voltage before the fault of the bus M and the fault of the bus N
Figure BDA0002426705710000071
And fault component voltage vectors of buses M and N
Figure BDA0002426705710000072
And fault component current vector
Figure BDA0002426705710000073
Simultaneously obtaining active power P flowing through buses M and NM、PN；
(5) Setting action threshold delta I 'of fault component current differential protection'IBDG_threAnd a braking coefficient k'resComprises the following steps:
Figure BDA0002426705710000074
Figure BDA0002426705710000075
in the formula，ΔIthre＝KerKstKnpIn，KerFor transmission error of current transformers, KstIs the same type coefficient of mutual inductor, KnpIs a coefficient of a non-periodic component, InRated current flowing through the mutual inductor; kerr0.05 is the maximum error coefficient of the distributed power supply fault component current,
Figure BDA0002426705710000076
rated current of the distributed power supply in a protection range; delta Iu′nbIs the unbalanced fault component current in the case of an out-of-range fault; delta l'r.min＝ΔI'IBDG_thre/kres，kresIs the braking coefficient of a conventional distribution network. In this example,. DELTA.I 'was taken'IBDG_thre＝0.0404kA，k'res＝0.61。
(6) Calculating positive sequence voltage of each PCC before failure
Figure BDA0002426705710000077
Figure BDA0002426705710000078
In the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000079
the positive sequence voltage of the jth PCC when the system normally operates;
Figure BDA00024267057100000710
the positive sequence voltage at two ends of the line MN is obtained when the system normally operates; zM-NAnd ZM-jThe impedance of the line MN and the impedances of M to jth PCCs, respectively, in this embodiment: zM-N＝1.04+j*2.848Ω。
(7) Sum P of output active power of distributed power supply on bus MNoutComprises the following steps:
Figure BDA0002426705710000081
in the formula: poutThe total active power output by the distributed power supply in the line MN when the power grid operates normally is represented; pM、PNActive power flowing through two ends of the line MN respectively; rM-NIs the resistance of line MN. In this example, RM-N1.04 omega
(8) Calculating reference active power P of each distributed power supplyIBDGjComprises the following steps:
Figure BDA0002426705710000082
in the formula, SIBDGjIndicating the installed capacity of the jth distributed power source.
(9) Fault component positive sequence voltage of PCC
Figure BDA0002426705710000083
Comprises the following steps:
Figure BDA0002426705710000084
in the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000085
representing the positive sequence voltage, Z, of the fault component of PCC at node k derived from bus M sideM-jTo be the impedance between bus M and the jth PCC,
Figure BDA0002426705710000086
the calculated value Z of the distributed power supply fault component output current at the jth PCC deduced from the bus M side in the protection rangeM-dIs the impedance between bus M and the d-th PCC.
Distributed power source fault component output current calculated value derived from bus M side at jth PCC
Figure BDA0002426705710000087
The calculation method is as follows:
Figure BDA0002426705710000088
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure BDA0002426705710000089
and
Figure BDA00024267057100000810
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage during the fault deduced from the M side; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting a distributed power supply reference active power; a represents the phase of the distributed power supply output current relative to the voltage before the fault; i represents an imaginary part; rel () represents the calculation of the real part.
Fault component positive sequence voltage of PCC
Figure BDA0002426705710000091
The calculation method is as follows:
Figure BDA0002426705710000092
in the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000093
representing the fault component positive sequence voltage, Z, of PCC at node k derived from the N sideN-jBeing the impedance between bus N and the jth PCC,
Figure BDA0002426705710000094
calculating value Z of distributed power supply fault component output current at jth PCC deduced from N side in protection rangeN-dIs the impedance between bus N and the d-th PCC.
Distributed power supply fault component output current calculated value derived from N side at jth PCC
Figure BDA0002426705710000095
The calculation method is as follows:
Figure BDA0002426705710000096
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure BDA0002426705710000097
and
Figure BDA0002426705710000098
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage during the fault deduced from the N side; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting a distributed power supply reference active power; a represents the phase of the distributed power supply output current relative to the voltage before the fault; i denotes the imaginary part and rel () denotes the real part of the computation.
(10) The calculation mode of the actual fault component positive sequence voltage of each PCC is as follows:
Figure BDA0002426705710000101
in the formula (I), the compound is shown in the specification,
Figure BDA0002426705710000102
a fault component positive sequence voltage actual value of a kth PCC;
Figure BDA0002426705710000103
and
Figure BDA0002426705710000104
and respectively calculating the fault component positive sequence voltage of the kth PCC derived from the side of the bus M and the bus N.
(11) Fault component current estimation for distributed power supplies
Figure BDA0002426705710000105
The calculation method is as follows:
Figure BDA0002426705710000106
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure BDA0002426705710000107
and
Figure BDA0002426705710000108
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage actual value during the fault; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting the reference active power of the distributed power supply, and alpha representing the phase of the output current of the distributed power supply relative to the voltage before the faultI denotes the imaginary part and rel () denotes the real part of the calculation.
(12) Fault component differential current Δ I 'of line'dAnd braking current delta I'rThe calculation method is as follows:
Figure BDA0002426705710000109
(13) judging fault component differential current delta I'dWhether or not to be simultaneously greater than k'resΔI'rAnd Δ I'IBDG_threIf yes, judging the fault in the area and starting a protection action; otherwise, no intra-zone fault is indicated, and the step (4) is returned.
Two different fault types are listed below for illustration:
case 1: in the protective zone f1When an A-phase grounding short circuit fault occurs, the transition resistance is 1 omega, and the effective value of the three-phase voltage measured by the relay protection device at the bus M before the fault is as follows: 5.740-1.137 degrees (kV), 5.740-121.011 degrees (kV) and 5.740-0118.120 degrees (kV), and the effective value of the three-phase current is as follows: 0.230 < 1-9.971 degrees (kA), 0.230 < 2-129.412 degrees (kA) and 0.231 < 3110.521 degrees (kA). The effective value of the three-phase voltage measured by the relay protection device at the position of the bus N before the fault is as follows: 5.244-9.974 degrees (kV), 5.244-130.211 degrees (kV) and 5.242-6109.936 degrees (kV), and the effective value of the three-phase current is as follows: 0.420 angle 7166.399 degree (kA), 0.421 angle 845.843 degree (kA) and 0.422-73.211 degree (kA). The effective value of the three-phase voltage measured by the relay protection device at the bus M during fault is as follows: 2.553-916.044 degrees (kV), 7.241-147.201 degrees (kV) and 8.550-0134.122 degrees (kV), and the effective value of the three-phase current is as follows: 1.151 < 1-25.785 degrees (kA), 0.328 < 2-160.441 degrees (kA) and 0.455 < 137.531 degrees (kA). The effective value of the three-phase voltage measured by the relay protection device at the position of the bus N during fault is as follows: 1.236-28.561 degrees (kV), 6.577-156.325 degrees (kV), 7.799-123.412 degrees (kV), and the effective value of three-phase current is as follows: 0.099 & lt 147.261 ° (kA), 0.523 & lt 19.482 ° (kA), 0.629 & lt-59.592 ° (kA). From the above data,. DELTA.I 'can be obtained'd＝1.282kA，k'resΔI'r0.581 kA. Due to delta I'dIs simultaneously more than k'resΔI'rAnd Δ I'IBDG_threAnd protecting the action.
Case 2: in the protective zone f2When a three-phase grounding short circuit fault occurs, the transition resistance is 100 omega, and the effective value of the three-phase voltage measured by the relay protection device at the bus M before the fault is as follows: 5.740-1.137 degrees (kV), 5.740-121.011 degrees (kV) and 5.740-0118.120 degrees (kV), and the effective value of the three-phase current is as follows: 0.230 < 1-9.971 degrees (kA), 0.230 < 2-129.412 degrees (kA) and 0.231 < 3110.521 degrees (kA). The effective value of the three-phase voltage measured by the relay protection device at the position of the bus N before the fault is as follows: 5.244-9.974 degrees (kV), 5.244-130.211 degrees (kV) and 5.242-6109.936 degrees (kV), and the effective value of the three-phase current is as follows: 0.420 angle 7166.399 degree (kA), 0.421 angle 845.843 degree (kA) and 0.422-73.211 degree (kA). The effective value of the three-phase voltage measured by the relay protection device at the bus M during fault is as follows: 5.737-9.203 degrees (kV), 5.737-121.241 degrees (kV) and 5.737-0118.674 degrees (kV), and the effective value of the three-phase current is as follows: 0.271 & lt 1-11.461 ° (kA), 0.270 & lt 2-131.116 ° (kA) and 0.271 & lt 107.724 ° (kA). The effective value of the three-phase voltage measured by the relay protection device at the position of the bus N during fault is as follows: 5.167-11.402 degrees (kA), 5.168-131.411 degrees (kA) and 5.167-137.531 degrees (kA), wherein the effective value of the three-phase current is as follows: 0.414 < 165.024 ° (kA), 0.414 < 44.694 ° (kA) and 0.414 < 75.063 ° (kA). From the above data,. DELTA.I 'can be obtained'd＝0.0486kA，k'resΔI'r0.0225 kA. Due to delta I'dIs simultaneously more than k'resΔI'rAnd Δ I'IBDG_threAnd protecting the action.
The invention judges the fault position by adopting the mode of differential comparison of the fault component current of each end of the line, is suitable for grid-connected operation of the high-permeability distributed power supply, can reliably act under different positions, different fault types and transition resistances, and has good engineering practical value.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (9)

1. A self-adaptive pilot protection method for a power distribution network containing an inverter type distributed power supply is characterized by comprising the following steps:
s1, powering on the relay protection device;
s2, initializing line parameters;
s3, setting the installed capacity of each distributed power supply;
s4, respectively sampling and converting three-phase voltage and three-phase current before and after the fault of the bus M and the bus N by the relay protection devices at the bus M and the bus N to obtain positive sequence voltage vectors before the fault of the bus M and the fault of the bus N
Figure FDA0002949645930000011
And fault component voltage vectors of bus M and bus N
Figure FDA0002949645930000012
And fault component current vector
Figure FDA0002949645930000013
Simultaneously obtaining active power P flowing through a bus M and a bus NM、PN；
S5, setting operation threshold delta I 'of fault component current differential protection'IBDG_threAnd a braking coefficient k'res；
Action threshold delta I 'of fault component current differential protection'IBDG_threAnd a braking coefficient k'resThe calculation method is as follows:
Figure FDA0002949645930000014
Figure FDA0002949645930000015
in the formula,. DELTA.Ithre＝KerKstKnpIn，KerIs an electric currentTransmission error of mutual inductor, KstIs the same type coefficient of mutual inductor, KnpIs a coefficient of a non-periodic component, InRated current flowing through the mutual inductor; kerrFor the distributed power supply fault component current maximum error coefficient,
Figure FDA0002949645930000016
rated current of the distributed power supply in a protection range; delta l'unbIs the unbalanced fault component current in the case of an out-of-range fault; delta l'r.min＝ΔI'IBDG_thre/kres，kresThe braking coefficient of a conventional power distribution network;
s6, deducing the positive sequence voltage of each PCC before the fault according to the positive sequence voltage vectors before the fault of the bus M and the bus N
Figure FDA0002949645930000017
S7, calculating the sum P of the output active power of the distributed power supply on the line MNout；
S8, distributing according to the ratio of the installed capacity of each distributed power supply to the total capacity of the distributed power supplies on the line MN to obtain the reference active power of each distributed power supply;
s9, respectively deducing the fault component positive sequence voltage of each PCC by the relay protection devices at the bus M and the bus N
Figure FDA0002949645930000018
Obtaining actual fault component positive sequence voltage of each PCC;
s10, calculating the estimated value of the fault component current of each distributed power supply according to the positive sequence voltage of each PCC before the fault, the reference active power of each distributed power supply and the actual fault component positive sequence voltage of each PCC
Figure FDA0002949645930000019
S11, current vector according to fault component
Figure FDA0002949645930000021
And fault component current estimates for distributed power sources
Figure FDA0002949645930000022
Calculating fault component differential current delta I 'of line'dAnd braking current delta I'r；
S12, judging fault component differential current delta I'dWhether or not to be simultaneously greater than k'resΔI'rAnd Δ I'IBDG_threIf yes, judging the fault in the area and starting a protection action; otherwise, no intra-zone fault is indicated, and the process returns to step S4.
2. The adaptive pilot protection method of claim 1, wherein the positive sequence voltage of each PCC prior to the fault
Figure FDA0002949645930000023
The calculation method is as follows:
Figure FDA0002949645930000024
in the formula (I), the compound is shown in the specification,
Figure FDA0002949645930000025
the positive sequence voltage of the jth PCC when the system normally operates;
Figure FDA0002949645930000026
the positive sequence voltage vector is the positive sequence voltage vector before the fault of the bus M and the bus N; zM-NAnd ZM-jRespectively the impedance of the line MN and the impedances of the bus M to the jth PCC.
3. The adaptive pilot protection method of claim 2, wherein the sum P of the output active power of the distributed power supplies on the line MN is the sum of the output active power PoutThe calculation method is as follows:
Figure FDA0002949645930000027
in the formula: poutThe total active power output by the distributed power supply in the line MN when the power grid operates normally is represented; pM、PNRespectively the active power flowing through the bus M and the bus N; rM-NIs the resistance of line MN.
4. The adaptive pilot protection method according to claim 3, wherein the reference active power P of each distributed power supplyIBDGjThe calculation method is as follows:
Figure FDA0002949645930000028
in the formula, SIBDGjRepresenting the installed capacity of the jth distributed power source; n is the total number of distributed power sources.
5. The adaptive pilot protection method of claim 4,
Figure FDA0002949645930000029
the calculation method is as follows:
Figure FDA00029496459300000210
in the formula (I), the compound is shown in the specification,
Figure FDA00029496459300000211
represents the fault component positive sequence voltage of the PCC at node k derived from the bus M side; zM-jIs the impedance between bus M and the jth PCC; zM-dIs the impedance between bus M and the d-th PCC; n is the total number of distributed power supplies;
Figure FDA0002949645930000031
to protect the scopeThe distributed power source fault component output current calculation value at the jth PCC internally derived from the bus M side,
Figure FDA0002949645930000032
the calculation method is as follows:
Figure FDA0002949645930000033
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure FDA0002949645930000034
and
Figure FDA0002949645930000035
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage during the fault deduced from the M side; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting a distributed power supply reference active power; a represents the phase of the distributed power supply output current relative to the voltage before the fault; i represents an imaginary part; rel () represents the calculation of the real part.
6. The adaptive pilot protection method of claim 5,
Figure FDA0002949645930000036
the calculation method is as follows:
Figure FDA0002949645930000037
in the formula (I), the compound is shown in the specification,
Figure FDA0002949645930000038
represents the fault component positive sequence voltage of PCC at node k derived from bus N side; zN-jIs the impedance between bus N and the jth PCC; zN-dIs the impedance between bus N and the d-th PCC; n is the total number of distributed power supplies;
Figure FDA0002949645930000039
the calculated value of the distributed power source fault component output current at the jth PCC derived from the N side of the bus in the protection range,
Figure FDA00029496459300000310
the calculation method is as follows:
Figure FDA0002949645930000041
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Representing an initial phase of a common vector of PCC voltages before a fault;
Figure FDA0002949645930000042
and
Figure FDA0002949645930000043
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage during the fault deduced from the N side; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjRepresenting a distributed power supply reference active power; a represents the phase of the distributed power supply output current relative to the voltage before the fault; i denotes the imaginary part and rel () denotes the real part of the computation.
7. The adaptive pilot protection method of claim 6, wherein the actual fault component positive sequence voltage of each PCC is calculated by:
Figure FDA0002949645930000044
in the formula (I), the compound is shown in the specification,
Figure FDA0002949645930000045
a fault component positive sequence voltage actual value of a kth PCC;
Figure FDA0002949645930000046
and
Figure FDA0002949645930000047
and respectively calculating the fault component positive sequence voltage of the kth PCC derived from the side of the bus M and the bus N.
8. The adaptive pilot protection method of claim 7, wherein a fault component current estimate for the distributed power source at the jth PCC is
Figure FDA0002949645930000048
The calculation method is as follows:
Figure FDA0002949645930000051
in the formula,. DELTA.IdAnd Δ IqD-axis and q-axis components representing the IBDG fault component current, respectively; delta represents the initial phase of the PCC voltage universal vector when the system fails; delta0Indicating PC before failureThe initial phase of the C voltage universal vector;
Figure FDA0002949645930000052
and
Figure FDA0002949645930000053
respectively representing the jth PCC positive sequence voltage before the fault and the jth PCC fault component positive sequence voltage actual value during the fault; kmaxRepresents the maximum current coefficient; i isNRepresents the rated current of the IBDG; kGerRepresenting the voltage support coefficient of Germany LVRT, and K when the voltage change of the grid-connected point is less than 10 percentGerIs 0, more than 10% of KGerIs 2; u represents the fault positive sequence voltage amplitude, Pref＝PIBDGjThe reference active power of the distributed power supply is represented, alpha represents the phase of the output current of the distributed power supply relative to the voltage before the fault, i represents an imaginary part, and rel () represents a real part of calculation.
9. The adaptive pilot protection method of claim 8, wherein a fault component differential current Δ l 'of a line'dAnd braking current delta I'rThe calculation method is as follows:
Figure FDA0002949645930000054
CN202010222925.6A 2020-03-26 2020-03-26 Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply Active CN111313389B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010222925.6A CN111313389B (en) 2020-03-26 2020-03-26 Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010222925.6A CN111313389B (en) 2020-03-26 2020-03-26 Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply

Publications (2)

Publication Number Publication Date
CN111313389A CN111313389A (en) 2020-06-19
CN111313389B true CN111313389B (en) 2021-05-14

Family

ID=71162513

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010222925.6A Active CN111313389B (en) 2020-03-26 2020-03-26 Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply

Country Status (1)

Country Link
CN (1) CN111313389B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112018735B (en) * 2020-08-12 2022-08-16 国网山东省电力公司电力科学研究院 Power differential protection method and system for power distribution network with high-permeability distributed power supply
CN117837040A (en) * 2021-08-25 2024-04-05 西门子公司 Fault level adjustment for converter-based resource (IBR) optimization based on fault location

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103490394A (en) * 2013-09-30 2014-01-01 山东大学 Self-synchronizing positive sequence fault component current differential protection method of active power distribution network
CN105811382A (en) * 2016-03-24 2016-07-27 国网山东省电力公司枣庄供电公司 Positive sequence impedance differential protection method with braking characteristic for power distribution network containing inverter-based distributed generation (IBDG)
CN107104421A (en) * 2017-04-13 2017-08-29 华南理工大学 A kind of voltage longitudinal protection method of distribution network comprising inverse distributed power

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102904225B (en) * 2012-10-08 2014-11-12 华南理工大学 Pilot protection method for distribution network with distributed power supply
CN105762777B (en) * 2016-04-21 2018-06-22 华南理工大学 A kind of longitudinal protection method that inverse distributed power power distribution network is connect containing more T
CN108023338B (en) * 2017-11-28 2019-02-26 国网浙江省电力公司台州供电公司 The judgment method of differential protection for multiterminal T connection electric transmission line
CN109066621B (en) * 2018-08-29 2020-02-21 杭州电力设备制造有限公司 Fault current calculation method, system and equipment for active power distribution network

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103490394A (en) * 2013-09-30 2014-01-01 山东大学 Self-synchronizing positive sequence fault component current differential protection method of active power distribution network
CN105811382A (en) * 2016-03-24 2016-07-27 国网山东省电力公司枣庄供电公司 Positive sequence impedance differential protection method with braking characteristic for power distribution network containing inverter-based distributed generation (IBDG)
CN107104421A (en) * 2017-04-13 2017-08-29 华南理工大学 A kind of voltage longitudinal protection method of distribution network comprising inverse distributed power

Also Published As

Publication number Publication date
CN111313389A (en) 2020-06-19

Similar Documents

Publication Publication Date Title
CN109494697B (en) Cosine similarity-based new energy station multi-end pilot protection method
Haileselassie et al. Power flow analysis of multi-terminal HVDC networks
CN111313389B (en) Self-adaptive pilot protection method for power distribution network containing inverter type distributed power supply
CN108872799B (en) Active power distribution network fault section positioning method and system based on positive sequence current fault component
CN105762777B (en) A kind of longitudinal protection method that inverse distributed power power distribution network is connect containing more T
CN110880743B (en) Kendel rank correlation-based pilot protection method for outgoing line of wind power plant
CN105467273A (en) Novel polarization criteria realization method in non-unit distance protection
Likhitha et al. Setting free fault location for three-terminal hybrid transmission lines connected with conventional and renewable resources
Chang et al. A single-ended fault location method for grid-connected converter system based on control and protection coordination
CN112217183B (en) MMC-HVDC converter station alternating current connecting line distance protection method under interphase short circuit fault
CN113054661A (en) New energy station outgoing line pilot protection method based on Kaemphrara distance
Paladhi et al. Adaptive distance protection for multi-terminal lines connecting converter-interfaced renewable energy sources
CN110165644B (en) New energy station pilot protection method based on transient current time-frequency characteristics
CN109286178B (en) Self-adaptive current protection setting method for power distribution network containing inverter type distributed power supply
George et al. Distance protection issues with renewable power generators and possible solutions
CN108599226B (en) True bipolar MMC-HVDC system line overload emergency control method
Li et al. Improved distance protection for wind farm transmission line based on dynamic frequency estimation
CN113659548B (en) Power distribution network pilot protection method and system based on positive sequence fault component energy direction
Cipriano et al. Transient stability evaluation of high penetration of DFIG controlled by DTC and DPC into power systems
Cao et al. The incorporation of generalized VSC MTDC model in AC/DC power system state estimation
Song et al. An effective methodology for short-circuit calculation of power systems dominated by power electronics converters considering unbalanced voltage conditions and converter limits
Chen et al. A new short-circuit calculation method of power system with photovoltaic power sources
George et al. Fault location for multi-terminal tapped lines using synchronized measurements
Kukkala et al. Single ended fault locator for power transmission lines connected with inverter based resources: Problems and mitigation approach
CN117458409A (en) Self-adaptive protection method for distribution network containing distributed power supply based on single-ended quantity

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