CN103545798A - A Distance Protection Method for Fail-Open Components in Oscillating Blocking - Google Patents

Abstract

The invention relates to a distance protection method for a fault-opening element in oscillation locking, comprising the following steps: collecting three-phase current and three-phase voltage at the installation place of the protection; judging whether to enter the oscillation locking state; if

and

Go to the penultimate step, otherwise, go to the next step; if the current asymmetry m≥0.65, open the distance protection; otherwise, go to the next step; if the oscillation center voltage

Either one satisfies Delay 200ms to open the distance protection section I, and open the distance protection section II instantaneously; otherwise, go to the next step; if

Either one satisfies

Delay 200ms to open distance protection stage I, and instantaneously open distance protection stage II; otherwise, block distance protection; if Either one satisfies , open the distance protection with a delay of 150ms; otherwise, go to the next step; if

Either one satisfies

, delay 150ms to open the distance protection; otherwise, block the distance protection. The method improves the sensitivity of the fault-opening element in the oscillation blocking, so that the distance protection can operate correctly when the fault passes through a relatively large transition resistance.

Description

A Distance Protection Method for Fail-Open Components in Oscillating Blocking

technical field

The invention relates to a protection method in the field of relay protection of electric power systems, in particular to a distance protection method for fault open components in oscillation blocking.

Background technique

Distance protection is widely used in power systems of different voltage levels as backup protection of transmission lines and transformers.

When the power system oscillates, the measurement impedance changes periodically, and there is a possibility of misoperation of the distance protection. For the distance protection sections I and II, due to the short action time, the microcomputer protection device adopts an oscillation blocking element to prevent the distance protection sections I and II from oscillating. Malfunction during the process, for the distance protection section III, because the action time is long, rely on the action delay to avoid the oscillation, if a fault occurs during the oscillation blocking process, use the fault open element in the oscillation blocking to open the distance protection sections I and II, Fail-open elements are divided into asymmetric fail-open elements and symmetric fail-open elements.

作为对称故障开放元件。对于不对称故障开放元件，当线路处于重负荷运行时，发生经大过渡电阻接地故障时，电流不对称度m不满足条件，无法开放距离保护，造成保护无法正确动作。对于对称故障开放元件，振荡中心电压

一般采取两段式，二者之间存在重叠动作区，开放时间不一致，当发生三相经过渡电阻短路时，开放时间较长，影响保护的快速性。The current asymmetry m is commonly used as an asymmetric fault opening element, and the oscillation center voltage is used

As a symmetrical fail-open element. For asymmetric fault open components, when the line is under heavy load operation, when a ground fault occurs through a large transition resistance, the current asymmetry m does not meet the conditions, and the distance protection cannot be opened, resulting in the protection not being able to operate correctly. For symmetrical fail-open elements, the oscillating center voltage

Generally, two stages are adopted, and there are overlapping action areas between the two, and the opening time is inconsistent. When a three-phase short circuit occurs through the transition resistance, the opening time is longer, which affects the rapidity of protection.

To sum up, the existing fault-opening components in oscillation blocking have low sensitivity when dealing with heavy-load faults through large transition resistance and three-phase transition resistance faults. In serious cases, the distance protection cannot be opened, resulting in protection failure.

Contents of the invention

Aiming at the deficiencies in the prior art, the object of the present invention is to provide a distance protection method for fault-opening elements in oscillation blocking, which improves the sensitivity of fault-opening elements in oscillation blocking, so that distance protection can Act right.

The object of the present invention is to adopt following technical scheme to realize:

The present invention provides a distance protection method for fault-opening elements in oscillation locking, the improvement of which is that the method includes the following steps:

(1) Collect the three-phase current and three-phase voltage at the protection installation;

(2) Judging whether to enter the oscillation locking state;

相为基准的负序电流的绝对值小于负序电流定值

且

相为基准的零序电流的绝对值小于零序电流定值

转至步骤（7），否则，转至步骤（4）；(3) If

The absolute value of the negative sequence current based on the phase is less than the negative sequence current setting value

and

The absolute value of the phase-based zero-sequence current is less than the zero-sequence current setting

Go to step (7), otherwise, go to step (4);

(4) If the current asymmetry m≥0.65, enable distance protection; otherwise, go to step (5);

延时200ms开放距离保护I段，瞬时开放距离保护II段；否则，转至步骤（6）；(5) If the oscillation center voltage Either one satisfies

Delay 200ms to open distance protection section I, and instantly open distance protection section II; otherwise, go to step (6);

中任一满足

延时200ms开放距离保护I段，瞬时开放距离保护II段；若m＜0.65，且

都满足

闭锁距离保护；(6) If the oscillation center voltage

Either one satisfies

Delay 200ms to open distance protection section I, and instantaneous open distance protection section II; if m<0.65, and

all satisfied

Blocking distance protection;

中任一满足

时，延时150ms开放距离保护；否则，转至步骤（8）；(7) If the oscillation center voltage

Either one satisfies

, open the distance protection with a delay of 150ms; otherwise, go to step (8);

都满足闭锁距离保护。(8) If the oscillation center voltage Either one satisfies , delay 150ms to open the distance protection; if

all satisfied Blocking distance protection.

和

三相电压分别为

和

Further, in the step (1), the three-phase currents at the protection installation are respectively

and

The three-phase voltages are

and

相为基准的正序电流

相为基准的负序电流

相为基准的零序电流

电流不对称度m和振荡中心电压

分别为A、B、C。Further, in the step (2), if the distance protection does not enter the oscillation lock, directly open the distance protection, if the distance protection enters the oscillation lock, calculate

Phase-based positive sequence current

Negative sequence current based on phase

Phase-based zero-sequence current

Current asymmetry m and oscillation center voltage

They are A, B, and C respectively.

所述振荡中心电压

中的i分别为A、B、C、AB、BC和CA；Further, the current asymmetry

The oscillation center voltage

i in are A, B, C, AB, BC and CA respectively;

中的U_i分别为U_A、U_B、U_C、U_AB、U_BC和U_CA，分别用下述表达式表示： $U_A=\left|{\stackrel{\&CenterDot;}{U}}_A\right|,U_B=\left|{\stackrel{\&CenterDot;}{U}}_B\right|,U_C=\left|{\stackrel{\&CenterDot;}{U}}_C\right|,U_{\mathrm{AB}}=|{\stackrel{\&CenterDot;}{U}}_A-{\stackrel{\&CenterDot;}{U}}_B|,U_{\mathrm{BC}}=|{\stackrel{\&CenterDot;}{U}}_B-{\stackrel{\&CenterDot;}{U}}_C|$ 和 $U_{\mathrm{CA}}=|{\stackrel{\&CenterDot;}{U}}_C-{\stackrel{\&CenterDot;}{U}}_A|;$ The oscillation center voltage

U _i in is U _A , U _B , U _C , U _AB , U _BC and U _CA , expressed by the following expressions: $u_A=\left|{\stackrel{\&Center\; Dot;}{u}}_A\right|,u_B=\left|{\stackrel{\&Center\; Dot;}{u}}_B\right|,u_C=\left|{\stackrel{\&Center\; Dot;}{u}}_C\right|,u_{\mathrm{AB}}=|{\stackrel{\&Center\; Dot;}{u}}_A-{\stackrel{\&CenterDot;}{u}}_B|,u_{\mathrm{BC}}=|{\stackrel{\&CenterDot;}{u}}_B-{\stackrel{\&CenterDot;}{u}}_C|$ and $u_{\mathrm{CA}}=|{\stackrel{\&Center\; Dot;}{u}}_C-{\stackrel{\&Center\; Dot;}{u}}_A|;$

中的

分别为

分别用下述表达式表示：

为线路阻抗角；The oscillation center voltage

middle

respectively

Expressed by the following expressions:

is the line impedance angle;

的单位是标幺值，其基准值分别为相电压或线电压的有效值。

The unit of is per unit value, and its reference value is the effective value of phase voltage or line voltage respectively.

Further, in the step (3), wherein I _2.set is the negative sequence current fixed value, which is used to judge whether the fault is an asymmetric fault; I _0.set is the zero sequence current fixed value, which is used to judge whether the fault is Ground Fault.

与

二者之一，同时m≥0.65即判断为线路发生不对称故障。Further, in the step (4), satisfy

and

One of the two, and at the same time m≥0.65, it is judged that the line has an asymmetrical fault.

与

二者之一，且m＜0.65，且

中任一满足延时200ms开放距离保护I段，瞬时开放距离保护II段；Further, in the step (5), satisfy

and

One of the two, and m<0.65, and

Either one satisfies Delay 200ms to open distance protection section I, and instantaneous open distance protection section II;

表示为：满足下述表达式

和

的任意一个；其中pu表示标幺值。either meet

Expressed as: satisfy the following expression

and

Any one of ; where pu represents the per unit value.

与

二者之一，且m＜0.65，且

中任一满足

延时200ms开放距离保护I段，瞬时开放距离保护II段；Further, in the step (6), satisfy

and

One of the two, and m<0.65, and

Either one satisfies

Delay 200ms to open distance protection section I, and instantaneous open distance protection section II;

表示为：满足下述表达式

和

中的任意一个；Either of the

Expressed as: satisfy the following expression

and

any of the

表示为：

和表达式全部满足；All the above are satisfied

Expressed as:

and All expressions are satisfied;

Where pu represents the per unit value.

表示为：满足

和

中的任意一个；其中pu表示标幺值。Further, in the step (7), any one that satisfies

Expressed as: satisfied

and

Any one of them; where pu represents the per unit value.

和

中的任意一个；Further, in the step (8), any of the Expressed as:

and

any of the

表示为：

和

全部满足；All the above are satisfied

Expressed as:

and

all satisfied;

Where pu represents the per unit value.

Compared with prior art, the beneficial effect that the present invention reaches is:

互相配合，m开放严重不对称故障，

开放轻微不对称故障，使距离保护在经较大过渡电阻故障时能够正确开放，提高距离保护的耐过渡能力。The distance protection method of the fault-opening element in the oscillation blocking provided by the present invention redesigns the symmetrical fault-opening area by improving the symmetrical fault-opening condition, reduces the protection opening delay in the case of a symmetrical fault, and improves the protection of the symmetrical fault-opening element in the oscillation blocking Sensitivity, which is beneficial to quickly remove three-phase short-circuit faults and ensure stable operation of the system. For asymmetric fault-opening components, use current asymmetry m and oscillation center voltage

cooperate with each other, m open severe asymmetric faults,

Open slightly asymmetrical faults, so that the distance protection can be opened correctly when a large transition resistance fault occurs, and improve the transition resistance of the distance protection.

Description of drawings

Fig. 1 is a flowchart of a distance protection method for a fault-open element in oscillation blocking provided by the present invention.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Install protection devices on the power system lines. The functions include main protection and backup protection. For 110kV and above voltage level line protection, distance protection is used as backup protection. Distance protection is affected by system oscillation, and it is necessary to adopt oscillation blocking for distance protection sections I and II Measures, in order to deal with the failure of the fault distance protection during the oscillation locking period, it is necessary to configure the oscillation locking opening element. The oscillation locking opening element is divided into a symmetrical fault opening element and an asymmetrical fault opening element. The present invention improves the opening element in the oscillation locking, To improve the action performance of distance protection when a fault occurs during oscillation blocking, a distance protection method for fault-open elements in oscillation blocking is provided.

The flow chart of this method is shown in Figure 1, comprises the following steps:

和

三相电压分别为

和 (1) Collect the three-phase current and three-phase voltage at the place where the protection is installed: the three-phase currents are respectively

and

The three-phase voltages are

and

(2) Judging whether to enter the oscillation locking state:

A相为基准的负序电流

A相为基准的零序电流

电流不对称度m和振荡中心电压

If the distance protection does not enter oscillation blocking, open the distance protection directly; if the distance protection enters oscillation blocking, take phase A as an example, calculate the positive sequence current based on phase A

Negative sequence current based on phase A

Zero-sequence current based on phase A

Current asymmetry m and oscillation center voltage

所述振荡中心电压

中的i分别为A、B、C、AB、BC和CA；The current asymmetry

The oscillation center voltage

i in are A, B, C, AB, BC and CA respectively;

中的U_i分别为U_A、U_B、U_C、U_AB、U_BC和U_CA，分别用下述表达式表示： $U_A=\left|{\stackrel{\&CenterDot;}{U}}_A\right|,U_B=\left|{\stackrel{\&CenterDot;}{U}}_B\right|,U_C=\left|{\stackrel{\&CenterDot;}{U}}_C\right|,U_{\mathrm{AB}}=|{\stackrel{\&CenterDot;}{U}}_A-{\stackrel{\&CenterDot;}{U}}_B|,U_{\mathrm{BC}}=|{\stackrel{\&CenterDot;}{U}}_B-{\stackrel{\&CenterDot;}{U}}_C|$ 和 $U_{\mathrm{CA}}=|{\stackrel{\&CenterDot;}{U}}_C-{\stackrel{\&CenterDot;}{U}}_A|;$ The oscillation center voltage

U _i in is U _A , U _B , U _C , U _AB , U _BC and U _CA , expressed by the following expressions: $u_A=\left|{\stackrel{\&Center\; Dot;}{u}}_A\right|,u_B=\left|{\stackrel{\&Center\; Dot;}{u}}_B\right|,u_C=\left|{\stackrel{\&Center\; Dot;}{u}}_C\right|,u_{\mathrm{AB}}=|{\stackrel{\&Center\; Dot;}{u}}_A-{\stackrel{\&CenterDot;}{u}}_B|,u_{\mathrm{BC}}=|{\stackrel{\&CenterDot;}{u}}_B-{\stackrel{\&Center\; Dot;}{u}}_C|$ and $u_{\mathrm{CA}}=|{\stackrel{\&CenterDot;}{u}}_C-{\stackrel{\&CenterDot;}{u}}_A|;$

中的

分别为

分别用下述表达式表示：

为线路阻抗角。The oscillation center voltage

middle

respectively

Expressed by the following expressions:

is the line impedance angle.

且A相为基准的零序电流的绝对值小于零序电流定值

转至步骤（7），否则，转至步骤（4）；其中I_2.set为负序电流定值，用于判断故障是否为不对称故障；I_0.set为零序电流定值，用于判断故障是否为接地故障。(3) If the absolute value of the negative sequence current based on phase A is less than the negative sequence current fixed value

And the absolute value of the zero-sequence current based on phase A is less than the zero-sequence current setting

Go to step (7), otherwise, go to step (4); where I _2.set is the negative-sequence current setting, used to judge whether the fault is an asymmetrical fault; I _0.set is the zero-sequence current setting, use It is used to judge whether the fault is a ground fault.

二者之一，同时m≥0.65即判断为线路发生不对称故障。(4) If the current asymmetry m≥0.65, open the distance protection; otherwise, go to step (5); satisfy and

One of the two, and at the same time m≥0.65, it is judged that the line has an asymmetrical fault.

与

二者之一，且m＜0.65，且中任一满足延时200ms开放距离保护I段，瞬时开放距离保护II段；否则，转至步骤（6）；(5) meet

and

One of the two, and m<0.65, and Either one satisfies Delay 200ms to open distance protection section I, and instantly open distance protection section II; otherwise, go to step (6);

表示为：满足下述表达式

和

的任意一个；其中pu表示标幺值。；either meet

Expressed as: satisfy the following expression

and

Any one of ; where pu represents the per unit value. ;

表示为：满足下述表达式

和

的任意一个；其中pu表示标幺值。either meet

Expressed as: satisfy the following expression

and

Any one of ; where pu represents the per unit value.

二者之一，且m＜0.65，且

中任一满足

延时200ms开放距离保护I段，瞬时开放距离保护II段；(6) meet and

One of the two, and m<0.65, and

Either one satisfies

Delay 200ms to open distance protection section I, and instantaneous open distance protection section II;

都满足闭锁距离保护；If m<0.65, and

all satisfied Blocking distance protection;

表示为：满足下述表达式

和中的任意一个；Either of the

Expressed as: satisfy the following expression

and any of the

表示为：

和

表达式全部满足；其中pu表示标幺值。All the above are satisfied

Expressed as:

and

The expressions are all satisfied; where pu represents the per unit value.

且

且振荡中心电压

中任一满足时，延时150ms开放距离保护；否则，转至步骤（8）；(7) If

and

And the oscillation center voltage

Either one satisfies , open the distance protection with a delay of 150ms; otherwise, go to step (8);

表示为：满足

和

中的任意一个；其中pu表示标幺值。either meet

Expressed as: satisfied

and

Any one of them; where pu represents the per unit value.

且振荡中心电压中任一满足时，延时150ms开放距离保护；若

都满足

闭锁距离保护；(8) If and

And the oscillation center voltage Either one satisfies , delay 150ms to open the distance protection; if

all satisfied

Blocking distance protection;

表示为：

和

中的任意一个；either meet

Expressed as:

and

any of the

表示为：

和

全部满足；All the above are satisfied

Expressed as:

and

all satisfied;

Where pu represents the per unit value.

开放轻微不不对称故障，使距离保护在经较大过渡电阻故障时能够正确开放，提高距离保护的耐过渡能力。The distance protection method of the fault-opening element in the oscillation blocking provided by the present invention redesigns the symmetrical fault-opening area by improving the symmetrical fault-opening condition, reduces the protection opening delay in the case of a symmetrical fault, and improves the protection of the symmetrical fault-opening element in the oscillation blocking Sensitivity, which is beneficial to quickly remove three-phase short-circuit faults and ensure stable operation of the system. For asymmetric fault-opening components, use current asymmetry m and oscillation center voltage cooperate with each other, m open severe asymmetric faults,

The opening of slightly asymmetrical faults enables the distance protection to be opened correctly when a large transition resistance fault occurs, and improves the transition resistance of the distance protection.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims (10)

1. a distance protecting method for fault opening element in out-of-step blocking, is characterized in that, described method comprises the steps:

(1) gather protection installation place three-phase current and three-phase voltage;

(2) judge whether to enter out-of-step blocking state;

(3) if

the absolute value that is mutually the negative-sequence current of benchmark is less than negative-sequence current definite value and

the absolute value that is mutually the zero-sequence current of benchmark is less than zero-sequence current definite value

go to step (7), otherwise, go to step (4);

(4) if current asymmetry degree m >=0.65, open distance protection; Otherwise, go to step (5);

(5) if voltage of oscillation center

in arbitraryly meet

time delay 200ms open distance protection I section, instantaneous open distance protection II section; Otherwise, go to step (6);

(6) if voltage of oscillation center in arbitraryly meet

time delay 200ms open distance protection I section, instantaneous open distance protection II section; If m < 0.65, and

all meet

locking distance protection;

(7) if voltage of oscillation center

in arbitraryly meet time, the protection of time delay 150ms open distance; Otherwise, go to step (8);

(8) if voltage of oscillation center

in arbitraryly meet

time, the protection of time delay 150ms open distance; If

all meet

locking distance protection.

2. distance protecting method as claimed in claim 1, is characterized in that, in described step (1), protection installation place three-phase current is respectively

with

three-phase voltage is respectively

with

3. distance protecting method as claimed in claim 1, is characterized in that, in described step (2), if distance protection does not enter out-of-step blocking, directly open distance protection, if distance protection enters out-of-step blocking, calculates be the forward-order current of benchmark mutually

be the negative-sequence current of benchmark mutually

be the zero-sequence current of benchmark mutually

current asymmetry degree m and voltage of oscillation center

be respectively A, B, C.

4. distance protecting method as claimed in claim 3, is characterized in that, described current asymmetry degree

described voltage of oscillation center

in i be respectively A, B, C, AB, BC and CA;

Described voltage of oscillation center

in Ui be respectively U _a, U _b, U _c, U _aB, U _bCand U _cA, by following expression formula, represent respectively: $U_A=\left|{\stackrel{\&CenterDot;}{U}}_A\right|,U_B=\left|{\stackrel{\&CenterDot;}{U}}_B\right|,U_C=\left|{\stackrel{\&CenterDot;}{U}}_C\right|,U_{\mathrm{AB}}=|{\stackrel{\&CenterDot;}{U}}_A-{\stackrel{\&CenterDot;}{U}}_B|,U_{\mathrm{BC}}=|{\stackrel{\&CenterDot;}{U}}_B-{\stackrel{\&CenterDot;}{U}}_C|$ With $U_{\mathrm{CA}}=|{\stackrel{\&CenterDot;}{U}}_C-{\stackrel{\&CenterDot;}{U}}_A|;$

Described voltage of oscillation center in

be respectively

by following expression formula, represent respectively:

for line impedance angle;

unit be perunit value, its fiducial value is respectively the effective value of phase voltage or line voltage.

5. distance protecting method as claimed in claim 1, is characterized in that, in described step (3), and I wherein _2.setfor negative-sequence current definite value, for failure judgement, whether be unbalanced fault; I _0.setfor zero-sequence current definite value, for failure judgement, whether be earth fault.

6. distance protecting method as claimed in claim 1, is characterized in that, in described step (4), meets

with

one of the two, m>=0.65 is judged as circuit generation unbalanced fault simultaneously.

7. distance protecting method as claimed in claim 1, is characterized in that, in described step (5), meets

with

one of the two, and m < 0.65, and in arbitraryly meet

time delay 200ms open distance protection I section, instantaneous open distance protection II section;

Arbitrary satisfied

be expressed as: meet following expression formula

with

any one; Wherein pu represents perunit value.

8. distance protecting method as claimed in claim 1, is characterized in that, in described step (6), meets

with

one of the two, and m < 0.65, and

in arbitraryly meet

time delay 200ms open distance protection I section, instantaneous open distance protection II section;

Described arbitrary satisfied

be expressed as: meet following expression formula

with

in any one;

Describedly all meet

be expressed as:

with

expression formula all meets;

Wherein pu represents perunit value.

9. distance protecting method as claimed in claim 1, is characterized in that, in described step (7), arbitrary satisfied

be expressed as: meet

with

in any one; Wherein pu represents perunit value.

10. distance protecting method as claimed in claim 1, is characterized in that, in described step (8), arbitrary satisfied

be expressed as:

with

in any one;

Describedly all meet

be expressed as:

with

all meet;

Wherein pu represents perunit value.

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