CN109861180B - Bus differential protection locking spare power automatic switching protection method for preventing dead zone fault of sectional breaker - Google Patents
Bus differential protection locking spare power automatic switching protection method for preventing dead zone fault of sectional breaker Download PDFInfo
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- CN109861180B CN109861180B CN201910261119.7A CN201910261119A CN109861180B CN 109861180 B CN109861180 B CN 109861180B CN 201910261119 A CN201910261119 A CN 201910261119A CN 109861180 B CN109861180 B CN 109861180B
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Abstract
The invention discloses a bus differential protection locking spare power automatic switching protection method for preventing dead zone faults of a sectional breaker, and solves the technical problem that in the prior art, spare power automatic switching is locked no matter a first-section bus fault or a second-section bus fault exists, namely, a corresponding locking scheme is not adopted, and all power failures of a whole station are easily caused. The invention adopts the scheme of 110kV bus differential protection locking spare power automatic switching of the substation, can correctly act to lock the action of the spare power automatic switching and switch on the switch under various operation modes and when each 110kV bus has a fault, prevents the spare power automatic switching from being mistakenly switched on fault equipment, and is favorable for the safe and stable operation of a power grid. When the dead zone fault of the subsection (bus coupling), the 110kV bus differential protection can accurately act to remove the fault. The invention adopts the scheme of 110kV bus differential protection locking spare power automatic switching of the substation, can not mistakenly lock the spare power automatic switching action and switch on when the 110kV outgoing line fails in various operation modes, and improves the power supply reliability of a power grid.
Description
Technical Field
The invention relates to a bus differential protection locking spare power automatic switching protection method for preventing dead zone faults of a sectional breaker, and belongs to the technical field of power transmission and distribution network control.
Background
At present, there are 2 methods for protecting the locking 110kV standby power supply automatic switching device (backup automatic switching for short) at the 110kV side of the 110kV single-bus sectional wiring substation: (1) adopting a 110kV power supply to carry out wire inlet protection; (2) and 110kV bus differential protection is adopted. The 110kV incoming line protection locking 110kV spare power automatic switching scheme has the following problems: 1. when an outgoing line exists on a 110kV I section bus or a 110kV II section bus, and the outgoing line is in fault, the incoming line protection of the 110kV power supply cannot judge whether the 110kV line is in fault or the 110kV bus is in fault; 2. when one power supply inlet line runs with two buses, the 110kV power supply inlet line protection cannot judge whether a 110kV I section bus or a 110kV II section bus fails under the condition that any bus fails; the two problems are that the problem that the 110kV power supply incoming line protection locking 110kV spare power automatic switching is difficult to solve. The 110kV bus differential protection is adopted as the 110kV bus protection to lock the 110kV spare power automatic switching scheme, so that the following problems exist: according to the specification of Q/GDW 10767 and 2015, the locking backup power automatic switching is realized by adopting 110kV bus differential protection, and only 1 pair of trip contacts are output to the backup power automatic switching. By doing so, the existing 110kV bus differential protection locking 110kV spare power automatic switching scheme exists: no matter I section bus fault or II section bus faults, the spare power automatic switching device is locked, namely, a corresponding locking scheme is not adopted, and the whole power failure of the total station is easily caused. The invention provides a technical scheme of relay protection of 110kV busbar differential protection blocking spare power automatic switching of 110kV single-bus sectional wiring aiming at dead zone faults of a section breaker of a substation.
Disclosure of Invention
The invention aims to provide a busbar differential protection locking spare power automatic switching protection method for preventing dead zone faults of a segmented circuit breaker, and solves the technical problem that in the prior art, no matter a first-section bus fault or a second-section bus fault is caused, the spare power automatic switching is locked, namely, a corresponding locking scheme is not adopted, and all power failures of a whole station are easily caused.
The purpose of the invention is realized by the following technical scheme:
a bus differential protection locking backup power automatic switching protection method for preventing dead zone faults of a sectional breaker comprises the following steps:
1. the bus differential protection action is taken to jump I section bus circuit breaker and is blocked 1 power circuit breaker control of closing a floodgate simultaneously:
1.1 blocking Condition 1
(1) The 110kV I section bus composite voltage is locked and opened;
(2) a 110kV bus differential I section bus small differential relay containing sectional current acts;
(3) the 110kV bus differential large differential relay acts;
when the conditions are met, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
1.2 blocking Condition 2
(1) The 110kV I section bus composite voltage is locked and opened;
(2) a 110kV bus differential I section bus small differential relay without sectional current acts;
(3) the 110kV bus differential large differential relay acts;
(4) the sectional breaker is at the opening position;
when the conditions are met, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
1.3 blocking Condition 3
1.3.1 output T time open signal
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) a 110kV bus difference II-section bus small differential relay with sectional current acts;
(3) the 110kV bus differential large differential relay acts;
when the conditions (1) to (3) are all met, outputting a T time open signal;
1.3.2 latch-up conditions:
(1) when any condition of the conditions (1) to (3) of the 1.3.1 is not met, namely a 110kV bus differential II section bus small differential relay or a 110kV bus differential large differential relay or a 110kV II section bus composite voltage element is changed from the original action to return;
(2) there is an output T time open signal;
(3) when the section breaker is changed from the switching-on position to the switching-off position;
(4) the 110kV bus differential II-section bus small differential relay without sectional current does not act;
(5) the 110kV I section bus composite voltage is locked and opened;
(6) the 110kV bus differential large differential relay acts;
(7) the phase current element of the segmented CT exceeds a setting value, or the zero-sequence current element exceeds the setting value;
when the conditions are all met, after delay time t1, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
1.3 blocking Condition 4
(1) The 110kV I section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) the spare power automatic switching starts a No. 1 power incoming line breaker 1DL to switch on;
(4) the No. 1 power incoming line breaker 1DL is changed from an opening position to a closing position;
(5) the phase current element of the inlet wire of the No. 1 power supply exceeds a setting value, or the zero-sequence current element exceeds the setting value;
when the conditions are all met, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
2. the control that the bus differential protection action jumps II sections of bus circuit breakers and locks No. 2 power circuit breakers to switch on simultaneously is as follows:
2.1 blocking Condition 1
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) a 110kV bus difference II-section bus small differential relay with sectional current acts;
(3) the 110kV bus differential large differential relay acts;
when the conditions are met, the bus differential protection action tripping II-section bus circuit breaker simultaneously locks the No. 2 power circuit breaker to be switched on;
2.2 blocking Condition 2
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) a 110kV bus differential II-section bus small differential relay without sectional current acts;
(3) the 110kV bus differential large differential relay acts;
(4) the sectional breaker is at the opening position;
when the conditions are met, the bus differential protection action tripping II-section bus circuit breaker simultaneously locks the No. 2 power circuit breaker to be switched on;
2.3 blocking Condition 3
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) the spare power automatic switching starts a No. 2 power incoming line breaker 2DL to switch on;
(4) the No. 2 power incoming line breaker 2DL is changed from an opening position to a closing position;
(5) the phase current element of the inlet wire of the No. 2 power supply exceeds a setting value, or the zero-sequence current element exceeds the setting value;
when the conditions are all met, the bus differential protection action tripping II-section bus circuit breaker simultaneously locks the No. 2 power circuit breaker to be switched on;
3. the control of the closing of the bus differential protection action locking section breaker is as follows:
3.1 blocking Condition 1:
(1) the 110kV I section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) a 110kV bus differential I section bus small differential relay containing sectional current acts;
when the conditions are met, the bus differential protection action tripping sectional circuit breaker locks the sectional circuit breaker to be switched on at the same time;
3.2 blocking Condition 2:
(1) the 110kV II-section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) a 110kV bus difference II-section bus small differential relay with sectional current acts;
when the conditions are met, the bus differential protection action tripping sectional circuit breaker locks the sectional circuit breaker to be switched on at the same time;
3.3 blocking Condition 3:
(1) the 110kV bus differential large differential relay acts;
(2) the composite voltage of the 110kV I section bus is locked and unlocked or the composite voltage of the 110kV II section bus is locked and unlocked;
and when the conditions are met, the bus differential protection action tripping sectional breaker locks the sectional breaker to be switched on at the same time.
The object of the invention can be further achieved by the following technical measures:
according to the bus differential protection locking backup power automatic switching protection method for preventing the dead zone fault of the segmented circuit breaker, the T time in the output T time opening signal is 200-300 milliseconds; the delay time t1 takes 20-40 milliseconds.
According to the bus differential protection locking spare power automatic switching protection method for preventing the dead zone fault of the segmented circuit breaker, the setting and requirements of related protection in locking conditions 1 and 2 are as follows:
1. in the locking conditions 1 and 2, the phase current element fixed value of the subsection or the inlet wire of the No. 1 power supply or the inlet wire of the No. 2 power supply is set according to the maximum short-circuit current which flows through the protection when the middle and low-voltage buses of the transformer substation on the local substation or the 110kV outlet line are short-circuited:
(1) in the formula (I), the compound is shown in the specification,
the maximum short-circuit current K of the protection flows when the middle and low-voltage buses of the maximum transformer of the substation or the substation on a 110kV outgoing line are short-circuited in the maximum operation mode of the systemkTaking 1.3-1.5 as a reliable coefficient;
the zero sequence current element fixed value of the section or No. 1 power supply inlet wire has sensitivity setting more than or equal to 1.5 times according to the minimum operation mode of the system for 110kV bus single-phase earth fault:
(2) in the formula (I), the compound is shown in the specification,
is 110kV bus single-phase short-circuit current in the minimum operation mode of the system, KlmTaking 1.5 as a sensitivity coefficient;
2. phase current elements of a segmented or No. 1 power supply inlet wire or No. 2 power supply inlet wire adopt phase currents of an A phase, a B phase and a C phase;
the phase current element and the zero sequence current element of No. 3.1 power supply incoming line or No. 2 power supply incoming line are required to be provided with a direction element, and the direction element points to: pointing from the line to the bus bar.
According to the bus differential protection locking backup power automatic switching protection method for preventing the dead zone fault of the segmented circuit breaker, the protection configuration and setting requirements of the power side line of the upper-level transformer substation are as follows:
1. protection configuration requirements of power supply side line of upper-level transformer substation
The power supply circuit of the superior transformer substation is provided with optical fiber current differential protection, phase distance I-III section protection, grounding distance I-III section protection, zero sequence current I-III section protection and reclosing;
when the power line is a short line less than or equal to 5km, the power line of the superior substation must be configured and set with optical fiber current differential protection.
2. Protection setting requirement of power supply side line of upper-level transformer substation
Wherein I section of zero sequence current is stopped using, I section of protection of interphase distance, I section of grounding distance and II section of protection of interphase distance, II sections of grounding distance and II sections of zero sequence current have the setting requirements as follows:
(1) protection of phase distance I section and grounding distance I section
Setting according to the condition of avoiding the tail end fault of the line:
Zzd≤KKZL(3)
(3) in the formula KKTaking 0.7-0.8 as a reliable coefficient;
the time delay of the protection of the interphase distance I section and the grounding distance I section is 0 s;
when the power supply line is a short line less than or equal to 5km, the protection of the interphase distance I section and the grounding distance I section is stopped when the protection cannot be set, and the protection function is served by optical fiber current differential protection with a full-line quick-action function;
(2) protection of interphase distance II section and grounding distance II section
Setting the minimum measurement impedance of the protection when the medium-low voltage bus of the maximum transformer of the substation or the 110kV outgoing line is in short circuit:
Zzd≤KKZL+KKbZb(4)
(4) in the formula KK、KKbTaking the coefficient of reliability as 0.7-0.8, ZLIs line impedance, ZbIs the transformer impedance;
the time delay of the protection of the interphase distance II section and the grounding distance II section is 0.3 s;
(3) zero sequence current II section
Setting according to the fact that the line tail end fault has enough sensitivity:
(5) in the formula (II), the compound is shown in the specification,
is 110kV bus single-phase short-circuit current in the minimum operation mode of the system, KlmTaking 1.5 as a sensitivity coefficient;
the time delay of the zero sequence current II section protection is 0.3 s;
according to the requirements, the protection ranges of the phase distance I section protection and the grounding distance I section are 70% -80% of the line, the protection ranges of the phase distance II section protection, the grounding distance II section protection and the zero sequence current II section are all the line, the line extends into the high-voltage winding part of the lower-level line or the main transformer, and the time delay is 0.3 s.
Compared with the prior art, the invention has the beneficial effects that: the invention adopts the scheme of 110kV bus differential protection locking spare power automatic switching of the substation, can correctly act to lock the action of the spare power automatic switching and switch on the switch under various operation modes and when each 110kV bus has a fault, prevents the spare power automatic switching from being mistakenly switched on fault equipment, and is favorable for the safe and stable operation of a power grid. When the dead zone fault of the subsection (bus coupling), the 110kV bus differential protection can accurately act to remove the fault. The invention adopts the scheme of 110kV bus differential protection locking spare power automatic switching of the substation, can not mistakenly lock the spare power automatic switching action and switch on when the 110kV outgoing line fails in various operation modes, and improves the power supply reliability of a power grid. The invention adopts the scheme of 110kV bus differential protection locking spare power automatic switching of the substation, and the logic is simple and feasible. The scheme of the invention is applicable to: (1) only two power supply bus-differential branches have power supplies, and the outgoing branch and the transformer branch have no power supplies; (2) the two power supply bus difference branches are provided with power supplies, and the outgoing line branch and the transformer branch are also provided with power supplies.
Drawings
FIG. 1 is a schematic diagram of a 110kV bus differential protection lockout backup power automatic switching device;
FIG. 2 is a primary main wiring diagram of a single bus segment of a 110kV substation;
FIG. 3 is a 110kV double-bus (single-bus segment) primary main wiring diagram of a 220kV substation;
the symbols in fig. 1 are illustrated as follows:
Detailed Description
The invention is further described with reference to the following figures and specific examples.
As shown in fig. 1, a schematic diagram of a 110kV bus differential protection lockout backup power automatic switching device.
As shown in fig. 2, the power transmission and distribution network applied by the method of the present invention is a single bus segment primary main wiring system network of a substation. The primary main wiring of the 110kV system of the transmission and distribution network comprises: the No. 1 power supply bus differential spacing device and the No. 2 power supply bus differential spacing device are respectively connected with a 110kV I section bus and a 110kV II section bus; a segmented circuit breaker 3DL is arranged between the first segment bus and the second segment bus of 110kV, and is connected with a segmented current transformer (CT for short in the following); the No. 1 power supply bus differential interval equipment and the No. 2 power supply bus differential interval equipment are provided with bus differential circuit breakers 1DL and 2DL, and are connected with CT1 and CT2 in series; in addition, 110kV I section bus and II section bus are connected with 110kV bus voltage mutual inductors, the 110kV I section bus is also connected with No. 1 transformer branch, No. 2 transformer branch, No. 1110kV outgoing line branch, 110kV voltage mutual inductors (PT for short in the following) and 110kV bus lightning arresters; the 110kV II section bus is also connected with a No. 3 transformer branch, a No. 2110kV outgoing line branch, 110kV PT2 and 110kV bus lightning arresters.
The method of the invention can also be applied to 110kV double-bus (single-bus subsection) primary main wiring of the 220kV substation shown in FIG. 3.
For the 110kV single-bus subsection primary main connection, 110kV bus differential protection is configured, and how to realize a bus fault locking scheme of 110kV bus differential protection on 110kV backup power automatic switching is realized to meet the field operation requirement. Based on the method, the invention provides a 110kV bus differential protection blocking spare power automatic switching protection method for preventing the dead zone fault of the sectional breaker.
An example of the process of the invention is given below (taking fig. 2 as an example):
1. no. 1 power circuit breaker 1DL, No. 2 power circuit breaker 2DL operation, section circuit breaker 3DL hot standby
1.1110kV I section bus fault
Because power circuit breaker No. 1DL, power circuit breaker No. 2DL operate, section circuit breaker 3DL is hot standby, i.e., section circuit breaker 3DL trip position. When a 110kV I section bus has a fault, the protection of the upper-level No. 2 power line from the second section is started within the protection range of the upper-level power line from the second section, and the operation can be carried out after 0.3 s; meanwhile, when a 110kV I-section bus has a fault, the 110kV I-section bus does not contain a small differential relay of sectional current (the sectional current exits from a small differential element of the I-section bus by a bus differential at a tripping position), the 110kV bus differential large differential relay is started, the locking condition of the 110kV I-section bus composite voltage is opened, namely, the bus differential protection action jumps the circuit breaker on the I-section bus and locks the sectional circuit breaker 3DL to be switched on.
When the 110kV I section bus has a fault, the 110kV bus differential large differential relay is started, the 110kV I section bus composite voltage locking condition is opened, and the bus differential protection action locking subsection circuit breaker 3DL is switched on.
1.2110kV II-section bus fault
Because power circuit breaker No. 1DL, power circuit breaker No. 2DL operate, section circuit breaker 3DL is hot standby, i.e., section circuit breaker 3DL trip position. When the 110kV II-section bus has a fault, the protection is started at a distance of the upper-level power line from the II section, and the bus can act after 0.3 s; meanwhile, when the 110kV II-section bus has a fault, the 110kV II-section bus does not contain a small differential relay of the sectional current (the sectional current exits from a small differential element of the II-section bus by the bus difference at the opening position), the 110kV bus difference large differential relay is started, the locking condition of the 110kV II-section bus composite voltage is opened, namely, the bus difference protection action jumps the circuit breaker on the II-section bus and locks the sectional circuit breaker 3DL to be switched on simultaneously.
When the 110kV II-section bus has a fault, the 110kV bus differential large differential relay is started, the 110kV II-section bus composite voltage locking condition is opened, and the bus differential protection action locking sectional circuit breaker 3DL is switched on.
1.3110kV I-section bus upper outlet line fault
Because power circuit breaker No. 1DL, power circuit breaker No. 2DL operate, section circuit breaker 3DL is hot standby, i.e., section circuit breaker 3DL trip position. When the outgoing line (or transformer) on the 110kV I section bus has a fault, the corresponding protection starts tripping, and the 110kV bus differential protection large differential relay reflects an external fault and cannot be started, so that the 110 spare power automatic switching cannot be locked.
1.4110kV II-section bus outgoing line fault
Since power circuit breaker No. 1DL, power circuit breaker No. 2 operate 2DL, the sectionalizer 3DL is hot standby, i.e., the sectionalizing position of sectionalizer 3 DL. When the outgoing line (or transformer) on the 110kV II-section bus has a fault, the corresponding protection starts tripping, and the 110kV bus differential protection large differential relay reflects an external fault and cannot be started, so that the 110 spare power automatic switching cannot be locked.
1.5 Fault between sectionalizer and sectionalized CT
Because power circuit breaker No. 1DL, power circuit breaker No. 2DL operate, section circuit breaker 3DL is hot standby, i.e., section circuit breaker 3DL trip position. When a fault occurs between the sectional circuit breaker 3DL and the sectional CT, the sectional CT is positioned on the side of a 110kV I-section bus and is equivalent to a 110kV I-section bus fault, the bus differential protection is used for judging that the sectional circuit breaker 3DL is at the opening position, and the sectional current does not participate in the differential current calculation of a 110kV I-section bus or a 110kV II-section bus small differential element, so that the 110kV I-section bus does not contain a small differential relay of the sectional current, the 110kV bus differential large differential relay is started, the locking condition of the 110kV I-section bus composite voltage is opened, the circuit breaker on the 110kV I-section bus is tripped by the bus differential protection action of the 110kV I-section bus and the sectional circuit breaker is locked and closed at the same time, and.
When the 110kV I section bus has a fault, the 110kV bus differential large differential relay is started, the 110kV I section bus composite voltage locking condition is opened, and the bus differential protection action locking subsection circuit breaker 3DL is switched on.
2. No. 1 power circuit breaker 1DL, sectional circuit breaker 3DL operation, No. 2 power circuit breaker 2DL hot standby
2.1110kV I section bus fault
Because No. 1 power circuit breaker 1DL, section circuit breaker 3DL operation, No. 2 power circuit breaker 2DL is hot standby, No. 2 power circuit breaker 2DL separating brake position promptly. When a 110kV I section bus has a fault, the protection of the upper-level No. 1 power line from the second section is started within the protection range of the upper-level power line from the second section, and the operation can be carried out after 0.3 s; meanwhile, when a 110kV I section bus has a fault, the 110kV I section bus comprises a small differential relay of sectional current, a 110kV bus differential large differential relay is started, the 110kV I section bus composite voltage locking condition is opened, and bus differential protection actions are carried out to trip a circuit breaker on the 110kV I section bus and a 110kV sectional circuit breaker 3 DL; under the condition of the bus difference, a closing loop of the spare power automatic switching type 2 power circuit breaker is not closed, so that the spare power automatic switching still starts the 2DL of the type 2 power circuit breaker to be closed, and 110kV section II bus load is automatically switched to the inlet wire of the type 2 power supply to supply power.
2.2110kV II-section bus fault
Because No. 1 power circuit breaker 1DL, section circuit breaker 3DL operation, No. 2 power circuit breaker 2DL is hot standby, No. 2 power circuit breaker 2DL separating brake position promptly. When the 110kV II-section bus has a fault, the 110kV II-section bus comprises a small differential relay with sectional current, a 110kV bus differential large differential relay is started, the 110kV II-section bus composite voltage locking condition is opened, the 110kV II-section bus differential protection action jumps a circuit breaker on the 110kV II-section bus and a 110kV sectional circuit breaker, and the power supply of the 110kV I-section bus is ensured; due to the bus differential protection action of the 110kV II-section bus, a closing loop of the spare power automatic switching No. 2 power circuit breaker is closed, and therefore the spare power automatic switching cannot start the 2DL closing of the No. 2 power circuit breaker.
2.3110kV I-section bus upper outlet line fault
Because No. 1 power circuit breaker 1DL, section circuit breaker 3DL operation, No. 2 power circuit breaker 2DL is hot standby, No. 2 power circuit breaker 2DL separating brake position promptly. When the outgoing line (or transformer) on the 110kV I section bus has a fault, the corresponding protection starts tripping, and the 110kV bus differential protection large differential relay reflects that all the external faults can not be started, so that the 110 spare power automatic switching can not be locked.
2.4110kV II-section bus outgoing line fault
Because No. 1 power circuit breaker 1DL, section circuit breaker 3DL operation, No. 2 power circuit breaker hot standby, No. 2 power circuit breaker 2DL separating brake position promptly. When the outgoing line (or transformer) on the 110kV II-section bus has a fault, the corresponding protection starts tripping, and the 110kV bus differential protection large differential relay reflects that all the external faults cannot be started, so that the 110 spare power automatic switching cannot be locked.
2.5 Fault between sectionalizer 3DL and sectionalized CT
Because No. 1 power circuit breaker 1DL, section circuit breaker 3DL operation, No. 2 power circuit breaker 2DL is hot standby, No. 2 power circuit breaker 2DL separating brake position promptly. When a fault occurs between the sectional breaker 3DL and the sectional CT, the sectional CT is positioned on the side of a 110kV I section bus, which is equivalent to a 110kV II section bus fault, and the protection of the superior No. 1 power line is started within the protection range of the superior power line from the second section, and the action can be performed after 0.3 s; meanwhile, a 110kV II-section bus comprises a small differential relay with sectional current, a 110kV bus differential large differential relay is started, the 110kV II-section bus composite voltage locking condition is opened, and a bus differential protection action jumps a circuit breaker on the 110kV II-section bus and a 110kV section circuit breaker; due to the bus differential protection action of the 110kV II-section bus, a closing loop of the spare power automatic switching No. 2 power circuit breaker is closed, and therefore the spare power automatic switching cannot start the 2DL closing of the No. 2 power circuit breaker.
After the 110kV section breaker is tripped, the 110kV section I bus fault is changed, the 110kV section I bus does not contain a small differential relay of section current, the 110kV bus differential large differential relay is started, the 110kV section I bus composite voltage blocking condition is opened, the bus differential protection action trips the 110kV section I bus breaker, and the fault is removed.
Or after the 110kV II-section bus differential protection is started, on one hand, a T time open signal is output, on the other hand, a segmented circuit breaker 3DL is started to trip, after the segmented circuit breaker 3DL is tripped, the segmented circuit breaker 3DL is changed from a switch-on position to a switch-off position, a 110kV II-section bus contains a small differential relay of segmented current, a 110kV II-section bus composite voltage locking element is changed from action to return, the 110kV II-section bus does not contain the small differential relay of the segmented current and can not act, a 110kV bus differential large differential relay is still started, a segmented phase current element acts or a zero sequence current element acts, after the conditions of the 110kV I-section bus composite locking condition are opened, after the time delay T1, the bus differential protection acts to trip the circuit breaker on the 110kV I-section.
At this point, the total station loses power.
3. No. 2 power circuit breaker 2DL, sectional circuit breaker 3DL operation, No. 1 power circuit breaker 1DL hot standby
3.1110kV I section bus fault
Because No. 2 power circuit breaker 2DL, section circuit breaker 3DL operation, No. 1 power circuit breaker 1DL is hot standby, No. 1 power circuit breaker 1DL separating brake position promptly. When a 110kV I section bus has a fault, the protection of the upper-level No. 2 power line from the second section is started within the protection range of the upper-level power line from the second section, and the operation can be carried out after 0.3 s; meanwhile, when a 110kV I section bus has a fault, a 110kV I section bus comprises a small differential relay of sectional current, a 110kV bus differential large differential relay is started, the 110kV I section bus composite voltage locking condition is opened, a 110kV I section bus differential protection action jumps a circuit breaker on the 110kV I section bus and a 110kV section circuit breaker 3DL, and the power supply of a 110kV II section bus is ensured; after the 3DL of the 110kV section breaker is tripped, the closing of the 1DL of the No. 1 power supply breaker of the spare power automatic switching starting is locked due to the bus differential protection action of the 110kV I section bus.
3.2110kV II-section bus fault
Because No. 2 power circuit breaker 2DL, section circuit breaker 3DL operation, No. 1 power circuit breaker 1DL is hot standby, No. 1 power circuit breaker 1DL separating brake position promptly. When the 110kV II-section bus has a fault, the protection is started at a distance of the upper-level No. 2 power line from the II section, and the bus can act after 0.3 s; meanwhile, when a 110kV II-section bus has a fault, the 110kV II-section bus comprises a small differential relay with sectional current, a 110kV bus differential large differential relay is started, the 110kV II-section bus composite voltage locking condition is opened, bus differential protection acts, and the 110kV II-section bus differential protection acts to jump a circuit breaker on the 110kV II-section bus and a 110kV sectional circuit breaker 3 DL; because the busbar difference is not used for locking a closing loop of the spare power automatic switching 1 # power circuit breaker 1DL under the condition, the spare power automatic switching still starts the closing of the power circuit breaker 1DL, and the 110kV I section busbar is subjected to spare power automatic switching to the power inlet wire of the power supply 1 # for power supply.
3.3110kV I-section bus upper outlet line fault
Because No. 2 power circuit breaker 2DL, section circuit breaker 3DL operation, No. 1 power circuit breaker 1DL is hot standby, No. 1 power circuit breaker 1DL separating brake position promptly. When the outgoing line (or transformer) on the 110kV I section bus has a fault, the corresponding protection starts tripping, and the 110kV bus differential protection large differential relay reflects that all the external faults can not be started, so that the 110 spare power automatic switching can not be locked.
3.4110kV II-section bus outgoing line fault
Because No. 2 power circuit breaker 2DL, section circuit breaker 3DL operation, No. 1 power circuit breaker 1DL is hot standby, No. 1 power circuit breaker 1DL separating brake position promptly. When the outgoing line (or transformer) on the 110kV II-section bus has a fault, the corresponding protection starts tripping, and the 110kV bus differential protection large differential relay reflects that all the external faults cannot be started, so that the 110 spare power automatic switching cannot be locked.
3.5 Fault between sectionalizer and sectionalized CT
Because No. 2 power circuit breaker 2DL, section circuit breaker 3DL operation, No. 1 power circuit breaker 1DL is hot standby, No. 1 power circuit breaker 1DL separating brake position promptly. When a fault occurs between the sectional circuit breaker 3DL and the sectional CT, the sectional CT is positioned on the side of a 110kV I-section bus and is equivalent to a 110kV II-section bus fault, the 110kV II-section bus comprises a small differential relay of sectional current, a 110kV bus differential large differential relay is started, the 110kV II-section bus composite voltage locking condition is opened, and the bus differential protection action jumps a circuit breaker on the 110kV II-section bus and the 110kV sectional circuit breaker.
After the 110kV section breaker is tripped, the 110kV I section bus fault disappears, but the 110kV I section bus busbar differential protection cannot be operated, so that the closing of the spare power automatic switching No. 1 power supply breaker 1DL cannot be locked. The switch-on of a standby power automatic switching action starting No. 1 power circuit breaker 1DL is on a fault bus, and the distance between a superior No. 2 power circuit and a second section of protection is within the protection range of the distance between the superior power circuit and the second section, so that the circuit can only act after 0.3 s; meanwhile, when the 110kV I-section bus has a fault, the 110kV I-section bus does not contain a small differential relay of sectional current, the 110kV bus differential large differential relay is started, the 110kV I-section bus composite voltage locking condition is opened, the bus differential protection action jumps a circuit breaker on the I-section bus, and the fault is removed.
Or the spare power automatic switching operation starts the switch-on of the No. 1 power circuit breaker 1DL, when the switch-on is carried out on the I section bus of the fault, at the moment, the spare power automatic switching operation starts the switch-on of the No. 1 power circuit breaker 1DL, the 110kV I section bus composite voltage is locked and opened, the 110kV bus differential large differential relay operates again, the No. 1 power incoming line circuit breaker 1DL is changed from the switch-off position to the switch-on position, the No. 1 power incoming line phase current exceeds the setting value or the zero sequence current exceeds the setting value, and after the conditions are met, the bus differential protection operation trips the 110kV I section bus circuit breaker to remove the fault.
At this point, the total station loses power.
In addition to the above embodiments, the present invention may have other embodiments, and any technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of the claims of the present invention.
Claims (3)
1. A bus differential protection locking spare power automatic switching protection method for preventing dead zone faults of a sectional breaker is characterized by comprising the following steps:
1. the bus differential protection action is taken to jump I section bus circuit breaker and is blocked 1 power circuit breaker control of closing a floodgate simultaneously:
1.1 blocking Condition 1
(1) The 110kV I section bus composite voltage is locked and opened;
(2) a 110kV bus differential I section bus small differential relay containing sectional current acts;
(3) the 110kV bus differential large differential relay acts;
when the conditions are met, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
1.2 blocking Condition 2
(1) The 110kV I section bus composite voltage is locked and opened;
(2) a 110kV bus differential I section bus small differential relay without sectional current acts;
(3) the 110kV bus differential large differential relay acts;
(4) the sectional breaker is at the opening position;
when the conditions are met, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
1.3 blocking Condition 3
1.3.1 output T time open signal
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) a 110kV bus difference II-section bus small differential relay with sectional current acts;
(3) the 110kV bus differential large differential relay acts;
when the conditions (1) to (3) are all met, outputting a T time open signal;
1.3.2 latch-up conditions:
(1) when any condition of the conditions (1) to (3) of the 1.3.1 is not met, namely a 110kV bus differential II section bus small differential relay or a 110kV bus differential large differential relay or a 110kV II section bus composite voltage element is changed from the original action to return;
(2) there is an output T time open signal;
(3) when the section breaker is changed from the switching-on position to the switching-off position;
(4) the 110kV bus differential II-section bus small differential relay without sectional current does not act;
(5) the 110kV I section bus composite voltage is locked and opened;
(6) the 110kV bus differential large differential relay acts;
(7) the phase current element of the segmented CT exceeds a setting value, or the zero-sequence current element exceeds the setting value;
when the conditions are all met, after delay time t1, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
1.3 blocking Condition 4
(1) The 110kV I section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) the spare power automatic switching starts a No. 1 power incoming line breaker 1DL to switch on;
(4) the No. 1 power incoming line breaker 1DL is changed from an opening position to a closing position;
(5) the phase current element of the inlet wire of the No. 1 power supply exceeds a setting value, or the zero-sequence current element exceeds the setting value;
when the conditions are all met, the bus differential protection action tripping I section bus circuit breaker simultaneously locks the No. 1 power circuit breaker to be switched on;
2. the control that the bus differential protection action jumps II sections of bus circuit breakers and locks No. 2 power circuit breakers to switch on simultaneously is as follows:
2.1 blocking Condition 1
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) a 110kV bus difference II-section bus small differential relay with sectional current acts;
(3) the 110kV bus differential large differential relay acts;
when the conditions are met, the bus differential protection action tripping II-section bus circuit breaker simultaneously locks the No. 2 power circuit breaker to be switched on;
2.2 blocking Condition 2
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) a 110kV bus differential II-section bus small differential relay without sectional current acts;
(3) the 110kV bus differential large differential relay acts;
(4) the sectional breaker is at the opening position;
when the conditions are met, the bus differential protection action tripping II-section bus circuit breaker simultaneously locks the No. 2 power circuit breaker to be switched on;
2.3 blocking Condition 3
(1) The 110kV II-section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) the spare power automatic switching starts a No. 2 power incoming line breaker 2DL to switch on;
(4) the No. 2 power incoming line breaker 2DL is changed from an opening position to a closing position;
(5) the phase current element of the inlet wire of the No. 2 power supply exceeds a setting value, or the zero-sequence current element exceeds the setting value;
when the conditions are all met, the bus differential protection action tripping II-section bus circuit breaker simultaneously locks the No. 2 power circuit breaker to be switched on;
3. the control of the closing of the bus differential protection action locking section breaker is as follows:
3.1 blocking Condition 1:
(1) the 110kV I section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) a 110kV bus differential I section bus small differential relay containing sectional current acts;
when the conditions are met, the bus differential protection action tripping sectional circuit breaker locks the sectional circuit breaker to be switched on at the same time;
3.2 blocking Condition 2:
(1) the 110kV II-section bus composite voltage is locked and opened;
(2) the 110kV bus differential large differential relay acts;
(3) a 110kV bus difference II-section bus small differential relay with sectional current acts;
when the conditions are met, the bus differential protection action tripping sectional circuit breaker locks the sectional circuit breaker to be switched on at the same time;
3.3 blocking Condition 3:
(1) the 110kV bus differential large differential relay acts;
(2) the composite voltage of the 110kV I section bus is locked and unlocked or the composite voltage of the 110kV II section bus is locked and unlocked;
and when the conditions are met, the bus differential protection action tripping sectional breaker locks the sectional breaker to be switched on at the same time.
2. The busbar differential protection latching backup power automatic switching protection method for preventing the dead zone fault of the sectionalizing breaker as claimed in claim 1, wherein the T time in the output T time open signal is 200 and 300 milliseconds; the delay time t1 takes 20-40 milliseconds.
3. The bus differential protection locking backup power automatic switching protection method for preventing the dead zone fault of the sectionalizing circuit breaker according to claim 1, wherein the setting and requirements of the related protection in the locking conditions 1 and 2 are as follows:
1. in the locking conditions 1 and 2, the phase current element fixed value of the subsection or the inlet wire of the No. 1 power supply or the inlet wire of the No. 2 power supply is set according to the maximum short-circuit current which flows through the protection when the middle and low-voltage buses of the transformer substation on the local substation or the 110kV outlet line are short-circuited:
(1) in the formula (I), the compound is shown in the specification,
the maximum short-circuit current K of the protection flows when the middle and low-voltage buses of the maximum transformer of the substation or the substation on a 110kV outgoing line are short-circuited in the maximum operation mode of the systemkTaking 1.3-1.5 as a reliable coefficient;
the zero sequence current element fixed value of the section or No. 1 power supply inlet wire has sensitivity setting more than or equal to 1.5 times according to the minimum operation mode of the system for 110kV bus single-phase earth fault:
(2) in the formula (I), the compound is shown in the specification,
is 110kV bus single-phase short-circuit current in the minimum operation mode of the system, KlmTaking 1.5 as a sensitivity coefficient;
2. phase current elements of a segmented or No. 1 power supply inlet wire or No. 2 power supply inlet wire adopt phase currents of an A phase, a B phase and a C phase;
the phase current element and the zero sequence current element of No. 3.1 power supply incoming line or No. 2 power supply incoming line are required to be provided with a direction element, and the direction element points to: pointing from the line to the bus bar.
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