CN103001195B - The relay protecting method of failure in transformer dead zone and the circuit breaker tripping of fault side - Google Patents

Abstract

The invention relates to a relay protection control method for quickly removing a dead zone fault of a transformer in a 220kV substation and refusing to operate a circuit breaker on the fault side of the transformer. In this method, the following conditions are set in the tripping control of the dead zone fault on one side of the transformer: Condition 1, the backup protection trip outlet relay on this side of the transformer is in the action state or the trip outlet relay of other electrical quantity protection is in the action state; Condition 2, the transformer The current of phase A, phase B or phase C on the side reaches the set value, or the zero-sequence current or negative-sequence current ≥ the set value; when all the above conditions are met, the differential protection TA of the transformer on this side of the transformer will be exited after a delay of a set value. The transformer differential protection action trips the circuit breaker on the other side of the transformer to remove the fault; when any of the above conditions is not met, immediately connect to the transformer differential TA on this side of the transformer. The invention has simple action principle, high reliability, and can quickly cut off faults in dead zones of various voltage levels on each side of the transformer.

Description

Relay Protection Method for Transformer Dead Zone Fault and Breaker Rejection on Fault Side

technical field

The invention belongs to the control technology of electric power transmission and distribution network, and relates to a relay protection control method for quickly removing transformer dead-zone faults and refusing to operate a circuit breaker at the transformer fault side in a 220kV substation.

Background technique

GB/T14285-2006 "Technical Regulations for Relay Protection and Safety Automatic Devices" stipulates that the transformer should be equipped with longitudinal differential protection as the main protection and electrical protection such as backup protection for transformer overcurrent caused by external phase-to-phase short circuit and grounding short circuit, Among them, the backup protection for responding to phase-to-phase short circuit includes composite voltage overcurrent protection and phase-to-phase impedance protection, and the backup protection for responding to grounding short circuit includes zero-sequence current protection and grounding impedance protection. These backup protections are equipped with different backup protections according to the voltage levels of transformers of different voltage levels and the voltage levels of each side, and generally all sides of the transformer are equipped with backup protections that respond to external phase-to-phase short-circuits and grounding short-circuits. The protection configuration of 220kV and above transformers is specified in Q/GDW_175-2008_ "Standardized Design Specifications for Transformers, High Voltage Shunt Reactors, Busbar Protection and Auxiliary Devices"; Short-circuit composite voltage overcurrent protection (if the 110kV neutral point is generally not grounded, the zero-sequence current protection is generally not used, and only the 110kV neutral point gap protection is used; if the 110kV neutral point is generally grounded, it is configured with Zero-sequence current protection is used, and 110kV neutral point gap protection is disabled).

The so-called transformer dead-zone fault refers to the short-circuit fault that occurs between the circuit breaker on one side of the transformer and the current transformer (hereinafter referred to as TA) used for the differential protection of the transformer on this side (see Figure 2). Since the fault is outside the protection range of the transformer longitudinal differential protection, although the backup protection or other protection (such as busbar protection) on the fault side operates to trip the circuit breaker on the side of the transformer, the fault still exists. The protection action or the backup protection action of this side is used to trip the transformer general outlet relay circuit and trip the transformer power side circuit breaker to finally remove the fault. In this case, the time to remove the fault is generally longer; if the transformer is a high-impedance transformer, the backup protection Maybe because the short-circuit current does not reach the start-up value, the fault cannot be removed. Only when the transformer is burned to the point that the short-circuit current reaches and exceeds the protection start-up value can the backup protection on the power supply side of the transformer be activated to remove the fault. Although the invention patent ZL200810201305.3 "Relay Protection Method for Eliminating Transformer Dead-zone Faults" proposes a scheme to trip the circuit breakers on the other side of the transformer after judging the dead-zone faults, the time to remove the faults is still a little long, and it is only suitable for 110kV transformers. The present invention will propose another logic circuit to complete the transformer protection device of various voltage levels for the substations of the applied power transmission and distribution network and quickly cut off the relay protection technology of dead zone faults of various voltage levels on each side of the transformer Program.

Contents of the invention

The problem to be solved by the present invention is to provide a transformer protection device that can be applied to power transmission and distribution networks for substations with various voltage levels. And the relay protection method that the transformer circuit breaker refuses to operate.

Provide the technical scheme of the inventive method below.

The substation of the power transmission and distribution network applied in the method of the present invention is a protective device for two-winding transformers, three-winding transformers, autotransformers or other transformers of various voltage levels; in theory, the transformer has several operating voltages The level is connected to the external circuit equipment through the circuit breaker interval equipment (composed of isolation switches, circuit breakers, current transformers, etc.), there are several transformer dead zone fault locations, that is, there are two operating voltage levels through the circuit breaker interval equipment and If the external circuit equipment is connected, there will be at least 2 transformer dead-zone fault locations; if there are 3 operating voltage levels connected to the external circuit equipment through the circuit breaker spacer, there will be at least 3 transformer dead-zone fault locations (1 operating voltage level if If there are 2 circuit breaker interval devices, then the operating voltage level side is 2 transformer dead zone fault positions).

For the convenience of description, the transformer dead-zone fault occurs in the circuit breaker interval equipment of one of the operating voltage levels of the transformer, and the method of quickly starting to remove the fault is described. The transformers of other voltage levels and the transformers are two-winding transformers, three-winding transformers, automatic Coupling transformer or other transformers, or the combination of other voltage levels on each side of the transformer, the method is similar and will not be repeated here. The circuit breaker bay equipment is composed of isolating switch, circuit breaker, TA and other equipment. TA has several sets of secondary windings respectively. These sets of secondary windings are respectively connected to the transformer differential protection (backup protection) from the bus side to the transformer side Secondary equipment such as busbar differential protection, measurement and metering. A bushing TA is also installed at the bushing of the transformer. The TA used for the backup protection on each side of the transformer of 110kV and below is separate from the differential protection of the transformer. different secondary windings. Its control method includes the following control process:

In the trip control of the dead zone fault on one side of the transformer and the refusal of the transformer circuit breaker to operate, the following conditions are set:

Condition 1: The backup protection trip outlet relay on this side of the transformer is in action or the trip outlet relay of other electrical protection (such as bus differential protection on this side) is in action;

Condition 2: The A-phase or B-phase or C-phase current on this side of the transformer reaches the set value, or the zero-sequence current or negative-sequence current ≥ the set value;

When all the above conditions are met, delay a certain value of t1 (such as 150ms) and then exit the transformer differential protection TA on this side of the transformer, that is, the current on this side of the transformer does not participate in the calculation of the transformer differential protection current; when any of the above conditions is not satisfied , immediately connect to the transformer differential TA on this side of the transformer, that is, the current on this side of the transformer participates in the calculation of the transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the fault When the fault outside the zone becomes the fault inside the zone, the differential protection of the transformer will activate the differential outlet relay of the transformer and trip the other circuit breakers of the transformer, thus eliminating the fault.

Compared with the existing method for removing dead zone faults of transformers, the present invention has the following advantages:

1. It is suitable for the technical scheme of transformer protection devices such as two-winding transformers, three-winding transformers, and autotransformers of various voltage levels for substations in power transmission and distribution networks.

2. After judging the dead zone fault, the method adopts a delay to exit the transformer differential TA on the transformer fault side, that is, the current on the transformer fault side does not participate in the calculation of the transformer differential protection current. The criterion is simple and practical; after judging the dead zone fault, only The transformer differential protection is quickly started after a short time delay (such as 150ms), and the purpose of quickly removing the dead zone fault is achieved;

3. Since the breaker opening position contact is not included in the criterion, for a bus fault on a certain side of the substation, the bus protection action or the backup protection action on the transformer fault side, but the circuit breaker on the transformer fault side refuses to operate (circuit breaker failure), this The inventive scheme can also exit the transformer differential TA on the fault side of the transformer after a certain time limit (such as 150 ms) after judging that the circuit breaker refuses to operate, start the transformer differential protection, and quickly remove the fault.

Description of drawings

Fig. 1 is a logic diagram of the transformer differential TA on a certain side of the transformer in the method embodiment of the present invention, starting and exiting the dead zone fault of the side;

Figure 2 is a part of the primary main wiring diagram of the existing 220kV substation.

The symbols in Figure 1 are explained as follows:

- Indicates a logical AND relationship, that is, when all input conditions are met, the output is valid;

- Indicates a logical or relationship, that is, when any of the input conditions is satisfied, the output is valid;

- Indicates that when all the conditions are met, the output is valid after a delay of t1; when any of the conditions is not met, it returns immediately.

detailed description

Taking the protection of a 220kV autotransformer in a 220kV substation as an example, to describe the method of quickly starting and removing the fault in the dead zone of the transformer, the transformers of other voltage levels, and the transformers are two-winding transformers, three-winding For other transformers, or combinations of other voltage levels on each side of the transformer, the methods are similar and will not be repeated here. As shown in Figure 2, it is part of the primary main wiring diagram of a 220kV substation, a 220kV autotransformer, and the transformer is equipped with a high-voltage side circuit breaker 1QF, a medium-voltage side circuit breaker 2QF, and a low-voltage side circuit breaker 3QF; the high-voltage side circuit breaker A set of independent TAs are respectively installed at 1QF of the transformer, 2QF of the medium-voltage side circuit breaker, and 3QF of the low-voltage side circuit breaker. The TAs have several sets of secondary windings respectively. A casing TA is set. The TA configuration on each side of the 220kV transformer is shown in Figure 2, in which the secondary winding of the TA at the circuit breaker on the high voltage side of the transformer (220kV) is respectively connected from the busbar side to the transformer side with the first set of transformer longitudinal differential and backup protection, and the second set of Transformer longitudinal differential and backup protection (220kV transformer protection generally adopts the integrated configuration of main protection and backup protection, that is, each side of the main protection and backup protection shares the same set of TA secondary windings and voltage transformer secondary windings, and the main protection and backup protection All hardware devices and software for backup protection are in the same chassis), the first set of 220kV bus differential protection, the second set of 220kV bus differential protection (according to Q/GDW_175-2008_ "Transformers, high-voltage parallel The transformer protection designed in "Standardized Design Specifications for Devices" does not have a special circuit breaker failure current circuit, which is realized by bus differential protection; otherwise, a special circuit breaker failure current circuit), metering, and measurement are set; The TA secondary winding at the transformer is respectively connected with the first set of transformer longitudinal differential and backup protection, the second set of transformer longitudinal differential and backup protection, 110kV bus differential protection, metering and measurement from the bus side to the transformer side; The TA secondary winding at the circuit breaker on the low-voltage side (35kV or 10kV, etc.) is respectively connected from the busbar side to the transformer side with the first set of transformer longitudinal differential and backup protection, the second set of transformer longitudinal differential and backup protection (busbar protection ), fault recording, measurement, measurement, etc.

To determine whether there is current in phase A, phase B or phase C of the transformer side, the differential protection TA current on this side of the transformer can be collected, and the current setting can be set to (0.5-1) times the rated current of the high voltage side of the transformer; when the side of the transformer When it is an effective grounding system, the zero-sequence current or negative-sequence current setting can be set to 120A-180A.

When the voltage level on one side of the transformer is 35kV and below, the system is generally an ungrounded system or a grounded system through an arc suppression coil, and the zero-sequence current criterion on this side of the transformer may not be used. If it is a resistance-grounded system, the zero-sequence current criterion on this side of the transformer can be used.

Provide below the embodiment that the inventive method is applied to transformer dead zone fault and removes this fault fast:

1. Quick removal method of transformer high voltage side dead zone fault

(1) When a phase-to-phase short circuit or ground fault occurs between the transformer high-voltage side circuit breaker lQF and the high-voltage side TA used for transformer differential protection (that is, the TA at the high-voltage side circuit breaker), the fault is within the scope of the transformer’s longitudinal differential protection outside, but within the protection range of the first set of 220kV bus differential protection and the second set of 220kV bus differential protection, the first set of 220kV bus differential protection and the second set of 220kV bus differential protection start to trip all the faulty buses Switch (including transformer high voltage side circuit breaker lQF). If there is power supply on the other side of the transformer, although the circuit breaker 1QF has tripped, the fault has not been cut off, and the fault phase still has current or zero-sequence current or negative-sequence current exceeding the set value, so the first set of 220kV bus differential protection, the second set The 220kV bus differential protection still operates and does not return (or the backup protection on the high voltage side of the transformer is delayed until the backup protection still operates and does not return), so the two conditions for judging the dead zone fault are met, and after a certain time delay (such as 150ms), Exit the transformer differential TA on the high-voltage side of the transformer, that is, the current on the high-voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the dead zone When the fault changes from an external fault to an internal fault, the transformer differential protection will activate the transformer differential outlet relay and trip the other circuit breakers of the transformer to remove the fault.

(2) When the high-voltage side circuit breaker lQF of the transformer has already occurred the dead zone fault on the high-voltage side of the transformer at the opening position, the fault is outside the scope of the transformer longitudinal differential protection, but the first set of 220kV bus differential protection, the second set Within the protection range of 220kV bus differential protection, the first set of 220kV bus differential protection and the second set of 220kV bus differential protection start to trip all switches of the faulty bus. If there is power supply on the other side of the transformer, although the circuit breaker 1QF is already in the opening position, but the fault phase has short-circuit current or zero-sequence current or negative-sequence current exceeding the set value, the first set of 220kV bus differential protection, the second set of 220kV bus differential protection The delay time for the active protection action or the backup protection start-up on the high-voltage side of the transformer is up, so the two conditions for judging the dead-zone fault are met. The current does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the dead zone When the fault changes from an external fault to an internal fault, the transformer differential protection will activate the transformer differential outlet relay and trip the other circuit breakers of the transformer to remove the fault.

(3) If it is a 220kV bus fault, although the two sets of 220kV bus differential protections operate, the two sets of 220kV bus differential protections start to trip all other switches of the faulty bus, but the transformer high-voltage side circuit breaker lQF refuses to operate. If there is power supply, the fault is not cut off, and the fault phase still has current or the zero-sequence current or negative-sequence current exceeds the set value, so the first set of 220kV bus differential protection and the second set of 220kV bus differential protection still operate and do not return (or the transformer The backup protection on the high-voltage side starts to be delayed until the backup protection still does not return), so the two conditions for judging the dead-zone fault are met, and after a certain time limit (such as 150ms), exit the transformer differential TA on the high-voltage side of the transformer, that is, the transformer high-voltage Side current does not participate in the calculation of transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the dead zone When the fault changes from an external fault to an internal fault, the transformer differential protection will activate the transformer differential outlet relay and trip the other circuit breakers of the transformer to remove the fault.

(4) If there is no power supply on the other side of the transformer in the substation, there will be no fault current flowing on the fault side of the transformer. Therefore, if the two conditions for judging the dead zone fault are not satisfied, the transformer differential TA on the high voltage side of the transformer will not be activated and exited.

2. Quick removal method for dead zone faults on the medium voltage side of transformers

(1) When a phase-to-phase short circuit or ground fault occurs between the transformer medium-voltage side circuit breaker 2QF and the medium-voltage side TA used for transformer differential protection (that is, the TA at the medium-voltage side circuit breaker), the fault occurs in the transformer longitudinal differential Outside the protection range, but within the protection range of the 110kV bus differential protection, the 110kV bus differential protection starts to trip all the switches of the faulty bus (including the circuit breaker 2QF on the medium voltage side of the transformer), although the circuit breaker 2QF has tripped, But the fault is not removed, the fault phase still has current or the zero-sequence current or negative-sequence current exceeds the set value, so the 110kV bus differential protection still operates and does not return (or the backup protection on the high-voltage side of the transformer is delayed until the backup protection still operates and does not return ), then the two conditions for judging the dead zone fault are met, and after a certain time delay (such as 150ms), the transformer differential TA on the medium-voltage side of the transformer is exited, that is, the current on the medium-voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the dead zone When the fault changes from an external fault to an internal fault, the transformer differential protection will activate the transformer differential outlet relay and trip the other circuit breakers of the transformer to remove the fault.

(2) When the transformer medium voltage side circuit breaker 2QF has occurred in the open position of the transformer medium voltage side dead zone fault, the fault is outside the transformer longitudinal differential protection range, but within the 110kV bus differential protection protection range, The 110kV bus differential protection starts to trip all the switches of the faulty bus. Although the circuit breaker 2QF is in the opening position, but the fault phase has a short-circuit current or zero-sequence current or negative-sequence current exceeding the set value, the 110kV bus differential protection operates or the delay time for the backup protection on the high voltage side of the transformer is activated, so it is judged dead The two conditions of zone fault are met, and after a certain time delay (such as 150ms), the transformer differential TA on the medium-voltage side of the transformer is exited, that is, the current on the medium-voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the dead zone When the fault changes from an external fault to an internal fault, the transformer differential protection will activate the transformer differential outlet relay and trip the other circuit breakers of the transformer to remove the fault.

(3) If it is a 110kV bus fault, although the 110kV bus differential protection operates, the 110kV bus differential protection starts to trip all other switches of the faulty bus, but the medium-voltage side circuit breaker 2QF of the transformer refuses to operate, but the fault has not been removed, and the fault phase There is still current or the zero-sequence current or negative-sequence current exceeds the set value, so the 110kV bus differential protection still operates and does not return (or the backup protection on the medium voltage side of the transformer still does not return after the start-up delay time expires), so the dead zone is judged When the two conditions of the fault are met, after a certain time delay (such as 150ms), the transformer differential TA on the medium voltage side of the transformer is exited, that is, the current on the medium voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection removes the current on the fault side from the calculation of the transformer differential protection current, it is equivalent to changing the comprehensive differential current of the transformer differential protection from 0 or very small to the short-circuit current of the short-circuit point, which makes the transformer differential protection judge the dead zone When the fault changes from an external fault to an internal fault, the transformer differential protection will activate the transformer differential outlet relay and trip the other circuit breakers of the transformer to remove the fault.

3. Quick removal method for dead zone faults on the low voltage side of transformers

(1) The voltage level of the low-voltage side of the transformer is generally 35kV and below. The system is generally an ungrounded system or a grounded system through an arc suppression coil or a grounded system through a resistance. When a phase-to-phase short circuit or ground fault occurs between the transformer low-voltage side circuit breaker 3QF and the low-voltage side TA used for transformer differential protection (ie, TA at the low-voltage side circuit breaker) Outside the protection range of the low-voltage bus, but within the protection range of the low-voltage bus differential protection, the low-voltage bus differential protection starts to trip all the switches of the faulty bus (including the transformer low-voltage side circuit breaker 3QF), although the circuit breaker 3QF has tripped, But the fault is not cut off, the fault phase still has current or the negative sequence current or zero sequence current exceeds the set value (when the system is grounded by resistance), so the differential protection of the low-voltage busbar still operates and does not return (or the backup protection of the low-voltage side of the transformer (when there is no busbar) During protection, one of the low-voltage side backup protections is used as the busbar protection) to start the delay time and the backup protection still does not return), so the two conditions for judging the dead zone fault are met, and after a certain time limit (such as 150ms) , exit the transformer differential TA on the low-voltage side of the transformer, that is, the current on the low-voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection withdraws the fault side current from the current calculation of the transformer differential protection, the fault in the dead zone is changed from a fault outside the differential protection zone of the transformer to a fault inside the zone, and the transformer differential protection activates the transformer differential outlet relay and trips. Transformer and other circuit breakers cut off the fault.

(2) When the 3QF low-voltage side circuit breaker of the transformer has occurred the above-mentioned low-voltage side dead zone fault at the opening position, the fault is outside the transformer longitudinal differential protection range, but within the protection range of the low-voltage bus differential protection. The bus differential protection starts to trip all the switches of the faulty bus. Although the circuit breaker 3QF is in the opening position, there is still current in the fault phase or the negative sequence current or zero sequence current exceeds the set value (when passing through the resistance grounding system). Bus differential protection action or transformer low-voltage side backup protection (when there is no busbar protection, one set of low-voltage side backup protection is used as busbar protection) starts delay time action, so the two conditions for judging the dead zone fault are met, delay After a certain time limit (such as 150ms), exit the transformer differential TA on the low-voltage side of the transformer, that is, the current on the low-voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection withdraws the fault side current from the current calculation of the transformer differential protection, the fault in the dead zone is changed from a fault outside the differential protection zone of the transformer to a fault inside the zone, and the transformer differential protection activates the transformer differential outlet relay and trips. Transformer and other circuit breakers cut off the fault.

(3) If it is a low-voltage bus fault, although the low-voltage bus differential protection operates, the low-voltage bus differential protection starts to trip all other switches of the faulty bus, but the transformer low-voltage side circuit breaker 3QF refuses to operate, so the fault is not cut off, and the fault phase remains If there is current or the negative sequence current exceeds the set value, but the low-voltage bus differential protection still operates and does not return (or the backup protection on the low-voltage side of the transformer still operates after the start-up delay time reaches the backup protection), then the two conditions for judging the dead zone fault are met, After a certain time delay (such as 150ms), exit the transformer differential TA on the low-voltage side of the transformer, that is, the current on the low-voltage side of the transformer does not participate in the calculation of the transformer differential protection current. Since the transformer differential protection withdraws the fault side current from the current calculation of the transformer differential protection, the fault in the dead zone is changed from a fault outside the differential protection zone of the transformer to a fault inside the zone, and the transformer differential protection activates the transformer differential outlet relay and trips. Transformer and other circuit breakers cut off the fault.

4. Quick removal method for other transformer dead zone faults

When the voltage level on one side of the transformer is 35kV or below, the system is generally an ungrounded system or a grounded system through an arc suppressing coil or a grounded system through a resistance. The quick removal method of the dead zone fault on this side of the transformer can refer to the dead zone on the low voltage side of the 220kV transformer. Area fault quick removal method. When the voltage level on one side of the transformer is 220kV and above, the system is generally an effective grounding system, and the quick removal method of the dead zone fault on this side of the transformer can refer to the quick removal method of the dead zone fault on the high voltage side of the 220kV transformer.

When the transformer is a two-winding transformer, it is equivalent to the lack of one side of the above-mentioned three-winding transformer, and it is only necessary to consider the method of quick removal of dead zone faults on both sides of the transformer. When the voltage level on one side of the transformer has two branches, it is enough to consider the two dead zone fault quick removal methods respectively.

Claims (5)

1. A relay protection method for transformer dead zone fault and fault side circuit breaker refusal to move, characterized in that the method comprises the following control steps: Step 1, start-up mode, that is, in the trip control of the dead zone fault on one side of the transformer and the refusal of the transformer circuit breaker to operate, set the following conditions Condition 1, the backup protection trip outlet relay on the side of the transformer is in action or the trip outlet relay of other electrical quantity protection is in action; Condition 2: The A-phase or B-phase or C-phase current on this side of the transformer reaches the set value, or the zero-sequence current or negative-sequence current ≥ the set value; Step 2, tripping mode, that is, when all the conditions of the above starting mode are met, the transformer fault side transformer differential protection TA is exited after a delay of t1, that is, the transformer fault side current does not participate in the transformer differential protection current calculation; The differential protection removes the current on the fault side from the calculation of the differential protection current of the transformer, which is equivalent to changing the comprehensive differential current of the differential protection of the transformer from zero or very small to the short-circuit current of the short-circuit point, which makes the differential protection of the transformer judge that the fault is caused by the area When the external fault becomes an internal fault, the differential protection of the transformer will activate the differential outlet relay of the transformer, trip the circuit breaker on the other side of the transformer, and remove the fault; when any condition of the above starting mode is not met, immediately connect the transformer The fault side transformer differential TA, that is, the fault side current of the transformer participates in the calculation of the transformer differential protection current. 2. The relay protection method for transformer dead-zone faults and failure-side circuit breaker refusal according to claim 1, characterized in that: the method includes transformer dead-zone faults such as two-winding transformers, three-winding transformers, and autotransformers Technical solutions for protection and transformer circuit breaker rejection action protection, as well as the relay protection control method for rapid removal of transformer dead zone faults on the high voltage side of transformers at 220kV voltage level substations and relay protection control method for transformer high voltage side circuit breaker rejection action, and rapid removal of transformers at the medium voltage side A relay protection control method for dead zone faults and transformer medium-voltage side circuit breaker refusal to operate, and a relay protection control method for quickly removing transformer dead zone faults on the low-voltage side and transformer low-voltage side circuit breaker refusal to operate. 3. The relay protection method for transformer dead-zone fault and failure-side circuit breaker refusal to operate according to claim 1, characterized in that: the delay time t1 in step 2 is fixed at 150ms. 4. The relay protection method for transformer dead-zone faults and failure-side circuit breaker refusal to operate according to claim 1, characterized in that: judge the A-phase current and B-phase current on the high-voltage side of the transformer or the medium-voltage side of the transformer or the low-voltage side of the transformer The collection of current and C-phase current is to collect the differential protection TA current on this side of the transformer, and the current setting value is set to (0.5-1) times the rated current on this side of the transformer; When the side is an effective grounding system, the zero-sequence current setting is set to 120A-180A. 5. The relay protection method for transformer dead-zone fault and failure-side circuit breaker refusal according to claim 1, characterized in that: the grid short-circuit fault targeted by the method is one of the following: 1) The dead zone fault on the high voltage side of the transformer or the dead zone fault on the medium voltage side or the dead zone fault on the low voltage side of the transformer that occurs during normal operation of the substation; 2) The transformer operates normally, but the high-voltage side dead zone fault occurs when the high-voltage side circuit breaker is disconnected, or the medium-voltage side dead zone fault occurs when the medium-voltage side circuit breaker is disconnected, or the low-voltage side fault occurs when the low-voltage side circuit breaker is disconnected. dead zone failure; 3) When the substation is in normal operation, the high-voltage side bus is short-circuited, and the bus differential protection action on the high-voltage side trips the high-voltage side circuit breaker of the transformer, but the transformer high-voltage side circuit breaker refuses to operate; or when the substation is in normal operation, the medium-voltage side bus is short-circuited, The medium-voltage side bus differential protection action trips the medium-voltage side circuit breaker of the transformer, but the transformer medium-voltage side circuit breaker refuses to operate; or when the substation is in normal operation, the low-voltage side bus is short-circuited, and the low-voltage side bus protection or the transformer low-voltage side backup protection trips. The transformer low-voltage side circuit breaker, but the transformer low-voltage side circuit breaker refused to operate.