阅读说明：本技术 一种三相联动式断路器的非全相保护逻辑实现方法 (Non-full-phase protection logic implementation method of three-phase linkage type circuit breaker ) 是由 周尧 黄小冬 何泽胜 曹建军 李有春 马静 詹水秋 朱恩飞 焦维亮 张乾 于 2021-08-18 设计创作，主要内容包括：本发明涉及继电保护技术领域,一种三相联动式断路器的非全相保护逻辑实现方法,包括以下步骤：步骤S1：保护装置根据GCB位置接点变动判断是否启动非全相保护以及发电机组的供能方式；步骤S2：在发电机组并网或者解列时,分别采用并网判据和解列判据判断是否满足保护动作条件；步骤S3：当中任一判据满足保护动作条件时,保护动作于停机或者报警。本发明设计了一种采用多方式、多判据的非全相保护逻辑,能够满足发电厂现场的实际情况,解决了现有的GCB非全相保护单纯以负序电流或零序电压等作为单一判据的问题。(The invention relates to the technical field of relay protection, in particular to a non-full-phase protection logic implementation method of a three-phase linkage type circuit breaker, which comprises the following steps: step S1: the protection device judges whether to start non-full-phase protection and an energy supply mode of the generator set according to the change of the GCB position contact; step S2: when the generator set is connected to the grid or disconnected from the grid, whether the protection action condition is met or not is judged by respectively adopting a grid connection criterion and a disconnection criterion; step S3: when any criterion meets the protection action condition, the protection action is stopped or an alarm is given. The invention designs a multi-mode and multi-criterion non-full-phase protection logic, which can meet the actual situation of a power plant site and solve the problem that the conventional GCB non-full-phase protection only uses negative-sequence current or zero-sequence voltage and the like as a single criterion.)

1. A non-full-phase protection logic realization method of a three-phase linkage type circuit breaker is characterized by comprising the following steps:

step S1: the protection device judges whether to start non-full-phase protection and an energy supply mode of the generator set according to the change of the GCB position contact, wherein the energy supply mode comprises grid connection and disconnection, and the step S2 is executed;

step S2: when the generator set is connected to the grid or disconnected from the grid, respectively adopting a grid connection criterion and a disconnection criterion to judge whether the protection action condition is met, and executing the step S3;

step S3: when any criterion meets the protection action condition, the protection action is stopped or an alarm is given.

2. The method for implementing the non-full-phase protection logic of the three-phase linkage type circuit breaker according to claim 1, wherein in the step S1, the GCB position contact change is specifically: when the GCB position contact changes into GCB closing or GCB opening, non-full-phase protection is started, when GCB closing is detected, a generator set is connected to the grid, non-full-phase protection is started and the protection time is widened, and when GCB opening is detected, the generator set is disconnected, non-full-phase protection is started and the protection time is widened.

3. The method as claimed in claim 2, wherein the protection time is 300 s.

4. The method as claimed in claim 2, wherein in step S2, if the generator set is connected to the grid, it is determined whether the protection operation condition is satisfied according to the grid connection criterion, and if the generator set is disconnected, it is determined whether the protection operation condition is satisfied according to the disconnection criterion.

5. The method for realizing the non-full-phase protection logic of the three-phase linkage type circuit breaker according to claim 4, wherein the grid connection criterion is specifically as follows: the protection device collects a real-time value of a first analog quantity related to grid-connected protection, judges whether the real-time value of the first analog quantity is larger than a fixed value of a second analog quantity within the broadening time, and judges that a protection action condition is met after time delay if the real-time value of the first analog quantity is larger than the fixed value.

6. The method for implementing the non-full-phase protection logic of the three-phase linkage type circuit breaker according to claim 5, wherein the first analog quantity comprises a zero-sequence voltage component difference on two sides of the GCB, a minimum zero-sequence voltage on two sides of the GCB, and a minimum negative-sequence current on two sides of the GCB.

7. The method for implementing the non-full-phase protection logic of the three-phase linkage type circuit breaker according to claim 6, wherein the disconnection criterion is specifically: the protection device collects instantaneous values of the second analog quantity related to protection during splitting, judges whether the instantaneous value of the second analog quantity is larger than a fixed value of the second analog quantity within the widening time or not, and determines that the instantaneous value of the second analog quantity is larger than the fixed value and meets protection action conditions after time delay.

8. The method as claimed in claim 7, wherein the second analog quantity includes a zero-sequence voltage component difference between both sides of the GCB, a minimum zero-sequence voltage between both sides of the GCB, and a maximum phase current at a generator terminal.

Technical Field

The invention relates to the technical field of relay protection, in particular to a non-full-phase protection logic implementation method of a three-phase linkage type circuit breaker.

Background

Currently, three-phase linked generator outlet circuit breakers (hereinafter referred to as GCBs) are widely used in hydroelectric power plants. However, the GCB may have inconsistent three-phase states during the switching on and off process due to the mechanical structure and frequent operation. At the moment, zero sequence and negative sequence voltage components are generated on two sides of the GCB, and simultaneously, negative sequence current flows through the stator winding, so that a negative sequence magnetic field is generated, the induced frequency doubling current can form local high temperature at a part with larger contact resistance of the rotor, so that the rotor is burnt, and the vibration of a unit is increased due to the existence of the negative sequence magnetic field, so that metal fatigue and mechanical damage can be caused. Because the load of the GCB on the switch-on and switch-off time groups is different, the magnitudes of electric quantities such as zero sequence voltage and negative sequence current are also different when non-full-phase faults occur, the conventional GCB non-full-phase protection only uses the negative sequence current or the zero sequence voltage as a criterion, and the protection is possibly rejected when the GCB non-full-phase faults occur under the condition of small load, so that the design of a multi-criterion and multi-mode GCB non-full-phase protection logic is necessary according to the actual situation of a power plant site.

Disclosure of Invention

The invention aims to provide a non-full-phase protection logic implementation method of a three-phase linkage type circuit breaker to overcome the defects of the prior art.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a non-full-phase protection logic implementation method of a three-phase linkage type circuit breaker comprises the following steps:

step S1: the protection device judges whether to start non-full-phase protection and an energy supply mode of the generator set according to the change of the GCB position contact, wherein the energy supply mode comprises grid connection and disconnection, and the step S2 is executed;

step S2: when the generator set is connected to the grid or disconnected from the grid, respectively adopting a grid connection criterion and a disconnection criterion to judge whether the protection action condition is met, and executing the step S3;

step S3: when any criterion meets the protection action condition, the protection action is stopped or an alarm is given.

Preferably, in step S1, the GCB position contact change is specifically: when the GCB position contact changes into GCB closing or GCB opening, non-full-phase protection is started, when GCB closing is detected, a generator set is connected to the grid, non-full-phase protection is started and the protection time is widened, and when GCB opening is detected, the generator set is disconnected, non-full-phase protection is started and the protection time is widened.

Preferably, the guard time is 300 s.

Preferably, in step S2, if the generator set is connected to the grid, it is determined whether the protection operation condition is satisfied according to a grid connection criterion, and if the generator set is disconnected, it is determined whether the protection operation condition is satisfied according to a disconnection criterion.

Preferably, the grid connection criterion is specifically: the protection device collects a real-time value of a first analog quantity related to grid-connected protection, judges whether the real-time value of the first analog quantity is larger than a fixed value of a second analog quantity within the broadening time, and judges that a protection action condition is met after time delay if the real-time value of the first analog quantity is larger than the fixed value.

Preferably, the first analog quantity comprises a zero-sequence voltage component difference on two sides of the GCB, a minimum zero-sequence voltage on two sides of the GCB, and a minimum negative-sequence current on two sides of the GCB.

Preferably, the disconnection criterion is specifically: the protection device collects instantaneous values of the second analog quantity related to protection during splitting, judges whether the instantaneous value of the second analog quantity is larger than a fixed value of the second analog quantity within the widening time or not, and determines that the instantaneous value of the second analog quantity is larger than the fixed value and meets protection action conditions after time delay.

Preferably, the second analog quantity includes a zero-sequence voltage component difference on two sides of the GCB, a minimum zero-sequence voltage on two sides of the GCB, and a maximum phase current at a generator terminal.

The invention has the beneficial effects that: the invention designs a non-all-phase protection logic realization method of a three-phase linkage type circuit breaker, which takes GCB position contact change as a starting condition and is divided into two modes of unit grid connection and disconnection, wherein the grid connection mode adopts zero sequence voltage component difference, minimum zero sequence voltage and negative sequence current at two sides of GCB as criteria; the invention designs a non-full-phase protection logic which adopts multiple modes and multiple criteria, can meet the actual situation of a power plant field and solves the problem that the existing GCB non-full-phase protection only adopts negative sequence current or zero sequence voltage and the like as single criteria.

Drawings

FIG. 1 is an overall schematic view of the present invention;

FIG. 2 is a flow chart embodying the present invention;

FIG. 3 is a non-full phase protection logic of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to fig. 1 to 3 of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other implementations made by those of ordinary skill in the art based on the embodiments of the present invention are obtained without inventive efforts.

In the description of the present invention, it is to be understood that the terms "counterclockwise", "clockwise", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used for convenience of description only, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be considered as limiting.

As shown in fig. 1, a method for implementing non-full-phase protection logic of a three-phase linkage circuit breaker includes the following steps:

step S1: the protection device judges whether to start non-full-phase protection and an energy supply mode of the generator set according to the change of the GCB position contact, wherein the energy supply mode comprises grid connection and disconnection, and the step S2 is executed;

step S2: when the generator set is connected to the grid or disconnected from the grid, respectively adopting a grid connection criterion and a disconnection criterion to judge whether the protection action condition is met, and executing the step S3;

step S3: when any criterion meets the protection action condition, the protection action is stopped or an alarm is given.

In step S1, the GCB position contact change is specifically: when the GCB position contact changes into GCB closing or GCB opening, non-full-phase protection is started, when GCB closing is detected, a generator set is connected to the grid, non-full-phase protection is started and the protection time is widened, and when GCB opening is detected, the generator set is disconnected, non-full-phase protection is started and the protection time is widened.

It is worth noting that the guard time is 300 s.

It should be noted that, in step S2, if the generator set is connected to the grid, it is determined whether the protection operation condition is satisfied according to the grid connection criterion, and if the generator set is disconnected, it is determined whether the protection operation condition is satisfied according to the disconnection criterion.

It is worth to say that the grid connection criterion is specifically: the protection device collects a real-time value of a first analog quantity related to grid-connected protection, judges whether the real-time value of the first analog quantity is larger than a fixed value of a second analog quantity within the broadening time, and judges that a protection action condition is met after time delay if the real-time value of the first analog quantity is larger than the fixed value.

It should be noted that the first analog quantity includes a zero-sequence voltage component difference between two sides of the GCB, a minimum zero-sequence voltage between two sides of the GCB, and a minimum negative-sequence current between two sides of the GCB.

It should be noted that the disconnection criterion is specifically: the protection device collects instantaneous values of the second analog quantity related to protection during splitting, judges whether the instantaneous value of the second analog quantity is larger than a fixed value of the second analog quantity within the widening time or not, and determines that the instantaneous value of the second analog quantity is larger than the fixed value and meets protection action conditions after time delay.

It should be noted that the second analog quantity includes a zero-sequence voltage component difference between two sides of the GCB, a minimum zero-sequence voltage between two sides of the GCB, and a maximum phase current at a generator terminal.

Specifically, the grid connection criterion and the disconnection criterion include the following formulas:

min(U_H0,U_F0)＞U_set0

min(I_H2,I_F2)＞I_set2

max(I_A,I_B,I_C)＞I_set1

wherein, U_H0、U_F0The three-phase voltage generator is characterized in that the three-phase voltage generator is externally connected with fundamental wave zero sequence voltage on two sides of GCB, IH2 and IF2 are negative sequence currents on two sides of a circuit breaker, IA, IB and IC are three-phase currents at the generator end, K is an internal adjustment coefficient of the device, and U is a voltage value_set0Threshold value, delta U, for external fundamental zero-sequence voltage effective value_set0A zero-sequence voltage component difference value, I, connected to two sides of the circuit breaker_set2For negative sequence current start-up setting, I_set1And setting the maximum phase current of the generator.

Specifically, the method takes the GCB position contact change as a starting condition, is divided into two modes of grid connection and disconnection, is only put into and widened by 300S when a generator is connected to the grid or disconnected, and has the action result of shutdown or alarm. As shown in fig. 3, if the non-full-phase protection hard pressing plate and the control word are put into operation, when the protection device detects the closing of the GCB when the unit is connected to the grid, the non-full-phase protection starts and expands by 300S, at this time, the protection device will judge whether the zero-sequence voltage component difference at both sides of the GCB, the minimum zero-sequence voltage at both sides, and the minimum negative-sequence current at both sides are greater than a fixed value, and if the electrical quantity in 300S is greater than the fixed value at the same time, the non-full-phase protection acts on the shutdown or the alarm after a certain delay. Considering that if a non-full-phase fault occurs when a unit is split, the negative sequence current is very small and may not reach an action fixed value, so that a maximum phase current fixed value at a generator terminal is introduced. If the non-full-phase protection hard pressing plate and the control word are put into operation, when the protection device detects that the GCB is opened when the unit is disconnected, the non-full-phase protection is started and widened by 300S, at the moment, the protection device judges whether the zero-sequence voltage quantity difference at two sides of the GCB, the minimum zero-sequence voltage at two sides and the maximum phase current at the generator end meet fixed values or not, and if the electric quantities in 300S reach the fixed values at the same time, the non-full-phase protection is delayed for a certain time to act on shutdown or alarm.