WO2005078886A1 - A zero-sequence current braking method for power transformer differential protection - Google Patents

A zero-sequence current braking method for power transformer differential protection Download PDF

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Publication number
WO2005078886A1
WO2005078886A1 PCT/CN2005/000194 CN2005000194W WO2005078886A1 WO 2005078886 A1 WO2005078886 A1 WO 2005078886A1 CN 2005000194 W CN2005000194 W CN 2005000194W WO 2005078886 A1 WO2005078886 A1 WO 2005078886A1
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Prior art keywords
zero
current
transformer
differential protection
phase
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PCT/CN2005/000194
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French (fr)
Chinese (zh)
Inventor
Xidong Xu
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Zhejiang University
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Priority claimed from CNB2004100163128A external-priority patent/CN100413169C/en
Priority claimed from CNB2004100163113A external-priority patent/CN100367600C/en
Priority claimed from CNB2004100163058A external-priority patent/CN100388581C/en
Application filed by Zhejiang University filed Critical Zhejiang University
Publication of WO2005078886A1 publication Critical patent/WO2005078886A1/en

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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
    • H02H7/04—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 transformers
    • H02H7/045—Differential protection of transformers

Definitions

  • the invention belongs to the differential protection of a transformer, and in particular relates to a zero-sequence current braking method for the differential protection of a transformer. Background technique
  • the longitudinal differential protection of power transformers currently used consists of two parts: differential quick-break and ratio differential.
  • the power transformer is composed of A, B, and C three phases.
  • Figure 1 is a one-phase protection block diagram. From Figure 1, it can be seen that ratio differential consists of ratio braking, exciting inrush current detection, and overexcitation detection unit.
  • the output of the detection unit is connected to the AND gate after the inverter, and the output of the ratio braking is braked.
  • Figure 2 The longitudinal difference protection uses a current transformer pair Y.
  • the three-phase current on the side (that is, the transformer star connection side where the neutral point is directly grounded) is ⁇ / ⁇ transformed to eliminate the effect of the zero-sequence current. After the transformation, each current no longer contains the zero-sequence component of the primary current.
  • the currents flowing in the three differential coils Wd are A, B, and C three-phase differential currents; Phase currents are combined in other ways to obtain three-phase braking currents, such as: Wresl ⁇ Wres3 are the braking coils on each side, and the maximum current in the three braking coils of the same phase is taken as the braking current; The current in each brake coil is weighted and summed to obtain the braking current of this phase. The braking current thus obtained can only represent the magnitude of the through current.
  • transformer differential protection is Y.
  • the side current transformer is all-star wiring
  • the Yc side three-phase secondary current is ⁇ / ⁇ transformed in the protection device, or the Y Q side three-phase secondary current is subtracted from the zero-sequence current.
  • ⁇ / ⁇ conversion is performed on the secondary current on the ⁇ side, thereby eliminating the influence of the zero-sequence current. It can be seen that after these transformations and the balance of each side adjustment, the differential current obtained by adding the same name and the braking current obtained by other combinations also do not include the zero-sequence component of the primary current, and can only represent the magnitude of the passing current. .
  • the problem is: When the transformer has an external ground fault on the Y Q side and only that side has power, a large zero sequence fault current will appear on the Y Q side, but the fault current does not pass through the transformer. If Y Q-side three-phase current transformer mass becomes inconsistent error, in a three-phase current transformer after converting the three-phase side zero sequence current equal to, not equal to the secondary current, the above-described conventional three-phase current side converting Y Q The method cannot completely eliminate the influence of the zero-sequence current, and will generate an unbalanced current in the differential circuit. Because no fault current flows through the transformer at this time, the braking current obtained by the traditional method is very small and will not exceed the braking current before the fault.
  • the technical problem to be solved by the present invention is directed to the problems existing in the prior art transformer differential protection technology.
  • the three-phase current conversion method cannot completely eliminate the influence of the zero-sequence current, and provides a zero-sequence current braking method for transformer differential protection.
  • the principle is to use a phase differential current in the transformer longitudinal differential protection and the zero sequence current on the Yc side of the transformer to constitute the phase zero sequence ratio braking unit.
  • the ratio value is less than the setting value K, the phase braking signal is output, and the corresponding phase is output.
  • Proportional differential protection applies braking.
  • This zero-sequence current braking method for transformer differential protection is characterized in that: a phase differential current and a Yo-side zero-sequence current in the transformer longitudinal differential protection are used to constitute a phase zero-sequence ratio braking unit.
  • the phase braking signal is output to brake the corresponding phase-ratio differential protection unit; the zero-sequence braking is based on the following relationship:
  • I dx is any phase differential current of the transformer differential protection differential current (I da , I db , I de ), and (3 1) is Y.
  • the side zero-sequence current that is, the sum of the three-phase currents on the side; In the case where the zero-sequence current and the three-phase differential current are reduced to the same side, the range of the setting value K is:
  • 3 1. (3I 10 , 3I 20 , 3I no ) max
  • 3I 1 () , 3I 2 ... 3I nQ ) are each Y.
  • the zero-sequence current on the side (3I 1 () , 3I 2 ..., 3I no ) max is the maximum value of the zero-sequence current on each Y Q side.
  • 3 I. 3I 10 Xk 10 + 3I 20 Xk 20 + ⁇ ⁇ + 3I no X k n0
  • the zero sequence current (3I 1 (), 3 ⁇ 20 , ⁇ ⁇ 3 ⁇ ⁇ ) Y Q for the side, (k 1Q, k 20, ising k n0) is the weight value set in advance
  • (3I 1 () Xk 1 () + 3I 20 Xk 20 + whil + 3I no X k n0 ) is the weighted sum of the zero-sequence currents at each Y 0 side.
  • the zero-sequence current braking method for transformer differential protection of the present invention adds a zero-sequence braking unit on the basis of traditional transformer longitudinal differential protection to form a single-phase zero-sequence ratio braking system.
  • the ratio value is smaller than the setting value ⁇
  • the phase braking signal is output to brake the corresponding phase ratio differential protection.
  • the outstanding effect of this method is that it can completely avoid the misoperation of the transformer longitudinal differential protection caused by the external ground fault in the Y Q side zone when the errors of the three-phase current transformers are inconsistent; it can also prevent the zero-sequence current caused by other non-internal fault conditions.
  • the differential protection of transformer caused by the differential unbalanced current does not work properly, and it does not affect the correct operation of the differential protection in the case of a fault in the area.
  • Figure 1 is a principle block diagram of a transformer longitudinal differential protection device based on the existing method.
  • Figure 2 is the wiring diagram of the transformer longitudinal differential protection device based on the existing method.
  • FIG. 3 is a circuit block diagram of a braking unit according to an embodiment of the method of the present invention.
  • FIG. 4 is a circuit block diagram of a braking unit of the method of the present invention under multiple Y Q side conditions.
  • FIG. 5 is a circuit block diagram of a second embodiment of a braking unit of the method of the present invention under multiple Y Q side conditions. detailed description
  • FIG. 3 provides a circuit device of a zero-sequence current braking unit for transformer differential protection.
  • This device is composed of filters 11 to 13, filter 01, multiplier 2, and comparators 31 to 33, where the inputs of the filters 11 to 13 are respectively input
  • the three-phase differential current signals i da , i db , i dco formed by the transformer longitudinal differential protection are the three-phase differential current instantaneous voltage drops caused by the current flowing through the three Wd in Figure 2.
  • the input of the filter 01 is input to the transformer Y. Side zero sequence current instantaneous value signal 3i.
  • the output terminal is connected to one input terminal of multiplier 2, the other input terminal of multiplier 2 inputs the setting value K, the negative input terminals of comparators 31 to 33 are connected to the output terminals of multiplier 2, and its positive input terminals are respectively Connected to the output terminals of the filters 11 ⁇ 13, the comparators 31 ⁇ 33 output the braking signals of phase A, B and C respectively.
  • the braking signals are directly connected to the AND gate inputs of the differential parts of the comparison ratios, that is, they are connected from part A in Figure 1, and participate in the contrast ratio together with the inrush current and the reverse signal output from the over-excitation detection unit.
  • the output signal of the braking unit is used for braking.
  • the comparator When the positive input signal in the comparators 31 to 33 is less than the negative input signal, the comparator outputs 0 (low potential) and outputs the corresponding phase braking signal to brake the corresponding phase ratio differential protection to prevent the transformer differential protection. Misoperation; otherwise the comparator output 1 (high potential) allows the corresponding ratio differential protection action.
  • the setting value K is 0.1.
  • Fig. 4 shows another embodiment for implementing zero sequence braking.
  • the device is composed of filters 01, 02, 03, filters 11 to 13, a maximum value calculating circuit 4, a multiplier 2, and a comparator 31 to 33, wherein the input terminals of the filters 01, 02, and 03 are respectively input to each of the transformers.
  • the zero-sequence current instantaneous value signals 3i 1Q and 3i 20 3i 3Q of the ground point (or branch) of the neutral point are connected to the input terminal of the maximum-calculation circuit 4 respectively, and one input terminal of the multiplier 2 is connected to the maximum value.
  • the output of circuit 4 has the other input to set value K.
  • the negative input of comparators 31 to 33 is connected to the output of multiplier 2.
  • the inputs of filters 11 to 13 are input from the transformer differential protection.
  • the instantaneous value signals of three-phase differential currents i da , i db , i dc are connected to the positive input terminals of comparators 31 to 33 respectively, and the comparators 31 to 33 respectively output the phases A, B, and C. Action signal.
  • the comparator When the positive input signal in the comparators 31 ⁇ 33 is less than the negative input signal, the comparator outputs 0 and outputs the corresponding phase braking signal to brake the corresponding phase ratio differential protection to prevent the transformer differential protection from malfunctioning; otherwise Comparator output 1 allows corresponding ratio differential protection action.
  • the setting value K is 0.1.
  • FIG. 5 shows still another embodiment of the zero-sequence braking method.
  • the device of the embodiment is composed of filters 01, 02, 03, multipliers 41, 42, 43, adder 5, multiplier 2, filters 11 to 13, and comparators 31 to 33, of which filters 01, 02, and 03
  • the input terminals input the instantaneous zero-sequence current signals 3i 1Q and 3i 2 of the neutral side (or branch) of each transformer.
  • the outputs of filters 11 to 13 are compared with The positive input terminals of the comparators 31 to 33 are connected to each other, and the comparators 31 to 33 output brake signals of phase A, phase B, and phase C, respectively.
  • the setting value K is 0.1.
  • the comparator When the positive input signal in the comparators 31 to 33 is less than the negative input signal, the comparator outputs 0 and outputs the corresponding phase braking signal to brake the corresponding phase ratio differential protection to prevent the transformer differential protection from malfunctioning; otherwise Comparator output 1 allows corresponding ratio differential protection action.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Protection Of Transformers (AREA)

Abstract

The invention discloses a technical improved solution of transformer differential protection. A phase zero-sequence ratio braking unit is formed by using one phase differential current in transformer longitudinal differential protection and the zero-sequence current in Y 0 side of the transformer, the phase braking signal is outputted so that the corresponding phase ratio differential unit of transformer longitudinal differential protection is braked when the ratio value is less than the correcting value K. It can prevent the mal-operation of transformer longitudinal differential protection caused by ground fault outside the Y0 side region, while the normal operation of longitudinal differential protection in the region under the fault is not affected. It is suitable for the longitudinal differential protection of power transformer.

Description

用于变压器差动保护的零序电流制动方法 技术领域  Zero sequence current braking method for transformer differential protection TECHNICAL FIELD
本发明属于变压器的差动保护， 具体地说是一种用于变压器差动保 护的零序电流制动方法。 背景技术  The invention belongs to the differential protection of a transformer, and in particular relates to a zero-sequence current braking method for the differential protection of a transformer. Background technique
目前采用的电力变压器纵差保护由差动速断与比率差动两个部分构 成。依据中华人民共和国电力行业标准 DL/T684-1999《大型发电机变压 器继电保护整定计算导则》（26页）， 变压器纵差保护框图、 纵差保护原 理接线示例如其图 1、 图 2所示。 电力变压器由 A、 B、 C三相构成， 图 1为一相的保护框图， 从图 1 中可知： 比率差动又由比率制动、 励磁涌 流检测、 过励磁检测单元构成， 涌流与过励磁检测单元的输出经反向器 后连到 "与门 "，对比率制动的输出进行制动。 从图 2可知： 纵差保护利 用了电流互感器对 Y。侧（即： 中性点直接接地的变压器星型接线侧）三 相电流进行 Υ/ Δ变换， 以消除零序电流的影响。 经过变换之后， 各电流 已不包含一次电流中的零序分量。 这些电流经中间电流互感器 ΤΑΜ1〜 ΤΑΜ6调平衡， 各同名相电流相加得到三相差动电流， 如： 三个差动线 圈 Wd中流过的电流分别为 A、 B、 C三相差动电流； 同名相电流再进行 其它方式组合得到三相制动电流， 如： Wresl〜Wres3分别为各侧的制动 线圈， 取出同一相三个制动线圈中的最大电流作为制动电流； 或者对同 一相三个制动线圈中的电流滤波后进行加权求和得到该相的制动电流。 如此获得的制动电流只能代表穿越电流的大小。  The longitudinal differential protection of power transformers currently used consists of two parts: differential quick-break and ratio differential. According to the People's Republic of China Electric Power Industry Standard DL / T684-1999 "Guidelines for Calculation and Calculation of Relay Protection Setting for Large Generators and Transformers" (page 26), the block diagram of the transformer longitudinal differential protection and the wiring example of the principle of longitudinal differential protection are shown in Figures 1 and 2. . The power transformer is composed of A, B, and C three phases. Figure 1 is a one-phase protection block diagram. From Figure 1, it can be seen that ratio differential consists of ratio braking, exciting inrush current detection, and overexcitation detection unit. Inrush and overexcitation The output of the detection unit is connected to the AND gate after the inverter, and the output of the ratio braking is braked. It can be seen from Figure 2: The longitudinal difference protection uses a current transformer pair Y. The three-phase current on the side (that is, the transformer star connection side where the neutral point is directly grounded) is Υ / Δ transformed to eliminate the effect of the zero-sequence current. After the transformation, each current no longer contains the zero-sequence component of the primary current. These currents are balanced by the intermediate current transformers TAM1 ~ TAM6, and the currents of the same phase are added to obtain three-phase differential currents, such as: The currents flowing in the three differential coils Wd are A, B, and C three-phase differential currents; Phase currents are combined in other ways to obtain three-phase braking currents, such as: Wresl ~ Wres3 are the braking coils on each side, and the maximum current in the three braking coils of the same phase is taken as the braking current; The current in each brake coil is weighted and summed to obtain the braking current of this phase. The braking current thus obtained can only represent the magnitude of the through current.
变压器纵差保护方式中存在的另外一种是 Y。侧电流互感器为全星 型接线的情况， 此时， 在保护装置内对 Yc侧三相二次电流进行 Υ/ Δ变 换，或者将 YQ侧三相二次电流分别减去零序电流的同时，对 Δ侧二次电 流进行 Δ /Υ变换， 依此消除零序电流的影响。 可见， 通过这些变换并经 各侧调平衡后， 由同名相相加得到的差动电流及通过其它组合得到的制 动电流同样不包含一次电流中的零序分量， 只能代表穿越电流的大小。 问题在于： 当变压器在 YQ侧发生区外接地故障且只有该侧有电源 时， YQ侧将出现很大的零序故障电流， 但该故障电流并未穿越变压器。 若 YQ侧三相电流互感器传变误差不一致时，在一次侧三相相等的零序电 流经三相电流互感器变换后，二次电流不相等，上述传统的 YQ侧三相电 流变换方法不能完全消除零序电流的影响， 将在差动回路产生不平衡电 流。 又因为此时无故障电流穿越变压器， 由上述传统方法获得的制动电 流很小， 不会超过故障前的制动电流， 只要差动回路产生的不平衡电流 超过差动门槛， 变压器纵差保护将发生误动。简言之， 由于 Y。侧零序故 障电流的存在， 将导致差动回路产生不平衡电流， 在没有相应的制动电 流对其进行制动时， 将使得变压器纵差保护误动作的可能性大为提高， 使电力变压器纵差保护的选择性要求得不到满足。 发明内容 Another type of transformer differential protection is Y. In the case where the side current transformer is all-star wiring, at this time, the Yc side three-phase secondary current is Υ / Δ transformed in the protection device, or the Y Q side three-phase secondary current is subtracted from the zero-sequence current. At the same time, Δ / Υ conversion is performed on the secondary current on the Δ side, thereby eliminating the influence of the zero-sequence current. It can be seen that after these transformations and the balance of each side adjustment, the differential current obtained by adding the same name and the braking current obtained by other combinations also do not include the zero-sequence component of the primary current, and can only represent the magnitude of the passing current. . The problem is: When the transformer has an external ground fault on the Y Q side and only that side has power, a large zero sequence fault current will appear on the Y Q side, but the fault current does not pass through the transformer. If Y Q-side three-phase current transformer mass becomes inconsistent error, in a three-phase current transformer after converting the three-phase side zero sequence current equal to, not equal to the secondary current, the above-described conventional three-phase current side converting Y Q The method cannot completely eliminate the influence of the zero-sequence current, and will generate an unbalanced current in the differential circuit. Because no fault current flows through the transformer at this time, the braking current obtained by the traditional method is very small and will not exceed the braking current before the fault. As long as the unbalance current generated by the differential circuit exceeds the differential threshold, the transformer longitudinal differential protection Misoperation will occur. In short, due to Y. The existence of the side zero sequence fault current will cause an unbalanced current to be generated in the differential circuit. When there is no corresponding braking current to brake it, the possibility of misoperation of the transformer differential protection will be greatly improved, which will make the power transformer The selectivity requirements for longitudinal differential protection have not been met. Summary of the invention
本发明要解决的技术问题是针对现有变压器纵差保护技术中存在的 Υ。侧三相电流变换方法不能完全消除零序电流的影响， 提供一种用于变 压器差动保护的零序电流制动方法。  The technical problem to be solved by the present invention is directed to the problems existing in the prior art transformer differential protection technology. The three-phase current conversion method cannot completely eliminate the influence of the zero-sequence current, and provides a zero-sequence current braking method for transformer differential protection.
其原理是用变压器纵差保护中的一相差动电流与变压器 Yc侧零序 电流构成该相零序比率制动单元， 当比率值小于整定值 K时， 输出该相 制动信号， 对相应相比率差动保护进行制动。  The principle is to use a phase differential current in the transformer longitudinal differential protection and the zero sequence current on the Yc side of the transformer to constitute the phase zero sequence ratio braking unit. When the ratio value is less than the setting value K, the phase braking signal is output, and the corresponding phase is output. Proportional differential protection applies braking.
这种用于变压器差动保护的零序电流制动方法， 其特征在于： 用变 压器纵差保护中的一相差动电流与变压器 Yo侧零序电流构成该相零序 比率制动单元， 当比率值小于整定值 K时， 输出该相制动信号， 对相应 相比率差动保护单元进行制动； 零序制动依据以下关系：  This zero-sequence current braking method for transformer differential protection is characterized in that: a phase differential current and a Yo-side zero-sequence current in the transformer longitudinal differential protection are used to constitute a phase zero-sequence ratio braking unit. When the value is smaller than the setting value K, the phase braking signal is output to brake the corresponding phase-ratio differential protection unit; the zero-sequence braking is based on the following relationship:
I dx 3 I。<K  I dx 3 I. <K
式中 I dx为变压器纵差保护差动电流 （ I da、 I db、 I de) 中的任意一相 差动电流， （3 1。） 为 Y。侧零序电流（即该侧三相电流之和）； 在零序电 流与三相差动电流归算到同一侧的情况下， 整定值 K的范围为： In the formula, I dx is any phase differential current of the transformer differential protection differential current (I da , I db , I de ), and (3 1) is Y. The side zero-sequence current (that is, the sum of the three-phase currents on the side); In the case where the zero-sequence current and the three-phase differential current are reduced to the same side, the range of the setting value K is:
0<K < 1/3 ο  0 <K <1/3 ο
本发明方法中当变压器存在多个 Υο侧时， 3 1。 的表达式为- 3 1。= (3I10、 3I20、 3Ino) max 式中 （3I1()、 3I2。、 …… 3InQ)为各 Y。侧的零序电流， （3I1()、 3I2。、 ……、 3Ino) max为各 YQ侧的零序电流中的最大值。 In the method of the present invention, when there are multiple 侧 ο sides of the transformer, 3 1. The expression is-3 1. = (3I 10 , 3I 20 , 3I no ) max In the formula (3I 1 () , 3I 2 ... 3I nQ ) are each Y. The zero-sequence current on the side (3I 1 () , 3I 2 ..., 3I no ) max is the maximum value of the zero-sequence current on each Y Q side.
本发明方法中当变压器存在多个 YQ侧时， 3 1。 的表达式为： In the method of the present invention, when there are multiple Y Q sides of the transformer, 31. The expression is:
3 I。=3I10 Xk10+ 3I20Xk20 + ··· ··· + 3InoX kn0 3 I. = 3I 10 Xk 10 + 3I 20 Xk 20 + ··· ·· + 3I no X k n0
式中（3I1()、 3Ι20、 ··· ··· 3Ιηο)为各 YQ侧的零序电流， （k1Q、 k20、 …… kn0) 为预先设定的权值， （3I1()Xk1() + 3I20Xk20 + …… + 3Ino X kn0) 为各 Y0 侧的零序电流的加权求和值， 当零序电流与三相差动电流归算到同一侧 及权值在 0< (k10、 k2()、 …… kn0) 1的情况下， 整定值 K为 0<K< 1/3。 Wherein the zero sequence current (3I 1 (), 3Ι 20 , ··· ··· 3Ι ηο) Y Q for the side, (k 1Q, k 20, ...... k n0) is the weight value set in advance, (3I 1 () Xk 1 () + 3I 20 Xk 20 + …… + 3I no X k n0 ) is the weighted sum of the zero-sequence currents at each Y 0 side. When the zero-sequence current and the three-phase differential current are calculated To the same side and the weight is 0 <(k 10 , k 2 () ,... K n0 ) 1, the setting value K is 0 <K <1/3.
本发明的用于变压器差动保护的零序电流制动方法， 在传统变压器 纵差保护的基础上， 添加了一个零序制动单元， 组成单相零序比率制动 ***。当比率值小于整定值 κ时，输出该相制动信号，对相应相比率差动 保护进行制动。 本方法的突出效果是， 可完全避免三相电流互感器误差 不一致时， 因 YQ侧区外接地故障导致的变压器纵差保护误动；也可防止 其他非内部故障情况下， 零序电流造成的差动不平衡电流导致的变压器 纵差保护误动作， 且不影响区内故障情况下纵差保护的正确动作。 附图说明 The zero-sequence current braking method for transformer differential protection of the present invention adds a zero-sequence braking unit on the basis of traditional transformer longitudinal differential protection to form a single-phase zero-sequence ratio braking system. When the ratio value is smaller than the setting value κ, the phase braking signal is output to brake the corresponding phase ratio differential protection. The outstanding effect of this method is that it can completely avoid the misoperation of the transformer longitudinal differential protection caused by the external ground fault in the Y Q side zone when the errors of the three-phase current transformers are inconsistent; it can also prevent the zero-sequence current caused by other non-internal fault conditions. The differential protection of transformer caused by the differential unbalanced current does not work properly, and it does not affect the correct operation of the differential protection in the case of a fault in the area. BRIEF DESCRIPTION OF THE DRAWINGS
图 1为基于现有方法的变压器纵差保护装置的原理框图。  Figure 1 is a principle block diagram of a transformer longitudinal differential protection device based on the existing method.
. 图 2为基于现有方法的变压器纵差保护装置的接线原理图。  Figure 2 is the wiring diagram of the transformer longitudinal differential protection device based on the existing method.
图 3为本发明方法实施例的制动单元电路框图。  FIG. 3 is a circuit block diagram of a braking unit according to an embodiment of the method of the present invention.
图 4为本发明方法在多个 YQ侧条件下制动单元的电路框图。 FIG. 4 is a circuit block diagram of a braking unit of the method of the present invention under multiple Y Q side conditions.
图 5为本发明方法在多个 YQ侧条件下制动单元实施例之二的电路框 图。 具体实施方式 5 is a circuit block diagram of a second embodiment of a braking unit of the method of the present invention under multiple Y Q side conditions. detailed description
实施例 1：  Example 1:
参见图 1、 2、 3。 图 3所示实施例给出了一种用于变压器差动保护 的零序电流制动单元的电路装置。 该装置由滤波器 11〜13、 滤波器 01、 乘法器 2、 比较器 31〜33构成， 其中滤波器 11〜13的输入端分别输入 变压器纵差保护形成的 、 B、 C三相差动电流瞬时值信号 ida、 idb、 idco 图 2中三个 Wd中流过的电流流经电阻产生的压降即分别为三相差动电 流瞬时值信号。 滤波器 01的输入端输入变压器 Y。侧零序电流瞬时值信 号 3i。， 其输出端接乘法器 2的一个输入端， 乘法器 2的另一个输入端输 入整定值 K， 比较器 31〜33的负输入端与乘法器 2的输出端相连接，其 正输入端分别接滤波器 11〜13 的输出端， 比较器 31〜33分别输出 Α、 B、 C相的制动信号。 制动信号分别直接接入各相比率差动部分的 "与 门"输入端， 即从图 1 中的 A部位接入， 并与励磁涌流、 过励磁检测单 元输出的反向信号一起参与对比率制动单元的输出信号进行制动。 当比 较器 31〜33中的正输入端信号小于负输入端信号， 比较器输出 0 (低电 位） ， 输出相应相制动信号， 对相应相比率差动保护进行制动， 防止变 压器纵差保护误动； 否则比较器输出 1 (高电位） ， 允许相应相比率差动 保护动作。在差动电流与零序电流均归算到同一侧、同一变比的情况下， 整定值 K为 0.1。 应用本发明方法装置， 可完全避免 Y。侧区外接地故障 导致的变压器纵差保护误动， 且不影响区内故障情况下纵差保护的正确 动作。 实施例 2: See Figures 1, 2, and 3. The embodiment shown in FIG. 3 provides a circuit device of a zero-sequence current braking unit for transformer differential protection. This device is composed of filters 11 to 13, filter 01, multiplier 2, and comparators 31 to 33, where the inputs of the filters 11 to 13 are respectively input The three-phase differential current signals i da , i db , i dco formed by the transformer longitudinal differential protection are the three-phase differential current instantaneous voltage drops caused by the current flowing through the three Wd in Figure 2. Value signal. The input of the filter 01 is input to the transformer Y. Side zero sequence current instantaneous value signal 3i. Its output terminal is connected to one input terminal of multiplier 2, the other input terminal of multiplier 2 inputs the setting value K, the negative input terminals of comparators 31 to 33 are connected to the output terminals of multiplier 2, and its positive input terminals are respectively Connected to the output terminals of the filters 11 ~ 13, the comparators 31 ~ 33 output the braking signals of phase A, B and C respectively. The braking signals are directly connected to the AND gate inputs of the differential parts of the comparison ratios, that is, they are connected from part A in Figure 1, and participate in the contrast ratio together with the inrush current and the reverse signal output from the over-excitation detection unit. The output signal of the braking unit is used for braking. When the positive input signal in the comparators 31 to 33 is less than the negative input signal, the comparator outputs 0 (low potential) and outputs the corresponding phase braking signal to brake the corresponding phase ratio differential protection to prevent the transformer differential protection. Misoperation; otherwise the comparator output 1 (high potential) allows the corresponding ratio differential protection action. In the case where the differential current and the zero-sequence current are all calculated to the same side and the same transformation ratio, the setting value K is 0.1. By applying the method and device of the present invention, Y can be completely avoided. The transformer differential protection caused by the external ground fault in the side area malfunctions without affecting the correct operation of the differential protection in the case of a fault in the area. Example 2:
图 4所示为实施零序制动的另一个实施例。该装置由滤波器 01、 02、 03、 滤波器 11〜13、 求最大值电路 4、 乘法器 2、 比较器 31〜33构成， 其中滤波器 01、 02、 03的输入端分别输入变压器各中性点接地侧（或分 支） 的零序电流瞬时值信号 3i1Q、 3i20 3i3Q， 其输出端分别与求最大值 电路 4 的输入端相连接，乘法器 2的一个输入端接求最大值电路 4的输 出端，其另一个输入端输入整定值 K, 比较器 31〜33的负输入端接乘法 器 2的输出端，滤波器 11〜13的输入端分别输入从变压器纵差保护中获 得的三相差动电流瞬时值信号 ida、 idb、 idc, 其输出端分别与比较器 31〜 33的正输入端相连接， 比较器 31〜33分别输出 A相、 B相、 C相制动 信号。当比较器 31〜33中的正输入端信号小于负输入端信号， 比较器输 出 0， 输出相应相制动信号， 对相应相比率差动保护进行制动， 防止变 压器纵差保护误动； 否则比较器输出 1， 允许相应相比率差动保护动作。 在差动电流与零序电流归算到同一侧、同一变比情况下，整定值 K为 0.1。 应用本发明方法装置， 可完全避免中性点接地侧区外接地故障导致的变 压器纵差保护误动， 且不影响区内故障情况下纵差保护的正确动作。 实施例 3 : Fig. 4 shows another embodiment for implementing zero sequence braking. The device is composed of filters 01, 02, 03, filters 11 to 13, a maximum value calculating circuit 4, a multiplier 2, and a comparator 31 to 33, wherein the input terminals of the filters 01, 02, and 03 are respectively input to each of the transformers. The zero-sequence current instantaneous value signals 3i 1Q and 3i 20 3i 3Q of the ground point (or branch) of the neutral point are connected to the input terminal of the maximum-calculation circuit 4 respectively, and one input terminal of the multiplier 2 is connected to the maximum value. The output of circuit 4 has the other input to set value K. The negative input of comparators 31 to 33 is connected to the output of multiplier 2. The inputs of filters 11 to 13 are input from the transformer differential protection. The instantaneous value signals of three-phase differential currents i da , i db , i dc are connected to the positive input terminals of comparators 31 to 33 respectively, and the comparators 31 to 33 respectively output the phases A, B, and C. Action signal. When the positive input signal in the comparators 31 ~ 33 is less than the negative input signal, the comparator outputs 0 and outputs the corresponding phase braking signal to brake the corresponding phase ratio differential protection to prevent the transformer differential protection from malfunctioning; otherwise Comparator output 1 allows corresponding ratio differential protection action. When the differential current and the zero-sequence current are reduced to the same side and the same transformation ratio, the setting value K is 0.1. By applying the method and device of the present invention, it is possible to completely avoid misoperation of the transformer differential protection caused by an external ground fault in the neutral side ground side zone, and it does not affect the correct operation of the longitudinal differential protection in the case of a zone fault. Example 3:
图 5所示为实施零序制动方法的又一个实施例。实施例装置由 滤波 器 01、 02、 03、 乘法器 41、 42、 43、 加法器 5、 乘法器 2、 滤波器 11〜 13、 比较器 31〜33构成， 其中滤波器 01、 02、 03的输入端分别输入变 压器各中性点接地侧 （或分支） 的零序电流瞬时值信号 3i1Q、 3i2。、 3i3Q， 其输出端分别与乘法器 41、 42、 43的一个输入端相连接， 乘法器 41、 42、 43的另一个输入端分别输入预先设定值 k1Q、 k2Q、 k3Q， 其输出端分 别与加法器 5的输入端相连接， 乘法器 2的一个输入端接加法器 5的输 出端，其另一个输入端输入整定值 K， 比较器 31〜33的负输入端分别接 乘法器 2的输出端，滤波器 11〜13的输入端分别输入变压器纵差保护中 的三相差动电流瞬时值信号 ida、 idb、 idc, 滤波器 11〜13的输出端分别与 比较器 31〜33的正输入端相连接，比较器 31〜33分别输出 A相、 B相、 C 相制动信号。 在差动电流与零序电流归算到同一侧、 同一变比及 k1() = 0.8、 k2o=0.6 、k3Q=0.3的情况下，整定值 K值为 0.1。当比较器 31〜 33中的正输入端信号小于负输入端信号， 比较器输出 0， 输出相应相制 动信号,对相应相比率差动保护进行制动， 防止变压器纵差保护误动； 否 则比较器输出 1， 允许相应相比率差动保护动作。应用本发明方法装置， 可完全避免中性点接地侧区外接地故障导致的变压器纵差保护误动， 且 不影响区内故障情况下纵差保护的正确动作。 FIG. 5 shows still another embodiment of the zero-sequence braking method. The device of the embodiment is composed of filters 01, 02, 03, multipliers 41, 42, 43, adder 5, multiplier 2, filters 11 to 13, and comparators 31 to 33, of which filters 01, 02, and 03 The input terminals input the instantaneous zero-sequence current signals 3i 1Q and 3i 2 of the neutral side (or branch) of each transformer. , 3i 3Q , whose output terminals are respectively connected to one input terminal of multipliers 41, 42, 43 and the other input terminals of multipliers 41, 42, 43 respectively input preset values k1Q , k2Q , k3Q , Its output terminal is connected to the input terminal of adder 5, one input terminal of multiplier 2 is connected to the output terminal of adder 5, the other input terminal is input to the setting value K, and the negative input terminals of comparators 31 to 33 are connected respectively. The output of multiplier 2 and the inputs of filters 11 to 13 respectively input the three-phase differential current signals i da , i db , i dc in the transformer longitudinal differential protection. The outputs of filters 11 to 13 are compared with The positive input terminals of the comparators 31 to 33 are connected to each other, and the comparators 31 to 33 output brake signals of phase A, phase B, and phase C, respectively. When the differential current and the zero-sequence current are calculated on the same side, the same transformation ratio, and k 1 () = 0.8, k 2 o = 0.6, and k 3Q = 0.3, the setting value K is 0.1. When the positive input signal in the comparators 31 to 33 is less than the negative input signal, the comparator outputs 0 and outputs the corresponding phase braking signal to brake the corresponding phase ratio differential protection to prevent the transformer differential protection from malfunctioning; otherwise Comparator output 1 allows corresponding ratio differential protection action. By applying the method and device of the present invention, it is possible to completely avoid misoperation of the transformer differential protection caused by an external ground fault in the neutral side ground side zone, and it does not affect the correct operation of the longitudinal differential protection in the case of a zone fault.

Claims

权利要求书 Claim
1、 一种用于变压器差动保护的零序电流制动方法， 其特征在于- 用变压器纵差保护中的一相差动电流与变压器 YQ侧零序电流构成该相 零序比率制动单元， 当比率值小于整定值 K时，输出该相制动信号,对相 应相比率差动保护进行制动; 零序制动依据以下关系- I dx 3 I。<K 1. A zero-sequence current braking method for transformer differential protection, characterized in that-a phase differential current in the transformer longitudinal differential protection and a zero-sequence current on the transformer Y Q side constitute the phase zero-sequence ratio braking unit When the ratio value is less than the setting value K, the phase braking signal is output to brake the corresponding phase ratio differential protection; the zero-sequence braking is based on the following relationship-I dx 3 I. <K
式中 I dx为变压器纵差保护差动电流 （ I da、 I db、 I do) 中的任意一相 差动电流， （31。） 为 Y。侧零序电流； In the formula, I dx is any phase differential current of the transformer differential protection differential current (I da , I db , I do), and (31.) is Y. Side zero sequence current
在零序电流与三相差动电流归算到同一侧的情况下，整定值 K的范 围为- In the case where the zero-sequence current and the three-phase differential current are reduced to the same side, the range of the setting value K is −
0<K <1/3。 0 <K <1/3.
2、 根据权利要求 1所述的用于变压器差动保护的零序电流制动方 法， 其特征在于： 当变压器存在多个 YQ侧时， 31。 的表达式为： 2. The zero-sequence current braking method for transformer differential protection according to claim 1, characterized in that, when there are multiple Y Q sides of the transformer, 31. The expression is:
31。= (3110、 3120、 31 ） max 31. = (31 10 , 31 20 , 31) max
式中 （311()、 3I2。、 ······ 3Ino)为各 Yo侧的零序电流， （311()、 3120、 ……、In the formula (31 1 () , 3I 2 ..., 3I no ) is the zero-sequence current of each Yo side, (31 1 () , 31 20 , ...,
3Ino) max为各 YQ侧的零序电流中的最大值。 3I no ) max is the maximum value of the zero-sequence current on each Y Q side.
3、 根据权利要求 1所述的用于变压器差动保护的零序电流制动方 法， 其特征在于： 当变压器存在多个 Yc侧时， 31。 的表达式为：  3. The zero-sequence current braking method for transformer differential protection according to claim 1, characterized in that: when there are multiple Yc sides of the transformer, 31. The expression is:
3 I。=3I10Xk10+3I20Xk20+ …… +3InoXkn0 3 I. = 3I 10 Xk 10 + 3I 20 Xk 20 + …… + 3I no Xk n0
式中 （3I1()、 3I2。、 …… 3In。） 为各 YQ侧的零序电流， （k1()、 k2。 、 ······ kn0) 为预先设定的权值， （3I1()Xk1。+3I2()Xk2()+ ······ +3InoXkn0) 为各In the formula (3I 1 () , 3I 2 ... 3I n .) Is the zero-sequence current of each Y Q side, and (k 1 () , k 2 .... K n0 ) is preset Fixed weight, (3I 1 () Xk 1. + 3I 2 () Xk 2 () + ····· + 3I no Xk n0 ) are each
Yo侧的零序电流的加权求和值， 当零序电流与三相差动电流归算到同一 侧及权值在 0< (k1()、 k2。 、 …… knQ) 1的情况下， 整定值 K为 0<K <1/3。 The weighted sum of the zero-sequence current on the Yo side, when the zero-sequence current and the three-phase differential current are reduced to the same side and the weight is 0 <(k 1 () , k 2 ... K nQ ) 1 In this case, the setting value K is 0 <K <1/3.
PCT/CN2005/000194 2004-02-13 2005-02-16 A zero-sequence current braking method for power transformer differential protection WO2005078886A1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
CNB2004100163128A CN100413169C (en) 2004-02-13 2004-02-13 Phase-splitting zero-sequence brake method for preventing multiple-branch voltage transformer differential protection unwanted operation
CNB2004100163113A CN100367600C (en) 2004-02-13 2004-02-13 Phase-splitting integrated zero-sequence brake method for preventing multiple-branch voltage transformer differential protection unwanted operation
CN200410016305.8 2004-02-13
CNB2004100163058A CN100388581C (en) 2004-02-13 2004-02-13 Phase-splitting differential flow method for preventing voltage transformer differential protection unwanted operation
CN200410016312.8 2004-02-13
CN200410016311.3 2004-02-13

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CN104701813A (en) * 2015-03-13 2015-06-10 国家电网公司 Phase compensating method for longitudinal differential protective current of YNd5 wired transformer
RU2597243C1 (en) * 2015-09-01 2016-09-10 Федеральное государственное автономное образовательное учреждение высшего образования "Национальный исследовательский Томский политехнический университет" Method of arrangement and adjustment of phase differential relay protection
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CN113270856B (en) * 2021-05-07 2022-07-26 国网河南省电力公司电力科学研究院 Circuit pilot differential protection method for synchronization based on current zero crossing point
CN113488964A (en) * 2021-07-27 2021-10-08 西安热工研究院有限公司 System and method for protecting high-speed permanent magnet wind driven generator and outgoing cable by electric quantity
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