WO2016082593A1 - 一种克服汲出电流对母线差动保护影响的方法 - Google Patents
一种克服汲出电流对母线差动保护影响的方法 Download PDFInfo
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- WO2016082593A1 WO2016082593A1 PCT/CN2015/087922 CN2015087922W WO2016082593A1 WO 2016082593 A1 WO2016082593 A1 WO 2016082593A1 CN 2015087922 W CN2015087922 W CN 2015087922W WO 2016082593 A1 WO2016082593 A1 WO 2016082593A1
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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
- H02H7/28—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 meshed systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
- G06F1/26—Power supply means, e.g. regulation thereof
- G06F1/28—Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2513—Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
Definitions
- the invention belongs to the technical field of power system relay protection, and particularly relates to a method for overcoming the influence of the current drawn on the bus differential protection.
- Busbar protection usually uses the principle of differential protection. Differential protection is widely used because of its simple principle and its influence from oscillation. However, in practical applications, the fault current in the area of the bus differential protection has become a major factor affecting its safety and reliability.
- the invention proposes a countermeasure for the busbar differential protection to overcome the influence of the current drawn.
- the large difference protection is used to determine whether a fault has occurred within its protection range, and the small difference component is used to select the fault bus and to cut it off.
- the double busbars are operated in series and the two busbars are electrically connected through the surrounding power network, when one of the busbars fails and the other power bus has a power supply.
- the fault current supplied by the power supply to the fault point must flow out of the non-faulted bus through a branch connected to the non-faulted bus, and flow to the fault point through the branch connected to the faulty bus, as illustrated in FIG. That is, the current is drawn.
- the present invention provides a method for overcoming the influence of the current drawn on the differential protection of the busbar.
- the double busbar wiring mode it is not necessary to reduce the braking coefficient during the split operation, and the situation may be Appropriately improve the sensitivity of the bus differential protection in the area of the fault, while ensuring the reliability of the fault outside the zone.
- the present invention provides a method for overcoming the effect of a current drawn on a bus differential protection, the method comprising Next steps:
- Step 1 Collecting and processing the branch current signal
- Step 2 Select the fault bus and determine the maximum branch current in the connected branch of the fault bus
- Step 3 Calculate the differential current and braking current of the disparity component and determine whether the disparity component is operating.
- the step 1 includes the following steps:
- Step 1-2 Fourier transforming i j (k) to obtain the current phasor of the jth branch
- the real part X j and the imaginary part Y j have:
- N is the number of sampling points of the fundamental wave in one cycle
- the step 2 includes the following steps:
- Step 2-1 Calculate the differential current and braking current of the small difference component
- the differential current and braking current of the small difference component are represented by I cd small and I zd small , respectively:
- n is the number of all branches connected to the single-segment bus
- Step 2-2 If the differential current and the braking current of the difference component corresponding to a bus bar satisfy I cd small > k res1 I zd is small , it is determined that the bus bar is a fault bus; wherein k res1 is a ratio of the difference component Braking coefficient, usually taken as 0.6;
- Step 2-3 Select the branch current with the largest amplitude in the connected branch of the determined fault bus.
- the step 3 includes the following steps:
- Step 3-1 Calculate the differential current of the difference component, which has:
- I cd is the differential current of the large difference component
- Step 3-2 Calculate the braking current of the difference component, which has:
- I zd is the braking current of the disparity component; a differential current phasor for a large difference component, and
- Step 3-3 Determine whether the difference component is active. If the ratio braking criterion I cd >k res I zd is satisfied, it satisfies:
- k res is the ratio difference braking coefficient of the large difference component, which is 0.8.
- FIG. 1 is a schematic diagram of a current flowing out of a fault in a double busbar wiring area in the prior art
- FIG. 2 is a flow chart of a method for overcoming the influence of the current drawn on the differential protection of the busbar in the embodiment of the present invention.
- the present invention provides a method for overcoming the influence of the current drawn on the differential protection of the busbar.
- the mother differential can be adaptively improved for the case of the output current. It protects the sensitivity of faults in the area while ensuring the reliability of faults outside the zone.
- the method for overcoming the influence of the current drawn on the differential protection of the bus includes the following steps:
- Step 1 Collecting and processing the branch current signal
- Step 2 Select the fault bus and determine the maximum branch current in the connected branch of the fault bus
- Step 3 Calculate the differential current and braking current of the disparity component and determine whether the disparity component is operating.
- the step 1 includes the following steps:
- Step 1-2 Fourier transforming i j (k) to obtain the current phasor of the jth branch
- the real part X j and the imaginary part Y j have:
- N is the number of sampling points of the fundamental wave in one cycle
- the step 2 includes the following steps:
- Step 2-1 Calculate the differential current and braking current of the small difference component
- the differential current and braking current of the small difference component are represented by I cd small and I zd small , respectively:
- n is the number of all branches connected to the single-segment bus
- Step 2-2 If the differential current and the braking current of the difference component corresponding to a bus bar satisfy I cd small > k res1 I zd is small , it is determined that the bus bar is a fault bus; wherein k res1 is a ratio of the difference component Braking coefficient, usually taken as 0.6;
- Step 2-3 Select the branch current with the largest amplitude in the connected branch of the determined fault bus.
- the step 3 includes the following steps:
- Step 3-1 Calculate the differential current of the difference component, which has:
- I cd is the differential current of the large difference component
- Step 3-2 Calculate the braking current of the difference component, which has:
- I zd is the braking current of the disparity component; a differential current phasor for a large difference component, and
- Step 3-3 Determine whether the difference component is active. If the ratio braking criterion I cd >k res I zd is satisfied, it satisfies:
- k res is the ratio difference braking coefficient of the large difference component, which is 0.8.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
一种克服汲出电流对母线差动保护影响的方法,包括以下步骤:支路电流信号采集与处理;选取故障母线,并确定故障母线相连支路中幅值最大支路电流;计算大差元件的差动电流和制动电流,并判断大差元件是否动作。该方法对于双母线接线方式无需在分列运行时降低制动系数,对于有汲出电流的情况可自适应地提高母差保护在区内故障时的灵敏度,同时保证区外故障时的可靠性。
Description
本发明属于电力系统继电保护技术领域,具体涉及一种克服汲出电流对母线差动保护影响的方法。
母线保护通常采用差动保护原理。差动保护由于其原理简单,不受振荡影响诸多优势得到了最广泛的应用。但是,在实际应用中母线差动保护的区内故障汲出电流问题,成为影响其安全性和可靠性的主要因素。本发明提出了母线差动保护克服汲出电流的影响的对策。
对于双母线接线型式的母线保护,通常配置有大差和小差元件。大差保护用来判别是否在其保护范围内发生故障,而小差元件用来选择故障母线,并进行切除。双母线分列运行且两条母线通过周边电力网络形成电气连接时,当其中一条母线故障且另一条健全母线上存在供电电源。此供电电源向故障点提供的故障电流必然通过某一与非故障母线相连接的支路流出非故障母线,并通过与故障母线相连接的支路流向故障点,如说明附图1的即为汲出电流。对于常规比率差动算法,这个电流对大差的差动电流没有影响,却增大了制动电流,从而导致大差比率制动判据的灵敏度下降,在严重的情况下可导致由于大差保护拒动引起的整套母差保护拒动。因此,有的厂家的处理方式为在这种情况下,内部降低大差比率制动系数。对于双母双分段接线型式也存在类似的问题。
发明内容
为了克服上述现有技术的不足,本发明提供一种克服汲出电流对母线差动保护影响的方法,对于双母线接线方式无需在分列运行时降低制动系数,对于有汲出电流的情况可自适应地提高母差保护在区内故障时的灵敏度,同时保证区外故障时的可靠性。
为了实现上述发明目的,本发明采取如下技术方案:
本发明提供一种克服汲出电流对母线差动保护影响的方法,所述方法包括以
下步骤:
步骤1:支路电流信号采集与处理;
步骤2:选取故障母线,并确定故障母线相连支路中幅值最大支路电流;
步骤3:计算大差元件的差动电流和制动电流,并判断大差元件是否动作。
所述步骤1包括以下步骤:
步骤1-1:采集与母线连接的所有支路的电流采样值,并进行低通滤波,得到第j条支路第k次电流采样值ij(k),其中j=1,2,...,n,n为与母线连接的支路总数;
其中,N为基波在一个周期内的采样点数;
所述步骤2包括以下步骤:
步骤2-1:计算小差元件的差动电流和制动电流;
小差元件的差动电流和制动电流分别用Icd小和Izd小表示,有:
其中,m为与单段母线相连接的所有支路数;
步骤2-2:若某母线所对应的小差元件的差动电流和制动电流满足Icd小>kres1Izd小,则确定此母线为故障母线;其中kres1为小差元件的比率制动系数,通常取为0.6;
所述步骤3包括以下步骤:
步骤3-1:计算大差元件差动电流,有:
其中,Icd为大差元件差动电流;
步骤3-2:计算大差元件的制动电流,有:
步骤3-3:判断大差元件是否动作,若满足比率制动判据Icd>kresIzd,即满足:
则表明大差元件动作,否则表明大差元件不动作,其中kres为大差元件比率制动系数,取0.8。
与现有技术相比,本发明的有益效果在于:
2.正常情况或区外故障时,为不平衡电流本发明所提出的判据演化为与常规判据相比,应用新型算法制动量相对
于常规算法有所减小,但是由于为区外故障时的不平衡电流,在CT未饱和的情况下,的值非常小,母线差动保护仍能保证可靠不误动作;
3.通过与典型的母线电流差动判据比较可得,区内故障时,现有典型判据和本发明提出的判据动作量相同,本发明提出的判据制动量不受母线汲出电流的影响,且小于现有判据的制动量因此,本发明提出的判据灵敏度高于现有判据;区外故障时,本发明提出的判据与现有判据具有基本相同的可靠性。
图1是现有技术中双母线接线区内故障存在汲出电流示意图;
图2是本发明实施例中克服汲出电流对母线差动保护影响的方法流程图。
下面结合附图对本发明作进一步详细说明。
如图2,本发明提供一种克服汲出电流对母线差动保护影响的方法,对于双母线接线方式无需在分列运行时降低制动系数,对于有汲出电流的情况可自适应地提高母差保护在区内故障时的灵敏度,同时保证区外故障时的可靠性。
克服汲出电流对母线差动保护影响的方法包括以下步骤:
步骤1:支路电流信号采集与处理;
步骤2:选取故障母线,并确定故障母线相连支路中幅值最大支路电流;
步骤3:计算大差元件的差动电流和制动电流,并判断大差元件是否动作。
所述步骤1包括以下步骤:
步骤1-1:采集与母线连接的所有支路的电流采样值,并进行低通滤波,得到第j条支路第k次电流采样值ij(k),其中j=1,2,...,n,n为与母线连接的支路总数;
其中,N为基波在一个周期内的采样点数;
所述步骤2包括以下步骤:
步骤2-1:计算小差元件的差动电流和制动电流;
小差元件的差动电流和制动电流分别用Icd小和Izd小表示,有:
其中,m为与单段母线相连接的所有支路数;
步骤2-2:若某母线所对应的小差元件的差动电流和制动电流满足Icd小>kres1Izd小,则确定此母线为故障母线;其中kres1为小差元件的比率制动系数,通常取为0.6;
所述步骤3包括以下步骤:
步骤3-1:计算大差元件差动电流,有:
其中,Icd为大差元件差动电流;
步骤3-2:计算大差元件的制动电流,有:
步骤3-3:判断大差元件是否动作,若满足比率制动判据Icd>kresIzd,即满足:
则表明大差元件动作,否则表明大差元件不动作,其中kres为大差元件比率制动系数,取0.8。
最后应当说明的是:以上实施例仅用以说明本发明的技术方案而非对其限制,所属领域的普通技术人员参照上述实施例依然可以对本发明的具体实施方式进行修改或者等同替换,这些未脱离本发明精神和范围的任何修改或者等同替换,均在申请待批的本发明的权利要求保护范围之内。
Claims (4)
- 一种克服汲出电流对母线差动保护影响的方法,其特征在于:所述方法包括以下步骤:步骤1:支路电流信号采集与处理;步骤2:选取故障母线,并确定故障母线相连支路中幅值最大支路电流;步骤3:计算大差元件的差动电流和制动电流,并判断大差元件是否动作。
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CN115313304A (zh) * | 2022-06-30 | 2022-11-08 | 南京理工大学 | 一种应用于5g下含分支线的架空线路差动保护方法 |
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CN104393579B (zh) * | 2014-11-26 | 2017-02-22 | 国家电网公司 | 一种克服汲出电流对母线差动保护影响的方法 |
CN105470931B (zh) * | 2015-12-25 | 2017-12-26 | 国家电网公司 | 一种不受母线数据不同步影响的母线差动保护方法 |
CN105870887B (zh) * | 2016-05-04 | 2018-04-20 | 国电南瑞科技股份有限公司 | 一种识别母线差动区域的方法 |
CN109188207B (zh) * | 2018-09-18 | 2020-12-25 | 四川理工学院 | 一种基于初始行波有功功率的母线故障定位方法 |
CN114498557A (zh) * | 2021-12-29 | 2022-05-13 | 北京四方继保工程技术有限公司 | 适用于母联ct断线情况下的自适应的区外ct饱和判别方法 |
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CN101609979A (zh) * | 2009-07-24 | 2009-12-23 | 南京南瑞继保电气有限公司 | 面向对象的母线保护设置方法 |
CN103746350A (zh) * | 2014-01-23 | 2014-04-23 | 国家电网公司 | 高灵敏度母线差动保护方法 |
CN104393579A (zh) * | 2014-11-26 | 2015-03-04 | 国家电网公司 | 一种克服汲出电流对母线差动保护影响的方法 |
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CN101609979A (zh) * | 2009-07-24 | 2009-12-23 | 南京南瑞继保电气有限公司 | 面向对象的母线保护设置方法 |
CN103746350A (zh) * | 2014-01-23 | 2014-04-23 | 国家电网公司 | 高灵敏度母线差动保护方法 |
CN104393579A (zh) * | 2014-11-26 | 2015-03-04 | 国家电网公司 | 一种克服汲出电流对母线差动保护影响的方法 |
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CN115313304A (zh) * | 2022-06-30 | 2022-11-08 | 南京理工大学 | 一种应用于5g下含分支线的架空线路差动保护方法 |
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