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CN116365487A - Protection method and device for failure of connecting circuit breaker of hybrid alternating current filter - Google Patents

Protection method and device for failure of connecting circuit breaker of hybrid alternating current filter Download PDF

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Publication number
CN116365487A
CN116365487A CN202310203220.3A CN202310203220A CN116365487A CN 116365487 A CN116365487 A CN 116365487A CN 202310203220 A CN202310203220 A CN 202310203220A CN 116365487 A CN116365487 A CN 116365487A
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CN
China
Prior art keywords
filter
breaker
circuit breaker
current
condition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310203220.3A
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Chinese (zh)
Inventor
张红跃
王攀峰
牛志雷
宋红涛
杜延辉
李宝伟
邓茂军
黄继东
徐立明
崔敏
张乔宾
陈海龙
邹友锋
杜文
张莹
姚德振
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Henan Xujijibao Electric Automation Co ltd
Xuji Group Co Ltd
XJ Electric Co Ltd
Original Assignee
Henan Xujijibao Electric Automation Co ltd
Xuji Group Co Ltd
XJ Electric Co Ltd
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Publication date
Application filed by Henan Xujijibao Electric Automation Co ltd, Xuji Group Co Ltd, XJ Electric Co Ltd filed Critical Henan Xujijibao Electric Automation Co ltd
Priority to CN202310203220.3A priority Critical patent/CN116365487A/en
Publication of CN116365487A publication Critical patent/CN116365487A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
    • H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
    • H02J13/0004—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers involved in a protection system
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention belongs to the technical field of protection of extra-high voltage/high voltage direct current transmission systems, and particularly relates to a protection method and device for failure of a hybrid alternating current filter connection breaker. The action switching-in of the failure protection of the connecting breaker is double switching-in, so that the two switching-in are ensured to be mutually referred, and the situation of misidentification that a single switching-in is difficult to find is avoided; and according to the characteristic that the switching-in has shorter existing time, the failure protection of the connecting breaker is locked in time when the double switching-in exists for a long time, so that the failure protection false triggering of the connecting breaker is avoided. Besides the criterion corresponding to the three-phase current at the starting resistor, the criterion corresponding to the zero sequence current overcurrent and the negative sequence current overcurrent at the starting resistor is additionally arranged, and whether the fault current exists or not can be detected from multiple aspects by providing multiple criteria so as to improve the sensitivity of a detection result; and the newly added criterion can be locked through CT disconnection and corresponding control words, so that the related logic judgment step is omitted when the criterion fails, and the calculation cost is saved.

Description

Protection method and device for failure of connecting circuit breaker of hybrid alternating current filter
Technical Field
The invention belongs to the technical field of protection of extra-high voltage/high voltage direct current transmission systems, and particularly relates to a protection method and device for failure of a hybrid alternating current filter connection breaker.
Background
Along with the continuous improvement of the position of the extra-high voltage direct current engineering in the power transmission system of China, the harmonic problem brought by the extra-high voltage direct current engineering is gradually highlighted, and the serious harmonic exceeding problem appears at the periphery of a landing area of some direct current engineering at present. The hybrid ac filter HAPF in which the passive filter PF and the active filter APF are connected in series meets various compensation requirements, has gradually become a popular research topic in the field of harmonic suppression, and is also a development direction of future filtering technology. As shown in fig. 1, the hybrid alternating current filter (HAPF) includes: in fig. 1, an active filter (i.e., a hybrid ac filter active area) is inside a dashed box, and a passive ac filter (i.e., a hybrid ac filter passive area) is outside the dashed box. The hybrid ac filter is to be started up safely and effectively and put into operation safely on the premise that it functions; when the hybrid alternating current filter is started, a starting resistor R0 is put into operation, after a connecting breaker Q6 is closed, an alternating current power supply charges an inverter through the starting resistor R0, and after the charging is completed, a starting loop breaker Q9 connected with the starting resistor in parallel is closed.
During the starting period of the hybrid ac filter, if a ground fault occurs between the starting resistor R0 and the inverter, and the connection breaker Q6 fails at this time, so that the connection breaker Q6 cannot be tripped, the conventional breaker protection device can determine whether the connection breaker Q6 fails by determining whether the current at the connection breaker is greater than the current set value after receiving the trip signal, and if the connection breaker Q6 fails, the previous-stage breaker Q5 is tripped in a delayed manner. However, since the starting resistor is in the put-in state at this time, the fault current at the connecting breaker is small, and possibly smaller than the current set value for triggering the breaker protection, so that the breaker protection operation is not triggered, and the fault current is small, but is enough to permanently damage the starting resistor for a long time; when the hybrid alternating current filter normally operates (the starting resistor is not put into operation), the existing protection action is to trip the starting circuit breaker Q9 in addition to the tripping connection of the circuit breaker Q6 after the fault occurs, so that the fault current caused by the tripping failure of the connecting circuit breaker Q6 can be prevented from damaging the current converter, the starting resistor is put into operation at the moment, and the situation that the fault current at the connecting circuit breaker is smaller can occur; and directly lowering the current set point triggering the circuit breaker protection will result in an increased false triggering. Therefore, no matter in the starting or normal operation period of the hybrid ac filter, as long as the connection breaker Q6 is malfunctioning, the existing method of judging whether to trigger the failure protection of the connection breaker Q6 directly by judging whether the current at the connection breaker is larger than a fixed value is not enough, which may result in that the failure protection action of the connection breaker cannot be executed in time, so that the starting resistor is damaged due to the influence of the fault current, or false triggering is easy to occur, and the operation efficiency of the hybrid ac filter is affected.
Disclosure of Invention
The invention aims to provide a protection method and a device for the failure of a connecting breaker of a hybrid alternating current filter, which are used for solving the problems that in the prior art, the failure protection action of the connecting breaker cannot be executed in time or the failure protection action of the connecting breaker is easy to trigger by judging whether the current at the connecting breaker is larger than a fixed value or not, and the reliability of the mode of triggering the failure protection of the connecting breaker is insufficient.
In order to achieve the above object, the present invention provides a protection method for a hybrid ac filter connected to a breaker failure, where the hybrid ac filter is formed by connecting a head end of an active filter with a tail end of a passive ac filter, and when four conditions are satisfied at the same time, after a delay time is set, the protection action for the hybrid ac filter connected to the breaker failure is controlled:
condition one: the action of connecting the failure protection of the circuit breaker is started effectively;
condition II: fault current exists at the starting resistor;
and (3) a third condition: the high-voltage circuit breaker is positioned at a closing position;
condition four: the grounding circuit breaker is changed from a switching-off position to a switching-on position;
the connecting breaker is a breaker for connecting an active filter in the hybrid alternating current filter with the tail end of the passive alternating current filter; the starting resistor is a resistor connected in series with an inverter of an active filter in the hybrid alternating current filter; the high-voltage circuit breaker is a circuit breaker which connects the head end of a passive alternating current filter in the mixed alternating current filter with an alternating current bus; the grounding circuit breaker is a circuit breaker for grounding the tail end of a passive filter in the hybrid alternating current filter.
The beneficial effects of the technical scheme are as follows: the fault protection action of the bus area of the hybrid alternating current filter and the fault protection action of the passive area are confirmed to be unsuccessful in isolating faults through the on-off state and the on-off state, so that the follow-up judgment and protection of the failure of the connecting breaker can be correspondingly carried out under the working condition of the fault protection action of the active area, the false triggering of the failure protection action of the connecting breaker of the hybrid alternating current filter is avoided, the reliability of the failure protection action of the connecting breaker of the hybrid alternating current filter is improved, and the influence on a power transmission system is prevented.
Further, the action opening of the connection breaker failure protection is double opening, and the opening amounts of the action opening of the two connection breaker failure protection are the same;
the mode for judging whether the action of connecting the breaker failure protection is effective is as follows: and if the action opening of the failure protection of the two connecting circuit breakers simultaneously exists and the time length of the two opening simultaneously exists does not exceed the set time length threshold, judging that the condition that the action opening of the failure protection of the connecting circuit breakers is effective is met.
The beneficial effects of the technical scheme are as follows: the action opening of the failure protection of the connecting circuit breaker is double opening, and the opening amounts of the two action opening of the failure protection of the connecting circuit breaker are the same, which is equivalent to the arrangement of redundant opening, so that the two opening are mutually referred, and the situation of misidentification that the single opening is difficult to be found is avoided; and according to the characteristic that the switching-in is generally short in existence time, the fault protection of the connecting breaker is locked in time and an alarm is sent out when the double switching-in exists for a long time, and staff is reminded to overhaul in time while the false triggering of the fault protection of the connecting breaker is avoided.
Further, if the CT disconnection blocking failure protection logic starts the input of the control word and determines that the CT disconnection occurs in the three-phase current at the starting resistor, the method for determining whether the condition that the fault current exists at the starting resistor is satisfied is as follows:
if satisfy I a ＞I set 、I b ＞I set Or I c ＞I set If any one of the above conditions is met, judging that the condition that the fault current exists at the starting resistor is met;
wherein I is a 、I b And I c Three-phase currents at the starting resistor respectively; i set A threshold is set for connection breaker failure protection.
Further, if the CT disconnection latch failure protection logic start control word is not input, or if it is determined that the CT disconnection does not occur in the three-phase current at the start resistor, the method for determining whether the condition that the fault current exists at the start resistor is satisfied is as follows:
if satisfy I a ＞I set 、I b ＞I set And I c ＞I set Any one of or satisfy 3I 0 ＞I 0set And I 2 ＞I 2set If any one of the above conditions is met, judging that the condition that the fault current exists at the starting resistor is met;
wherein I is a 、I b And I c Three-phase currents at the starting resistor respectively; i set Setting a phase current threshold; i 0 And I 2 The zero sequence current and the negative sequence current at the starting resistor are respectively; i 0set And I 2set And setting a zero sequence current threshold value and a negative sequence current threshold value respectively.
The beneficial effects of the technical scheme are as follows: in addition to the criteria corresponding to the three-phase current at the starting resistor, the criteria corresponding to the zero sequence current overcurrent and the negative sequence current overcurrent at the starting resistor are additionally arranged, so that whether the fault current exists or not can be detected from multiple aspects by providing multiple criteria, and the sensitivity of a detection result is improved; and to save computation costs as much as possible, the criteria initiates control word latching via CT disconnection and CT disconnection latch failure protection logic.
Further, the mode of judging whether the condition that the high-voltage circuit breaker is at the closing position is:
if the min (I) ha ,I hb ,I hc )＞I YL1 Judging that the condition that the high-voltage circuit breaker is at the closing position is met;
wherein min (I ha ,I hb ,I hc ) The minimum value of the effective values of the current fundamental waves of the phase A, the phase B and the phase C at the head end of the passive alternating current filter; i YL1 A first value of the first presence stream; i YL1 The range of values of (2) is related to the rated current at the passive ac filter.
Further, the way of changing the condition of the grounding breaker from the opening position to the closing position is as follows: if the abrupt pulse edge criterion and the steady state value criterion are met at the same time, judging that the condition that the grounding circuit breaker is changed from the opening position to the closing position is met;
wherein, the abrupt pulse edge criterion is: i.e da (t)-i da (t-2T)＜kI e And i db (t)-i db (t-2T)＜kI e And i dc (t)-i dc (t-2T)＜kI e ；
Wherein i is da (t)、i db (t) and i dc (t) are the effective values of the current fundamental waves of the phase A, the phase B and the phase C at the high-voltage circuit breaker at the current sampling moment, i da (t-2T)、i db (T-2T) and i dc (T-2T) is the effective value of the current fundamental wave of the phase A, the phase B and the phase C at the high-voltage circuit breaker at the sampling time before two sampling periods respectively, k is a coefficient larger than 0, I e Is the rated current at the passive ac filter;
the steady state value criteria are: min (I) da ,I db ,I dc )＞I YL2 ；
Wherein min (I da ,I db ,I dc ) Is the minimum value of the fundamental wave effective values of the phase A, the phase B and the phase C currents at the head end of the active alternating current filter,I YL2 a second value is defined; i YL2 The range of values of (2) is related to the rated current at the passive ac filter.
The beneficial effects of the technical scheme are as follows: the condition that the grounding circuit breaker is changed from the opening position to the closing position is judged to be met, the abrupt pulse edge criterion and the steady state value criterion are met at the same time, the situation that misjudgment does not occur can be guaranteed as far as possible, and the reliability of the judgment result that the grounding circuit breaker is changed from the opening position to the closing position is improved.
Further, the hybrid ac filter connection breaker failure protection action is: high voltage circuit breaker and ground circuit breaker are tripped.
Further, after the condition that the grounding circuit breaker is changed from the opening position to the closing position is met, if the first condition, the second condition and the third condition are met at the same time within the set widening time, the four conditions are judged to be met at the same time.
The beneficial effects of the technical scheme are as follows: the situation that misjudgment occurs due to the fact that the logic judgment result of the condition four is not synchronous with the logic judgment results of the condition one, the condition two and the condition three can be avoided.
Further, the set stretching time is 1 second or more.
The invention also provides a protection device for the failure of the connecting circuit breaker of the hybrid alternating current filter, which comprises a collector and a processor, wherein the collector is used for respectively acquiring corresponding current values of the connecting circuit breaker, the high-voltage circuit breaker, the head end of the passive alternating current filter, the head end of the active filter and the starting resistor, and the processor is used for executing program instructions so as to realize the protection method for the failure of the connecting circuit breaker of the hybrid alternating current filter.
The protection device for the failure of the connecting breaker of the hybrid alternating current filter can achieve the same beneficial effects as the protection method for the failure of the connecting breaker of the hybrid alternating current filter.
Drawings
FIG. 1 is a schematic diagram of a circuit structure of a hybrid AC filter according to the background art of the invention;
fig. 2 is a schematic diagram of a discrimination logic for connection breaker failure protection initiation in an embodiment of a protection method for connection breaker failure of a hybrid ac filter according to the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent.
The embodiment of the protection method for the failure of the connecting breaker of the hybrid alternating current filter comprises the following steps:
the embodiment provides a technical scheme of a protection method for the failure of a connection breaker of a hybrid ac filter, as shown in fig. 1, the hybrid ac filter applicable to the protection method in the embodiment is formed by connecting the head end of an active filter with the tail end of a passive ac filter, the active filter corresponds to an active area of the hybrid ac filter in fig. 1, and similarly, the passive ac filter corresponds to a passive area of the hybrid ac filter in fig. 1; in fig. 1, T4 is a passive area current transformer, and Q5 is a high voltage circuit breaker; t5 is an active area current transformer; q6 is a connecting breaker, T7 is a grounding current transformer, Q7 is a grounding breaker, T6 is a starting loop current transformer, Q9 is a starting loop breaker, G1 is a front ground disconnecting link arranged on the Q6 side of the connecting breaker, G2 is a horizontal double-grounding disconnecting switch, and G3 is a horizontal non-grounding disconnecting switch; r0 is a starting resistor, G4 is a rear ground disconnecting link of a branch circuit where a starting circuit breaker is located, and PT1 and PT2 are circuit voltage transformers;
if the hybrid ac filter bus bar fails, the hybrid ac filter bus bar protection is operated in priority, and the high voltage circuit breakers Q1, Q2, Q3, Q4, Q5 are tripped to isolate the fault. If the passive ac filter fails, the passive ac filter protects the high voltage circuit breaker Q3 or Q4 from being tripped. If the passive region of the hybrid alternating current filter fails, the protection action of the passive region of the hybrid alternating current filter breaks the high-voltage circuit breaker Q5 and simultaneously locks the active alternating current filter. If the active area of the hybrid alternating current filter fails, the protection action of the active area of the hybrid alternating current filter is performed, and in the normal operation process, the active area of the hybrid alternating current filter fails, and the action result is that Q7 is closed and Q6 and Q9 are jumped. Q7 is closed to ensure that the passive region of the hybrid AC filter can still work normally; the tripping Q9 is used for greatly reducing the fault current after the input, so that the safety of the converter is ensured, and the starting resistor is not damaged; the trip Q6 is to cut off the source of the fault current. In the starting process, the active area of the hybrid alternating current filter is failed, and the action result is closing Q7 and tripping Q6. If the connection breaker Q6 fails, the previous stage breaker Q5 needs to be tripped. The fault current is small because of the fault in the starting process; in the normal operation process, the protection action breaks Q9 in addition to Q6, so that the fault current detected by the failure protection is smaller.
In combination with the creative analysis of the above situation, referring to the judgment logic of fig. 2, the protection method for the failure of the hybrid ac filter connection breaker in the present embodiment specifically includes: when the following four conditions are satisfied simultaneously, after the delay time is set, the mixed alternating current filter is controlled to be connected with the breaker for failure protection, and the action result is to trip the high-voltage breaker Q5 and the grounding breaker Q7:
condition one: the action of connecting the failure protection of the circuit breaker is started effectively;
condition II: fault current exists at the starting resistor;
and (3) a third condition: the high-voltage circuit breaker is positioned at a closing position;
condition four: the grounding circuit breaker is changed from a switching-off position to a switching-on position;
the connecting breaker Q6 is a breaker for connecting an active filter in the hybrid alternating current filter with the tail end of the passive alternating current filter; the starting resistor R0 is a resistor connected in series with an inverter of an active filter in the hybrid alternating current filter; the high-voltage circuit breaker Q5 is a circuit breaker for connecting the head end of a passive alternating current filter in the hybrid alternating current filter with an alternating current bus; the grounding breaker is a breaker for grounding the tail end of the passive filter in the hybrid alternating current filter by Q7.
For the first condition, in the embodiment, the action switching-in of the connection breaker failure protection is double switching-in, and the switching-in amounts of the action switching-in of the two connection breaker failure protection are the same, which is equivalent to setting redundant switching-in; the mode for judging whether the action of connecting the breaker failure protection is effective is as follows: the two action opening of the connection breaker failure protection exist simultaneously (wherein the action opening of the connection breaker failure protection is obtained from an action opening joint, the action opening joint refers to an action joint which is output after actions such as differential protection, overcurrent protection, unbalanced protection and the like of an active area protection of a hybrid alternating current filter, one end of the action joint is connected with a positive power supply, the other end of the action joint is connected with an opening terminal of the connection breaker failure protection), and the two simultaneous opening time periods do not exceed a set time period threshold value, and then the condition that the action opening of the connection breaker failure protection is effective is judged to be met; that is, when two accesses exist at the same time, the access is confirmed to be effective, so that the two accesses can be ensured to be mutually referred, and the situation of misidentification that a single access is difficult to be found is avoided; the conditions of the connection breaker failure protection being on, the high voltage breaker being in the on position and the ground breaker being changed from the off position to the on position are essentially to confirm that the passive zone of the hybrid ac filter is in a normal operating state, that the active zone of the hybrid ac filter is in a fault state, and that the active zone protection has issued a trip command. In addition, in the implementation, the time length threshold is set to be 12 seconds, when the double-opening long-term existence of the failure protection action of the connecting breaker Q6 exceeds 12 seconds, the protection action is reported to be open long-term existence, and the failure protection of the connecting breaker is locked, namely the failure protection action of the connecting breaker is not executed any more; since the normal condition is that the opening of the failure protection action of the connection breaker Q6 usually has the characteristic of short existence time, if the double opening exists for a long time, the condition that the double opening exists possibly because of the fault of the opening signal transmission or other reasons is indicated, and in order to avoid the false triggering of the failure protection of the connection breaker, when the double opening of the failure protection action of the connection breaker Q6 exists for a long time, the failure protection of the connection breaker is blocked and an alarm is sent out, so that the staff is reminded to overhaul in time.
For the second condition, three-phase current at the starting resistor R0 acquired by the T5 current transformer is mainly used as a criterion: any one of the three phases of current at the starting resistor is greater than the connection breaker failure protection set threshold, i.eI a ＞I set 、I b ＞I set Or I c ＞I set The method comprises the steps of carrying out a first treatment on the surface of the Wherein I is a 、I b And I c Three-phase currents at the starting resistor respectively; i set A threshold is set for connection breaker failure protection.
According to the characteristics of small fault current and difficult judgment, the embodiment provides various criteria for detecting whether the fault current exists from multiple aspects so as to improve the sensitivity of a detection result; besides the criterion corresponding to the three-phase current at the starting resistor R0, a zero sequence current I at the starting resistor is additionally arranged 0 Overcurrent and negative sequence current I 2 The zero sequence current I at the starting resistor is influenced by the corresponding criterion of overcurrent due to CT disconnection 0 And negative sequence current I 2 The criterion is disabled, so that the calculation cost is saved as far as possible, the criterion is blocked by CT disconnection and corresponding control word, the corresponding control word used for blocking the criterion is a CT disconnection blocking failure protection logic starting control word, the control word can be set into a put-in or out state by the staff according to actual needs, and when put-in, the zero sequence current I at the starting resistor is blocked under the condition of CT disconnection 0 Overcurrent and negative sequence current I 2 The corresponding criterion of overcurrent is that the condition of CT disconnection no longer corresponds to zero sequence current I at the starting resistor when exiting 0 Overcurrent and negative sequence current I 2 The corresponding criterion of overcurrent causes influence; if the CT disconnection locking failure protection logic starts the control word input and judges that the CT disconnection happens to the three-phase current of the starting resistor R0, the zero and negative sequence overcurrent criterion is withdrawn (the criterion is not used as one of the criteria in the condition II any more), and the judgment is only carried out by the three-phase current criterion at the starting resistor; on the contrary, the judgment can be performed by negative sequence overcurrent, zero sequence overcurrent or phase current overcurrent criteria, specifically, the protection logic of the CT disconnection locking failure protects the input of a control word, and the judgment is performed that the three-phase current at the starting resistor is subjected to CT disconnection, and the mode of judging whether the condition that the starting resistor R0 has fault current is satisfied is as follows:
if satisfy I a ＞I set 、I b ＞I set Or I c ＞I set Any one of them is judged to satisfy the startThe condition that fault current exists at the movable resistor, namely, the condition II is met;
wherein I is a 、I b And I c Three-phase currents at the starting resistor respectively; i set A threshold is set for connection breaker failure protection.
If the CT disconnection locking failure protection logic starting control word is not input, or the three-phase current at the starting resistor R0 is judged not to have CT disconnection, the mode of judging whether the condition of fault current at the starting resistor is met is as follows:
if satisfy I a ＞I set 、I b ＞I set And I c ＞I set Any one of or satisfy 3I 0 ＞I 0set And I 2 ＞I 2set If any one of the conditions is met, judging that the condition that the fault current exists at the starting resistor is met, namely, meeting the condition II;
wherein I is a 、I b And I c Three-phase currents at the starting resistor R0 respectively; i set Setting a phase current threshold; i 0 And I 2 The zero sequence current and the negative sequence current at the starting resistor are respectively; i 0set And I 2set And setting a zero sequence current threshold value and a negative sequence current threshold value respectively.
For the third condition, in this embodiment, the manner of determining whether the condition that the high-voltage circuit breaker Q5 is in the closing position is satisfied is as follows:
if the min (I) ha ,I hb ,I hc )＞I YL1 Judging that the condition that the high-voltage circuit breaker Q5 is at the closing position is satisfied;
wherein min (I ha ,I hb ,I hc ) The minimum value of the effective values of the phase A, phase B and phase C current fundamental waves at the head end of the passive alternating current filter, which is acquired by the current transformer T4 in the passive area of the hybrid alternating current filter; i YL1 A first value of the first presence stream; i YL1 The value range of (2) is related to the rated current at the passive alternating current filter; in this embodiment I YL1 The range of the value of (2) is 0.5I e ～0.7I e ，I e The current rating is set for the passive region of the hybrid alternating current filter.
For the fourth condition, in the present embodiment, the manner of the condition that the ground circuit breaker Q7 is changed from the opening position to the closing position is: if the abrupt pulse edge criterion and the steady state value criterion are met at the same time, judging that the condition that the grounding breaker Q7 is changed from the opening position to the closing position is met; meanwhile, the abrupt pulse edge criterion and the steady state value criterion are met, the situation that misjudgment does not occur can be guaranteed as far as possible, and the reliability of the judgment result that the grounding circuit breaker is changed from the opening position to the closing position is improved.
Wherein, the abrupt pulse edge criterion is: i.e da (t)-i da (t-2T)＜kI e And i db (t)-i db (t-2T)＜kI e And i dc (t)-i dc (t-2T)＜kI e ；
Wherein i is da (t)、i db (t) and i dc (t) are the effective values of the current fundamental waves of the phase A, the phase B and the phase C at the high-voltage circuit breaker at the current sampling moment, i da (t-2T)、i db (T-2T) and i dc (T-2T) is the effective value of the current fundamental wave of the phase A, the phase B and the phase C at the high-voltage circuit breaker at the sampling time before two sampling periods respectively, k is a coefficient larger than 0, the value range of k in the embodiment is 0.4-0.6, I is that e Is the rated current at the passive ac filter;
the steady state value criteria are: min (I) da ,I db ,I dc )＞I YL2 ；
Wherein min (I da ,I db ,I dc ) Is the minimum value of the fundamental wave effective values of the phase A, the phase B and the phase C currents at the head end of the active alternating current filter, I YL2 A second value is defined; i YL2 The value range of (2) is related to the rated current at the passive alternating current filter; in this embodiment I YL1 The range of the value of (2) is 0.5I e ～0.7I e ，I e The current rating is set for the passive region of the hybrid alternating current filter.
Because the judgment of whether the condition that the grounding circuit breaker is changed from the opening position to the closing position is met may be faster, that is, the judgment of the condition four may be completed earlier, in order to avoid the situation that the logic judgment result of the condition four is asynchronous with the logic judgment results of the condition one, the condition two and the condition three, so that erroneous judgment occurs, in the embodiment, after the condition that the grounding circuit breaker is changed from the opening position to the closing position is met, if the condition one, the condition two and the condition three are met simultaneously within the set widening time, the condition four conditions are judged to be met simultaneously; the set stretching time is 1 second or more (not less than 1 second).
Hybrid ac filter connection breaker failure protection device embodiment:
the embodiment provides a technical scheme of a protection device for the failure of a hybrid alternating current filter connection breaker, wherein the protection device comprises a collector and a processor; the collector is used for respectively obtaining corresponding current values at the position of the connecting breaker, the position of the high-voltage breaker, the position of the head end of the passive alternating current filter, the position of the head end of the active filter and the position of the starting resistor, and the processor is used for executing program instructions so as to realize the protection method in the embodiment of the protection method for the connecting breaker failure of the hybrid alternating current filter.
Since the specific protection manner and the working principle of the protection device in this embodiment have been described in detail in the above embodiment of the protection method for the failure of the hybrid ac filter connection breaker, the description thereof is omitted herein.
The invention has the following characteristics:
1) The action opening of the failure protection of the connecting circuit breaker is double opening, and the opening amounts of the two action opening of the failure protection of the connecting circuit breaker are the same, which is equivalent to the arrangement of redundant opening, so that the two opening are mutually referred, and the situation of misidentification that the single opening is difficult to be found is avoided; and according to the characteristic that the switching-in is generally short in existence time, the fault protection of the connecting breaker is locked in time and an alarm is sent out when the double switching-in exists for a long time, and staff is reminded to overhaul in time while the false triggering of the fault protection of the connecting breaker is avoided.
2) In addition to the criteria corresponding to the three-phase current at the starting resistor, the criteria corresponding to the zero sequence current overcurrent and the negative sequence current overcurrent at the starting resistor are additionally arranged, so that whether the fault current exists or not can be detected from multiple aspects by providing multiple criteria, and the sensitivity of the detection result is improved.
3) To save the calculation cost as much as possible, the zero sequence current I at the starting resistor 0 Overcurrent and negative sequence current I 2 The corresponding criterion of overcurrent can be locked through CT disconnection and corresponding control words, and a worker can select to enable the criterion not to participate in judging the failure protection of the connection breaker when the criterion is invalid due to CT disconnection, so that the logic judging step related to the criterion is omitted.
4) The condition that the grounding circuit breaker is changed from the opening position to the closing position is judged to be met, the abrupt pulse edge criterion and the steady state value criterion are met at the same time, the situation that misjudgment does not occur can be guaranteed as far as possible, and the reliability of the judgment result that the grounding circuit breaker is changed from the opening position to the closing position is improved.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explanation of the principles of the present invention and are in no way limiting of the invention.

Claims (10)

1. The mixed AC filter is formed by connecting the head end of an active filter with the tail end of a passive AC filter, and is characterized in that when the following four conditions are simultaneously met, after the delay time is set, the mixed AC filter is controlled to be connected with the breaker for failure protection, and the protection method is characterized in that:
condition one: the action of connecting the failure protection of the circuit breaker is started effectively;
condition II: fault current exists at the starting resistor;
and (3) a third condition: the high-voltage circuit breaker is positioned at a closing position;
condition four: the grounding circuit breaker is changed from a switching-off position to a switching-on position;
the connecting breaker is a breaker for connecting an active filter in the hybrid alternating current filter with the tail end of the passive alternating current filter; the starting resistor is a resistor connected in series with an inverter of an active filter in the hybrid alternating current filter; the high-voltage circuit breaker is a circuit breaker which connects the head end of a passive alternating current filter in the mixed alternating current filter with an alternating current bus; the grounding circuit breaker is a circuit breaker for grounding the tail end of a passive filter in the hybrid alternating current filter.
2. The method for protecting a hybrid ac filter connection breaker failure according to claim 1, wherein the action opening of the connection breaker failure protection is double opening, and the opening amounts of the action opening of the two connection breaker failure protection are the same;
the mode for judging whether the action of connecting the breaker failure protection is effective is as follows: and if the action opening of the failure protection of the two connecting circuit breakers simultaneously exists and the time length of the two opening simultaneously exists does not exceed the set time length threshold, judging that the condition that the action opening of the failure protection of the connecting circuit breakers is effective is met.
3. The method for protecting a hybrid ac filter circuit breaker from failure as recited in claim 1, wherein if the CT disconnection latch failure protection logic starts the control word input and it is determined that the three-phase current at the starting resistor is CT disconnected, the method for determining whether the condition that the starting resistor has a fault current is satisfied is as follows:
if satisfy I a ＞I set 、I b ＞I set Or I c ＞I set If any one of the above conditions is met, judging that the condition that the fault current exists at the starting resistor is met;
wherein I is a 、I b And I c Three-phase currents at the starting resistor respectively; i set A threshold is set for connection breaker failure protection.
4. The method for protecting a hybrid ac filter circuit breaker from failure as recited in claim 3 wherein if the CT disconnection latch failure protection logic start control word is not asserted or if the CT disconnection does not occur in the three-phase current at the start resistor, determining whether the condition for the fault current at the start resistor is satisfied is as follows:
if satisfy I a ＞I set 、I b ＞I set And I c ＞I set Any one of or satisfy 3I 0 ＞I 0set And I 2 ＞I 2set If any one of the above conditions is met, judging that the condition that the fault current exists at the starting resistor is met;
wherein I is a 、I b And I c Three-phase currents at the starting resistor respectively; i set Setting a phase current threshold; i 0 And I 2 The zero sequence current and the negative sequence current at the starting resistor are respectively; i 0set And I 2set And setting a zero sequence current threshold value and a negative sequence current threshold value respectively.
5. The method for protecting a hybrid ac filter junction circuit breaker from failure of claim 1, wherein the determining whether the condition of the high voltage circuit breaker in the on position is satisfied is:
if the min (I) ha ,I hb ,I hc )＞I YL1 Judging that the condition that the high-voltage circuit breaker is at the closing position is met;
wherein min (I ha ,I hb ,I hc ) The minimum value of the effective values of the current fundamental waves of the phase A, the phase B and the phase C at the head end of the passive alternating current filter; i YL1 A first value of the first presence stream; i YL1 The range of values of (2) is related to the rated current at the passive ac filter.
6. The method for protecting a hybrid ac filter junction circuit breaker from failure according to claim 1, wherein the condition for changing the ground circuit breaker from the open position to the closed position is as follows: if the abrupt pulse edge criterion and the steady state value criterion are met at the same time, judging that the condition that the grounding circuit breaker is changed from the opening position to the closing position is met;
wherein, the abrupt pulse edge criterion is: i i da (t)|-|i da (t-2T)|＜kI e And |i db (t)|-|i db (t-2T)|＜kI e And |i dc (t)|-|i dc (t-2T)|＜kI e ；
Wherein |i da (t)|、|i db (t) | and |i dc (t) | is the effective value of the current fundamental wave of the phase A, the phase B and the phase C at the high-voltage circuit breaker at the current sampling moment, |i da (t-2T)|、|i db (T-2T) | and |i dc (T-2T) I is the effective value of the current fundamental wave of the phase A, the phase B and the phase C at the high-voltage circuit breaker at the sampling time before two sampling periods respectively, k is a coefficient larger than 0, I e Is the rated current at the passive ac filter;
the steady state value criteria are: min (I) da ,I db ,I dc )＞I YL2 ；
Wherein min (I da ,I db ,I dc ) Is the minimum value of the fundamental wave effective values of the phase A, the phase B and the phase C currents at the head end of the active alternating current filter, I YL2 A second value is defined; i YL2 The range of values of (2) is related to the rated current at the passive ac filter.
7. The method of protecting against a hybrid ac filter junction circuit breaker failure of any of claims 1-6, wherein the hybrid ac filter junction circuit breaker failure protection action is: high voltage circuit breaker and ground circuit breaker are tripped.
8. The method according to claim 6, wherein after the condition that the ground circuit breaker is changed from the opening position to the closing position is satisfied, if the condition one, the condition two and the condition three are simultaneously satisfied within the set widening time, it is determined that the four conditions are simultaneously satisfied.
9. The method for protecting against failure of a hybrid ac filter junction circuit breaker according to claim 8, wherein said set dwell time is 1 second or more.
10. A protection device for a hybrid ac filter connection breaker failure, comprising a collector for obtaining respective current values at the connection breaker, at the high voltage breaker, at the passive ac filter head end, at the active filter head end and at the starting resistor, respectively, and a processor for executing program instructions for implementing a protection method for a hybrid ac filter connection breaker failure according to any one of claims 1-9.
CN202310203220.3A 2023-03-03 2023-03-03 Protection method and device for failure of connecting circuit breaker of hybrid alternating current filter Pending CN116365487A (en)

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CN202310203220.3A CN116365487A (en) 2023-03-03 2023-03-03 Protection method and device for failure of connecting circuit breaker of hybrid alternating current filter

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Application Number Priority Date Filing Date Title
CN202310203220.3A CN116365487A (en) 2023-03-03 2023-03-03 Protection method and device for failure of connecting circuit breaker of hybrid alternating current filter

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