CN109327007B - Same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information - Google Patents
Same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information Download PDFInfo
- Publication number
- CN109327007B CN109327007B CN201810910147.2A CN201810910147A CN109327007B CN 109327007 B CN109327007 B CN 109327007B CN 201810910147 A CN201810910147 A CN 201810910147A CN 109327007 B CN109327007 B CN 109327007B
- Authority
- CN
- China
- Prior art keywords
- return
- line
- compensation coefficient
- impedance
- zero sequence
- 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
Links
- 238000000034 method Methods 0.000 title claims abstract description 61
- 230000004224 protection Effects 0.000 claims abstract description 124
- 238000005259 measurement Methods 0.000 claims abstract description 19
- 238000012423 maintenance Methods 0.000 claims abstract description 17
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 12
- 230000009471 action Effects 0.000 claims description 12
- 238000004891 communication Methods 0.000 claims description 8
- 230000006698 induction Effects 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 230000008859 change Effects 0.000 description 8
- 238000009434 installation Methods 0.000 description 7
- 230000007704 transition Effects 0.000 description 7
- 230000003044 adaptive effect Effects 0.000 description 3
- 238000002847 impedance measurement Methods 0.000 description 3
- 101100004933 Arabidopsis thaliana CYP79F1 gene Proteins 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 101100499229 Mus musculus Dhrsx gene Proteins 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000002591 computed tomography Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/006—Calibration or setting of parameters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/40—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to ratio of voltage and current
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information. The method disclosed by the invention comprises the following steps: according to the acquired station domain information, aiming at each loop C in the multiple loops on the same tower j : judging other return lines C of the same tower k Whether the CT above is broken or saturated, wherein k is not equal to j, k is 1, …, m, and m is the total number of loops in the multiple loops in the same tower; if not, determining a zero sequence compensation coefficient according to the first formula
Wherein the zero sequence compensation coefficient
For determining the return line C j Zero sequence impedance applicable to upper ith phase grounding protection
i takes any of the three phases of the ac line A, B, C. The zero sequence compensation coefficient setting method provided by the invention improves the measurement precision of positive sequence impedance in grounding distance protection; the setting workload of the distance relay is reduced; the single-phase grounding protection of the line under the station area condition is realized; the station domain protection operation and maintenance level of the intelligent substation is improved.
Description
Technical Field
The invention relates to the technical field of power grid relay protection, in particular to a same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information.
Background
In a neutral point direct grounding system, ground distance protection is generally employed for correctly reacting to a fault and quickly acting when the system has a single-phase ground fault.
In the current ground distance protection, when calculating the measured impedance, a zero sequence compensation coefficient is usually introduced to correct the measured impedance. The current setting method of the zero sequence compensation coefficient comprises a single-K value setting method, a double-K value setting method, a multi-K value switching method and the like. Under the large background of power grid scale enlargement and structure complication, the workload of setting the zero sequence compensation coefficient is large, and the actual requirements of engineering are difficult to adapt.
On the other hand, in the methods, the value of the zero sequence compensation coefficient is not changed after the computer is installed or maintained and set. And the fixed zero sequence compensation coefficient value is difficult to adapt to the situations of position change of a fault point and change of a loop running mode.
Disclosure of Invention
The invention provides a device and a method for setting zero sequence compensation coefficients of multiple loops of the same tower based on station domain information, aiming at solving the problems that the workload of setting zero sequence compensation coefficients is large or zero sequence compensation coefficient values are difficult to adapt to the position change of a fault point and the operation mode of the loops in the existing ground distance protection of multiple loops of the same tower.
In a first aspect, the invention provides a same-tower multi-loop zero-sequence compensation coefficient method based on station domain information, which includes:
according to the acquired station domain information, aiming at each loop C in the same-tower multi-loop j Wherein the loop C j Each CT above is in normal operation, j is 1, …, and m is the total number of loops in the multiple loops on the same tower:
judging other return lines C of the same tower k Whether the CT on (1) is broken or saturated, wherein k ≠ j, k ≠ 1, …, m, the station domain information includes CT status information of each CT on each loop, the CT status information includes: saturation, disconnection and normal operation;
if not, determining a zero sequence compensation coefficient according to the first formula
Wherein the zero sequence compensation coefficient
For determining the return line C j Zero sequence impedance applicable to ith phase grounding protection
The value of i is any one of three phases of an alternating current circuit A, B, C, and the first formula is as follows:
wherein,
is a return wire C j A positive sequence impedance per unit length of line,
is a return wire C j The negative-sequence impedance per unit length of the line,
is a return wire C j Zero sequence impedance per unit length;
is a return line C j And loop C k Mutual inductance impedance between them;
Further, the method comprises the following steps of,
the station domain information also comprises line state information of each loop, and the line state information comprises normal operation, hanging ground maintenance and shutdown;
if other return lines C of the same tower k The CT status information of any of the above CTs is line break or saturation,according to the return line C k Determines the return line C k And the return line C j Mutual induction value between
In the return line C k When the line state information is normal operation, the mutual inductance action value is determined according to a second formula
Wherein the second formula is:
in the return line C k When the line state information is in hanging ground maintenance, the mutual inductance action value is determined according to a third formula
Wherein the third formula is:
in the return line C k Determining mutual inductance value when the line state information is off
Is zero; and are
According to all other return lines C k And the return line C j Mutual induction value between
Determining the zero sequence compensation coefficient by using a fourth formula
Further, the method comprises the following steps of,
in determining the zero sequence compensation coefficient
Then, according to the obtained station domain information and the zero sequence compensation coefficient
Determining the loop C by using a fifth formula j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The fifth formula is:
wherein,
is the return wire C j The ith phase voltage at which the upper distance protection is located,
is the return wire C j The ith phase current where the upper distance protection is positioned; and are combined
At the positive sequence impedance
When the impedance value is less than the preset impedance value, the return wire C is determined j The ith phase above has a ground fault;
at the positive sequence impedance
When the impedance value is larger than or equal to the preset impedance value, the return wire C is determined j Phase i above operates normally.
Further, the method comprises the following steps of,
in each of the protection periods, the protection period is set to zero,
determining each loop C in the multiple loops on the same tower respectively j Zero sequence compensation coefficient of
And
respectively determine the return lines C j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
And
respectively determining the return lines C j The ith phase above is in normal operation or has a ground fault.
Further, the method comprises the following steps of,
determining the zero sequence compensation coefficient in each protection period
Before, still include:
according to the pre-configuration scheme, each loop C in the multi-loop on the same tower is obtained from the communication channel j Station domain information on the base station, the station domain information including:
return wire C j Three-phase current measurement value, three-phase voltage measurement value and return line C j The line state information of (1).
In a second aspect, the present invention provides a same-tower multi-loop zero-sequence compensation coefficient setting device based on station domain information, including:
a station domain information obtaining module, configured to obtain station domain information in a same-tower multi-loop line, where the station domain information includes CT status information of each CT on each loop line, and the CT status information includes: disconnection, saturation and normal work;
a zero sequence compensation coefficient strategy switching module, configured to switch each loop C in the multiple loops in the same tower according to the acquired station domain information j Wherein the return line C j Each CT above is in normal operation, j is 1, …, and m is the total number of loops in the multiple loops on the same tower:
judging other return lines C of the same tower k Whether the CT above is broken or saturated, wherein k is not equal to j, and k is 1, …, m;
if not, determining a zero sequence compensation coefficient according to the first formula
Wherein the zero sequence compensation coefficient
For determining the return line C j Zero sequence impedance applicable to ith phase grounding protection
The value of i is any one of three phases of an alternating current line A, B, C, and the first formula is as follows:
wherein,
is a return line C j A positive sequence impedance per unit length of line,
is a return wire C j The negative-sequence impedance per unit length of the line,
is a return wire C j Zero sequence impedance per unit length;
is a return line C j And loop C k Mutual inductance impedance between them;
Further, the device is characterized in that the device,
the station domain information also comprises line state information of each loop, and the line state information comprises normal operation, hanging ground maintenance and outage;
the zero sequence compensation coefficient strategy switching module is also used for other return lines C if the same tower k If the CT status information of any CT is broken or saturated, the loop C is selected k Determines the return line C k And the return line C j Mutual induction value between
In the return line C k When the line state information is normal operation, the mutual inductance action value is determined according to a second formula
Wherein the second formula is:
in the return line C k When the line state information is in hanging ground maintenance, the mutual inductance action value is determined according to a third formula
Wherein the third formula is:
in the return line C k The line state information ofDetermining mutual inductance value when stopping operation
Is zero; and are
According to all other return lines C k And the return line C j Mutual induction value between
Determining the zero sequence compensation coefficient by using a fourth formula
Further, the device further comprises:
a positive sequence impedance determination module for determining the zero sequence compensation coefficient
Then, according to the obtained station domain information and the zero sequence compensation coefficient
Determining the loop C by using a fifth formula j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The fifth formula is:
wherein,
is the return wire C j The ith phase voltage at which the upper distance protection is located,
is the return wire C j The ith phase current where the upper distance protection is positioned;
a ground protection determination module for determining the positive sequence impedance
When the impedance value is less than the preset impedance value, the return wire C is determined j The ith phase above has a ground fault; and for applying a positive sequence impedance
When the impedance value is larger than or equal to the preset impedance value, the return wire C is determined j Phase i above operates normally.
Further, the device is characterized in that the device,
in each of the protection periods, the protection period is set to zero,
the zero sequence compensation coefficient strategy switching module is used for respectively determining each circuit C in the multiple circuits on the same tower j Zero sequence compensation coefficient of
The positive sequence impedance determining module is used for respectively determining loop C j The ith phase grounding protection applicable positive sequence impedance at the upper distance protection position
The grounding protection determination module is used for respectively determining the return lines C j The ith phase above is in normal operation or has a ground fault.
Further, the device is characterized in that the device,
in each protection period, determining the zero sequence compensation coefficient at the zero sequence compensation coefficient strategy switching module
Before the start of the operation of the device,
the station domain information acquisition module acquires each loop C in the multi-loop on the same tower from the communication channel according to a pre-configuration scheme j Station domain information on the base station, the station domain information including:
return wire C j Three-phase current measurement value, three-phase voltage measurement value and return line C j The line state information of (1).
The zero sequence compensation coefficient setting method provided by the invention realizes self-adaption and real-time setting of the zero sequence compensation coefficient applicable to each circuit line in the same tower multi-circuit line based on the station domain information provided by the intelligent substation, and is beneficial to realizing accurate and rapid elimination of the single-phase earth fault of the line.
Compared with the prior art, the zero sequence compensation coefficient setting method provided by the invention improves the measurement precision of positive sequence impedance in grounding distance protection; the setting workload of the distance relay is reduced; the single-phase grounding protection of the line under the station area condition is realized; the station domain protection operation and maintenance level of the intelligent substation is improved.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
FIG. 1 is a schematic flow chart of a tuning method according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a tuning device according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a single tower double loop circuit operating mode conversion;
FIG. 4 is a same tower multi-loop simulation model according to an embodiment of the present invention;
FIG. 5 is a comparison graph of the earth distance protection measurement impedance module values when faults occur at different positions of multiple loops of the same tower;
FIG. 6 shows the impedance error of the grounding distance protection measurement when multiple loops of the same tower are in ground fault through different transition resistors.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
In the multiple circuit lines on the same tower, zero sequence mutual inductance exists between three phases of one circuit line and between any two circuit lines, and the zero sequence compensation coefficient of the grounding distance protection is influenced by zero sequence currents of other circuit lines, so that the setting of the zero sequence compensation coefficient in the multiple circuit lines on the same tower has certain difficulty.
At present, for the problem of zero sequence compensation coefficient setting of multi-loop grounding distance protection of the same tower, a K-value fixing method is mostly adopted, and the zero sequence compensation coefficient is not changed after setting, so that the zero sequence compensation coefficient cannot adapt to the position change of a fault point, the change of a multi-loop operation mode, the change of the size of a transition resistor and the like, and the actual requirements of engineering are difficult to meet.
On the other hand, a certain workload exists in the setting of the K value on each line, and the setting workload is further increased in the same-tower multi-loop situation.
The same-tower multi-loop zero-sequence compensation coefficient self-adaptive online setting method based on the station domain information realizes the self-adaptive online setting of the same-tower multi-loop grounding distance protection based on the station domain information.
The method can meet the impedance measurement requirements of ground distance protection in the same-tower double-loop and multi-loop, can adjust the zero-sequence compensation coefficient according to the changes of the operation mode of the line, the changes of the fault position and the like, greatly lightens the setting workload, improves the impedance measurement precision, and increases the flexibility and the applicability of the ground distance protection.
As shown in fig. 1, in each protection period, a same-tower multi-loop zero-sequence compensation coefficient method 100 based on station domain information according to an embodiment of the present invention includes the following steps:
step S101: the station domain information includes CT status information of each CT on each loop, and the CT status information includes: saturation, disconnection and normal operation; the station domain information also comprises line state information of each loop, and the line state information comprises normal operation, hanging ground maintenance and shutdown;
step S102: for each loop C of the multiple loops of the same tower j Wherein the return line C j Each CT on (computed tomography) is a normal workIn the operating state, j is 1, …, m is the total number of the return wires in the multi-return wire in the same tower:
judging other return lines C of the same tower k Whether the CT above is broken or saturated, where k is not equal to j, k is 1, …, m;
if not, go to step S103:
determining a zero sequence compensation coefficient according to a first formula
Wherein the zero sequence compensation coefficient
For determining the return line C j Zero sequence impedance applicable to ith phase grounding protection
The value of i is any one of three phases of an alternating current line A, B, C, and the first formula is as follows:
wherein,
is a return wire C j The positive sequence impedance per unit length of the line,
is a return wire C j The negative-sequence impedance per unit length of the line,
is a return wire C j Zero sequence impedance per unit length;
is a return wire C j And a return line C k Mutual inductance impedance between them;
if not, executing step S104:
if other return lines C of the same tower k If the CT status information of any CT is broken or saturated, the loop C is selected k Determines the return line C k And the return line C j Mutual induction value between
In the return line C k When the line state information is normal operation, the mutual inductance action value is determined according to a second formula
Wherein the second formula is:
in the return line C k When the line state information is in hanging ground maintenance, the mutual inductance action value is determined according to a third formula
Wherein the third formula is:
in the return line C k Determining mutual inductance value when the line state information is off
Is zero; and step S105:
according to all other return lines C k And the return line C j Mutual inductance value between them
Determining the zero sequence compensation coefficient using a fourth equation
Further, the method is used for determining the zero sequence compensation coefficient
Then, according to the obtained station domain information and the zero sequence compensation coefficient
Determining the loop C by using a fifth formula j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The fifth formula is:
wherein,
is the return wire C j The ith phase voltage at which the upper distance protection is located,
is the return wire C j The ith phase current where the upper distance protection is positioned; and are combined
At the positive sequence impedance
When the impedance value is less than the preset impedance value, the loop C is determined j The ith phase above has a ground fault;
at the positive sequence impedance
When the impedance value is larger than or equal to the preset impedance value, the return wire C is determined j Phase i above operates normally.
Further, the method determines each loop C in the multiple loops of the same tower respectively j Zero sequence compensation coefficient of
And
respectively determine the return lines C j The ith phase grounding protection applicable positive sequence impedance at the upper distance protection position
And
respectively determining the return lines C j The ith phase above is in normal operation or has a ground fault.
Further, the method is used for determining the zero sequence compensation coefficient
Before, still include:
according to the pre-configuration scheme, each loop C in the same-tower multi-loop is obtained from the communication channel j Station domain information on the base station, the station domain information including:
return wire C j Three-phase current measurement value, three-phase voltage measurement value and return line C j The line state information of (1).
In a second aspect, as shown in fig. 2, a station-domain information-based same-tower multi-loop zero-sequence compensation coefficient setting apparatus 200 according to an embodiment of the present invention includes:
a station domain information obtaining module 201, configured to obtain station domain information in multiple lines on the same tower, where the station domain information includes CT status information of each CT on each line, and the CT status information includes: disconnection, saturation and normal work;
a zero sequence compensation coefficient strategy switching module 202, configured to, according to the obtained station domain information, target each line C in the multiple lines in the same tower j Wherein the return line C j Each CT above is in a normal operating state, j is 1, …, m is the total number of the loops in the multi-loop on the same tower:
judging other return lines C of the same tower k Whether the CT above is broken or saturated, where k is not equal to j, k is 1, …, m;
if not, determining a zero sequence compensation coefficient according to the first formula
Wherein the zero sequence compensation coefficient
For determining loop C j Zero sequence impedance applicable to ith phase grounding protection
The value of i is any one of three phases of an alternating current circuit A, B, C, and the first formula is as follows:
wherein,
is a return wire C j The positive sequence impedance per unit length of the line,
is a return wire C j The negative-sequence resistance per unit length of the line,
is a return wire C j On a unit lengthZero sequence impedance;
is a return wire C j And a return line C k Mutual inductance impedance between them;
Further, the device is characterized in that the device,
the station domain information also comprises line state information of each loop, and the line state information comprises normal operation, hanging ground maintenance and outage;
the zero sequence compensation coefficient strategy switching module 202 is further configured to, if another loop C of the same tower is available k If the CT status information of any CT is broken or saturated, the loop C is selected k Determines the return line C k And the return line C j Mutual inductance value between them
In the return line C k When the line state information is normal operation, the mutual inductance action value is determined according to a second formula
Wherein the second formula is:
in the return line C k When the line state information is in hanging ground maintenance, the mutual inductance action value is determined according to a third formula
Wherein the third formula is:
in the return line C k Determining mutual inductance value when the line state information is off
Is zero; and are
According to all other return lines C k And the return line C j Mutual inductance value between them
Determining the zero sequence compensation coefficient using a fourth equation
Further, the device further comprises:
a positive sequence impedance determination module 203 for determining the zero sequence compensation coefficient
Then, according to the obtained station domain information and the zero sequence compensation coefficient
Determining the return line C by using a fifth formula j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The fifth formula is:
wherein,
is the return line C j The ith phase voltage at which the upper distance protection is located,
is the return wire C j The ith phase current where the upper distance protection is positioned;
a ground protection determination module 204 for determining the positive sequence impedance
When the impedance value is less than the preset impedance value, the return wire C is determined j The ith phase above has a ground fault; and for applying a positive sequence impedance
When the impedance value is larger than or equal to the preset impedance value, the return wire C is determined j Phase i above operates normally. Further, the device is characterized in that the device,
in each of the protection periods, the protection period is set to zero,
the zero sequence compensation coefficient strategy switching module 202 is configured to determine each loop C in the multiple loops of the same tower respectively j Zero sequence compensation coefficient of
The positive sequence impedance determining module 203 is used for respectively determining the loop C j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The ground protection determining module 204 is configured to determine the return lines C respectively j The ith phase above is in normal operation or has a ground fault.
Further, the device is characterized in that the device,
in each protection period, the zero sequence compensation coefficient is determined by the zero sequence compensation coefficient strategy switching module 202
Before the start of the operation of the device,
the station domain information acquiring module 201 acquires each loop C of the multiple loops on the same tower from the communication channel according to a pre-configured scheme j Station domain information on the base station, the station domain information including:
return wire C j Three-phase current measurement value, three-phase voltage measurement value, and loop C j The line status information of (a).
The following describes the impedance measurement process of ground distance protection in the double-circuit and multi-circuit on the same tower in detail to describe the method for setting zero-sequence compensation coefficients of the multi-circuit on the same tower based on the station domain information.
Under the condition that the station area protection is available, the distance protection arranged on each line can obtain real-time information (including impedance values and current values required by calculating zero sequence compensation coefficient values) of all protections of the whole station (namely the same tower), including conventional electric quantities such as line voltage, current, power and phase angle, and information such as a circuit breaker on-off state, a circuit pressing plate state and a communication channel state, so as to dynamically adjust the zero sequence compensation coefficient.
Specifically, for example, the operating state of the circuit can be judged to be normal operation, hanging maintenance and outage according to the on-off state of the circuit breaker.
Generally, each of the multiple loops on the same tower has the same physical parameters, such as impedance value and line length; and electrical devices, such as distance protection, distance relays, etc., provided with the same number and specifications; the ABC three phases of each return line are all mounted with ground protection devices (also referred to as ground protection). And the intelligent substation acquires and distributes station domain information of each loop in the multiple loops on the same tower in real time in each preset protection period, and implements safe and effective relay protection according to the station domain information.
In the following, two loops of the double loop are denoted as CI and CII, respectively.
The ground distance protection adopts a zero sequence compensation coefficient K to correct a measurement impedance calculation formula.
Under the single-loop occasion, when the A phase of the CI return line has single-phase earth fault, the electrical quantity at the fault point meets the following conditions:
wherein,
in order to be the fault point voltage phasor,
is the fault point current phasor;
sequentially positive sequence voltage, negative sequence voltage and zero sequence voltage at a fault point;
the positive sequence, the negative sequence and the zero sequence current at the fault point are sequentially arranged.
Because the positive sequence network impedance and the negative sequence network impedance are not equal to each other, the positive sequence voltage, the negative sequence voltage and the zero sequence voltage at the protection installation point have the following relationship:
wherein,
is the positive sequence impedance per unit length of the CI line,
is the negative-sequence impedance per unit length of the CI line,
zero sequence impedance of the CI line in unit length; l is the length (or distance) of the line between the protection installation point and the fault point on the CI line.
The two types can be arranged, and the measured A phase voltage phasor at the protective installation point
Comprises the following steps:
if the measured impedance is to be made positive sequence impedance for protecting the line between the installation point and the fault point
Current introduced into the distance relay
Should be connected to the voltage introduced into the distance relay
The following relationship is satisfied:
wherein
Namely the zero sequence compensation coefficient.
On the occasion of double circuit lines, zero sequence mutual inductance exists between CI and CII of the two circuit lines, and the measured voltage of the A-phase voltage measured by the distance relay
The following steps are changed:
wherein,
zero-sequence current on a loop CII;
zero sequence current when A phase earth fault occurs on the return line CI;
the zero sequence mutual inductance impedance of the return line CII and the return line CI is shown.
It should be noted that, a method for determining the zero sequence current on the return line according to the station domain information provided by the intelligent substation, such as the phase current of each phase on each line, is well known to those skilled in the art, and is not described herein again.
Zero sequence compensation factor if the measured impedance still to ensure distance protection is the positive sequence impedance of the line between the protected installation point and the fault point
The strain is:
similarly, in the case of m return lines (m > 2), because zero-sequence mutual inductance exists between all the other (m-1) return lines and the return line CI, if it is still to be ensured that the distance protection measurement impedance on the return line CI is the positive-sequence impedance of the line between the protection installation point and the fault point, the zero-sequence compensation coefficient K is:
usually, a set of distance protection devices including distance relays are respectively arranged on each loop on the bus sides of two sides of the loop.
Taking the distance protection near the bus on one side of the return line CI as an example, the station area information-based method for setting the zero sequence compensation coefficient of the same-tower multi-return line and the distance protection method are described. In particular, the distance protection on the CI line is based on real-time information obtained from the communication line that is monitored by all protection on the tower, including the distance protection on the CI line, e.g.,
and basic parameters on the line (e.g. positive sequence impedance values of the lines)
Zero sequence impedance value
And zero sequence mutual inductance impedance
) Determining zero sequence compensation coefficient applicable to ABC three phases on CI line
And
distance protection on CI line according to A phase voltage
Phase A current
And zero sequence compensation coefficient
Measuring impedance for A-phase earth protection, i.e. positive sequence impedance, for determining the suitability of distance protection on CI lines
At the measuring impedance (i.e. positive sequence impedance)
When the impedance value is smaller than the preset impedance value, judging that the phase A has a ground fault;
at the positive sequence impedance of the measuring impedance
When the impedance value is larger than the preset impedance value, the normal operation of the phase A is judged; or
Further, according to the positive sequence impedance
Determining an A-phase protection distance l suitable for distance protection on a CI line;
when the value l is smaller than a preset impedance value, judging that the phase A has a ground fault;
and when the value l is not less than the preset impedance value, judging that the phase A normally operates.
The above description is given by taking the case where the phase a of the CI return line has an earth fault, and the zero sequence compensation coefficient dynamic adjustment method and the distance protection method adopted in the single-phase earth fault protection are explained. The method for dynamically adjusting the zero sequence compensation coefficient when the phase B or the phase C of the CI loop has a ground fault is similar to the method, and is not described herein again.
The distance protection near the bus bar on the other side on the return line CI is similar to the distance protection arranged on the bus bar side on the one side, and is not described in detail here.
In fig. 3, when S1 and S3 are closed and S2 and S4 are opened, the CII loop is in a normal operation state; closing S1-S4, the CII return wire is in a hanging maintenance state,
by
Induction is carried out; all the S1-S4 are disconnected, so that the CII loop is in a shutdown state, and the CII loop is in a shutdown state
I.e. there is no mutual inductance between the two loops.
By combining the running state of the return line, the feasibility of setting the zero sequence compensation coefficient in real time can be further improved.
Specifically, when the other loops are in CT saturation and disconnection, the operation states of the other loops are judged, and the adjustment is carried out according to the following formula
The values are preset values:
in the formula,
for the influence of other loops on the zero sequence compensation coefficient of the loop, the subscript m represents the loop number, and p represents the running state of the loop with the subscript m.
Taking a double loop as an example, when the other loop is operating normally:
when the other loop is off:
when another loop is overhauled in a hanging mode:
in summary, according to the station area information-based self-adaptive setting method for the zero-sequence compensation coefficients of the multiple loops on the same tower, under the condition that the line operation information provided by other loops is determined to be correct, the self-adaptive on-line setting is performed on the zero-sequence compensation coefficients of the ground distance protection according to the zero-sequence compensation coefficient setting method of the first scheme (i.e. the first formula);
and under the condition that the line operation information provided by other loop lines is wrong, carrying out self-adaptive online setting on the zero sequence compensation coefficient of the grounding distance protection according to the zero sequence compensation coefficient setting method (namely, a fourth formula) of the second scheme.
And switching the adopted zero sequence compensation coefficient setting method according to the running state information of the actual line, thereby further improving the distance protection performance.
The method for setting zero-sequence compensation coefficients of multiple same-tower loops based on station domain information provided by the invention is explained in detail below.
As shown in fig. 4, a PSCAD/EMTDC model is used to simulate a double-circuit line, so that a conventional tuning method using a fixed zero-sequence compensation coefficient and a self-adaptive online calibration method are compared in many aspects to verify the superiority of the method. In fig. 4, the line length is 100km and the system voltage level is 500 kV. The impedance parameters of the line are shown in table 1:
TABLE 1 System parameters of two-circuit simulation model on same tower
When the other loop line is in normal operation, the zero sequence compensation coefficient is obtained
Comprises the following steps:
the method is established on the basis of short circuit at the tail end of a line, the double-circuit structure is symmetrical, zero-sequence currents of CI (common interface) circuits and CII (common interface) circuits are equal, and the formula is established. In practice, it is possible that a fault occurs anywhere on the line, and this assumption does not hold and the error may be large.
Assuming that the distance between the metallic earth fault occurrence point of phase A and the BUS M is different positions such as 10km to 100km, the measured impedance data of the grounding distance protection of the side of the CI line BUS1 is recorded as shown in Table 2:
TABLE 2 impedance and its error measured by earth distance protection in case of fault in different positions of multi-loop line on same tower
The measured impedance mode curves for different values of K in table 2 are shown in fig. 5, which is true.
When an earth fault occurs at a position 10km away from an outlet, the current flowing through the CI loop wire and grounded by the bus M side is increased sharply, and the zero sequence current of the other loop wire is relatively much smaller, so that certain error exists in the measured impedance. When a fault point is close to the middle point of the line, the zero sequence current of the CII return line is greatly reduced, the zero sequence current of the CI return line is almost completely provided by the systems on two sides, and the error is maximum at the moment.
When the fault point is close to the tail end, the line structure approaches to symmetry, zero sequence currents measured by the grounding distance protection of the BUS BUS1 side tend to be consistent, and errors are obviously reduced.
However, no matter where the fault point is, the method of adaptive online tuning using the zero-sequence compensation coefficient is more accurate than the conventional method of using the fixed zero-sequence compensation coefficient in equation (12).
When the fault is non-metal type grounding, the transition resistance can affect the measurement impedance of the grounding distance protection, the large transition resistance can obviously affect the distance protection performance, the fault current can be smaller than the load current when the fault is actually grounded through the 300 omega transition resistance, the traditional distance protection error can exceed 70%, the protection range is greatly shortened, and the protection sensitivity is reduced. Therefore, it is necessary to provide a performance difference between the zero-sequence compensation coefficient adaptive online tuning method and the conventional zero-sequence compensation coefficient method in the presence of the transition resistance.
FIG. 6 shows the measured impedance error when the phase A is grounded through a 0 Ω -70 Ω transition resistor at a distance of 10km from the outlet on the CI loop. Therefore, the zero sequence compensation coefficient self-adaptive online setting method still has obvious advantages compared with the fixed K value method.
Compared with the traditional method, the zero sequence compensation coefficient self-adaptive setting method has the advantage that the zero sequence compensation coefficient of the ground distance protection of the return line can be adjusted in an adaptive online manner according to the running state of other return lines.
Therefore, the errors of the measured impedance obtained by adopting the zero-sequence compensation coefficient self-adaptive online setting method and the traditional setting method under the condition that the A phase is connected with the 30 omega resistor ground fault at the 90km position of the CI loop outlet and the other loop is normally operated, stopped and hung on the ground for maintenance are respectively simulated as shown in the table 3:
TABLE 3 measured impedance error of CI grounding distance relay under different line operation modes
Therefore, when the operation is stopped, the current of the other loop is 0, the influence of zero sequence mutual inductance between the double loops is avoided, and the measured impedance errors are the same. And under other operation modes, the effect of the self-adaptive online positive setting method of the zero sequence compensation coefficient is superior to that of the traditional zero sequence compensation coefficient setting method.
The invention adopts station domain information to realize the self-adaptive on-line setting of the zero sequence compensation coefficient in the grounding distance protection, ensures that the measured impedance of the grounding distance relay can correctly reflect the positive sequence impedance of the line between the protection installation point and the fault point, improves the flexibility, the applicability and the accuracy of the grounding distance protection, and can lighten the setting workload of the grounding distance relay.
The self-adaptive setting method can meet the requirement of a large-scale complex power grid on the ground distance protection performance, is suitable for ground distance protection of the same-tower multi-circuit line, and has good performance under the conditions of fault point change, power grid operation mode change, CT abnormity and the like.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitutions or changes made by the person skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the invention is subject to the claims.
Claims (8)
1. A method for setting zero sequence compensation coefficients of multiple same-tower loops based on station domain information is characterized by comprising the following steps:
according to the acquired station domain information, aiming at each loop C in the multiple loops on the same tower j Wherein the return line C j Each CT above is in a normal operating state, j is 1, …, m is the total number of the loops in the multi-loop on the same tower:
judging other return lines C of the same tower k Whether the CT on (1) is broken or saturated, wherein k ≠ j, k ≠ 1, …, m, the station domain information includes CT status information of each CT on each loop, the CT status information includes: saturation, disconnection and normal operation;
if not, determining a zero sequence compensation coefficient according to the first formula
Wherein the zero sequence compensation coefficient
For determining the return line C j Zero sequence impedance applicable to ith phase grounding protection
The value of i is any one of three phases of an alternating current line A, B, C, and the first formula is as follows:
wherein,
is a return wire C j The positive sequence impedance per unit length of the line,
is a return wire C j The negative-sequence impedance per unit length of the line,
is a return wire C j Zero sequence impedance per unit length;
is a return wire C j And a return line C k Mutual inductance impedance between them;
the station domain information also comprises line state information of each loop, and the line state information comprises normal operation, hanging ground maintenance and shutdown;
if other return lines C of the same tower k If the CT status information of any CT is broken or saturated, then according to the loop C k Determines the loop C k And the return line C j Mutual induction value between
In the return line C k When the line state information is normal operation, the mutual inductance action value is determined according to a second formula
Wherein the second formula is:
in the return line C k When the line state information is in hanging ground maintenance, the mutual inductance action value is determined according to a third formula
Wherein the third formula is:
in the return line C k Determining mutual inductance value when the line state information is off
Is zero; and are
According to all other return lines C k And the return line C j Mutual inductance value between them
Determining the zero sequence compensation coefficient using a fourth equation
2. The method of claim 1,
in determining the zero sequence compensation coefficient
Then, according to the obtained station domain information and the zero sequence compensation coefficient
Determining the return line C by using a fifth formula j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The fifth formula is:
wherein,
is the return line C j The ith phase voltage at which the upper distance protection is located,
is the return wire C j The ith phase current at which the upper distance protection is positioned; and are
At the positive sequence impedance
When the impedance value is less than the preset impedance value, the return wire C is determined j The ith phase above has a ground fault;
at the positive sequence impedance
When the impedance value is larger than or equal to the preset impedance value, the return wire C is determined j Phase i above operates normally.
3. The method of claim 2,
in each of the protection periods, the protection period is set to zero,
determining each loop C in the multiple loops on the same tower respectively j Zero sequence compensation coefficient of
And
respectively determine the return lines C j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
And
respectively determining the return lines C j The ith phase above is in normal operation or has a ground fault.
4. The method of claim 2,
determining the zero sequence compensation coefficient in each protection period
Before, still include:
according to the pre-configuration scheme, each loop C in the multi-loop on the same tower is obtained from the communication channel j Station domain information on the base station, the station domain information including:
return wire C j Three-phase current measurement value, three-phase voltage measurement value and return line C j The line state information of (1).
5. A same-tower multi-loop zero-sequence compensation coefficient setting device based on station domain information is characterized by comprising the following steps:
a station domain information obtaining module, configured to obtain station domain information in a same-tower multi-loop line, where the station domain information includes CT status information of each CT on each loop line, and the CT status information includes: disconnection, saturation and normal work; a zero sequence compensation coefficient strategy switching module, configured to switch each loop C in the multiple loops in the same tower according to the acquired station domain information j Wherein the return line C j Each CT above is in normal operation, j is 1, …, and m is the total number of loops in the multiple loops on the same tower:
judging other return lines C of the same tower k Whether the CT above is broken or saturated, where k is not equal to j, k is 1, …, m;
if not, according to the first stepDetermining zero sequence compensation coefficient by formula
Wherein the zero sequence compensation coefficient
For determining the return line C j Zero sequence impedance applicable to ith phase grounding protection
The value of i is any one of three phases of an alternating current circuit A, B, C, and the first formula is as follows:
wherein,
is a return wire C j The positive sequence impedance per unit length of the line,
is a return line C j The negative-sequence impedance per unit length of the line,
is a return wire C j Zero sequence impedance per unit length;
is a return wire C j And a return line C k Mutual inductance impedance between them;
the station domain information also comprises line state information of each loop, and the line state information comprises normal operation, hanging ground maintenance and outage;
the zero sequence compensation coefficient strategy switching module is also used for switching other return lines C of the same tower if k If the CT status information of any CT is broken or saturated, the loop C is selected k Determines the return line C k And the return line C j Mutual inductance value between them
In the return line C k When the line state information is normal operation, the mutual inductance action value is determined according to a second formula
Wherein the second formula is:
in the return line C k When the line state information is in hanging ground maintenance, the mutual inductance action value is determined according to a third formula
Wherein the third formula is:
in the return line C k Determining mutual inductance value when the line state information is off
Is zero(ii) a And are
According to all other return lines C k And the return line C j Mutual inductance value between them
Determining the zero sequence compensation coefficient using a fourth equation
6. The apparatus of claim 5, further comprising:
a positive sequence impedance determination module for determining the zero sequence compensation coefficient
Then, according to the obtained station domain information and the zero sequence compensation coefficient
Determining the return line C by using a fifth formula j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The fifth formula is:
wherein,
is the return wire C j The ith phase voltage at which the upper distance protection is located,
is the return line C j The ith phase current where the upper distance protection is positioned; and are combined
A ground protection determination module for determining the positive sequence impedance
When the impedance value is less than the preset impedance value, the return wire C is determined j The ith phase above has a ground fault; and for applying a positive sequence impedance
When the impedance value is larger than or equal to the preset impedance value, determining the return wire C j Phase i above operates normally.
7. The apparatus of claim 6,
in each of the protection periods, the protection period is set to zero,
the zero sequence compensation coefficient strategy switching module is used for respectively determining each circuit C in the multiple circuits on the same tower j Zero sequence compensation coefficient of
The positive sequence impedance determining module is used for respectively determining return wires C j The ith phase grounding protection where the upper distance protection is positioned is suitable for positive sequence impedance
The grounding protection determination module is used for respectively determining the return lines C j The ith phase above is in normal operation or has a ground fault.
8. The apparatus of claim 6,
in each protection period, the strategy of the zero sequence compensation coefficient is cutDetermining the zero sequence compensation coefficient by a conversion module
Before the start of the operation of the device,
the station domain information acquisition module acquires each loop C in the multi-loop on the same tower from the communication channel according to a pre-configuration scheme j Station domain information on the base station, the station domain information including:
return wire C j Three-phase current measurement value, three-phase voltage measurement value, and loop C j The line state information of (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810910147.2A CN109327007B (en) | 2018-08-10 | 2018-08-10 | Same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810910147.2A CN109327007B (en) | 2018-08-10 | 2018-08-10 | Same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109327007A CN109327007A (en) | 2019-02-12 |
| CN109327007B true CN109327007B (en) | 2022-09-20 |
Family
ID=65264004
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810910147.2A Active CN109327007B (en) | 2018-08-10 | 2018-08-10 | Same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109327007B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110187266B (en) * | 2019-05-31 | 2021-07-06 | 深圳供电局有限公司 | Ground impedance relay fault detection method, computer device, and storage medium |
| CN112630587A (en) * | 2020-11-11 | 2021-04-09 | 大唐水电科学技术研究院有限公司 | Single-circuit three-phase disconnection fault analysis method for four-circuit line erected on same pole |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102096020B (en) * | 2010-11-25 | 2013-06-12 | 国家电网公司 | Relay protection malfunction distance measuring and calibrating method of electric power system |
| CN104253421B (en) * | 2014-09-28 | 2017-07-25 | 中国南方电网有限责任公司 | A kind of common-tower double-circuit lines relay protection Optimal Configuration Method shared based on station domain information |
| CN107623311B (en) * | 2017-09-19 | 2019-04-19 | 国家电网公司华中分部 | Adjust the method and device of the zero sequence current compensation factor setting valve of double loop |
| CN107968384B (en) * | 2017-10-20 | 2022-04-05 | 中国电力科学研究院有限公司 | Same-pole multi-loop zero-sequence current protection method and device |
-
2018
- 2018-08-10 CN CN201810910147.2A patent/CN109327007B/en active Active
Non-Patent Citations (1)
| Title |
|---|
| 特高压同塔双回线路零序电流补偿系数整定;周春霞等;《电网技术》;20121231;第36卷(第12期);正文第106-111页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109327007A (en) | 2019-02-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yip et al. | Dynamic line rating protection for wind farm connections | |
| Nunes et al. | Impedance-based fault location formulation for unbalanced primary distribution systems with distributed generation | |
| Du et al. | Online estimation of power transmission line parameters, temperature and sag | |
| CN104345197A (en) | Method and apparatus for estimating angle of zero sequence voltage in single-phase grounding fault | |
| CN102224427A (en) | Method and apparatus for detecting a phase-to-earth fault | |
| JP2014163928A (en) | Method and system for locating fault in ungrounded power distribution system | |
| Dzafic et al. | Impedance based fault location for weakly meshed distribution networks | |
| CN103529356B (en) | For the method and apparatus determining the distance from relatively fault | |
| CN101106047A (en) | A single phase grounding failure relay protection method based on negative electrical impedance relay | |
| EP2770600B1 (en) | Method and system for determining power consumption of loads | |
| CN111781461B (en) | Ground fault line selection and section determination method for small-current grounding power system | |
| CN106941252B (en) | It is not required to the guard method of distribution feeder containing DG of voltage | |
| CN109327007B (en) | Same-tower multi-circuit zero-sequence compensation coefficient setting device and method based on station domain information | |
| Makwana et al. | Transmission line protection using digital technology | |
| CN109001592A (en) | A kind of resonant earthed system fault line selection method for single-phase-to-ground fault based on transient | |
| CN102959413A (en) | Method and apparatus for determining distance to phase-to-earth fault | |
| CN109188205A (en) | A kind of distance measuring method of the distance protection based on petal type power grid | |
| CN106026069A (en) | Distribution network capacitive current distribution compensation method | |
| CN102004191A (en) | Method for calculating line capacitance in arc suppression coil parallel running system | |
| CN106469905B (en) | Distribution network protection method based on distribution network three-way defense line | |
| Samkari et al. | Modeling and simulation the impacts of STATCOMs on distance protection | |
| CN104730417B (en) | It is a kind of using negative-sequence current as the transmission line of electricity method of single end distance measurement of amount of polarization | |
| CN104749453A (en) | Method for reducing influences imposed on user voltage sag by external grid single-phase grounding fault | |
| CN114825285A (en) | Device, system, and method for performing two-port equivalent online updates | |
| CN108666985B (en) | Accurate diagnosis and protection method for power frequency overvoltage of power transmission line |
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 |