CN105527543A - A method and device for judging the zero-sequence direction of a longitudinal connection of a high-voltage line - Google Patents

Abstract

The invention provides a method and a device for judging the longitudinal zero sequence direction of a high-voltage line, comprising the following steps: determining a first relative angle difference between zero sequence current at one side of a high-voltage line and a certain phase voltage; determining a second phase angle difference between the zero sequence current on the other side of the high-voltage line and the same phase voltage; if the difference value of the first relative angle difference and the second relative angle difference is within the preset angle difference range, the longitudinal zero sequence direction is a positive direction; otherwise, the longitudinal zero sequence direction is the reverse direction. When one phase voltage is subjected to PT disconnection, the method can be used for judging by using other phase voltages, so that the problem of locking zero sequence direction protection when non-three-phase PT disconnection occurs is avoided; when the high-resistance fault occurs, the problem of incorrect action of the zero-sequence directional element caused by small zero-sequence voltage and insufficient sensitivity is avoided; the problem of malfunction of zero sequence direction protection caused by the influence of zero sequence mutual inductance of a fault line on a non-fault line in the same-pole weak current and strong magnetic contact is solved.

Description

A method and device for judging the zero-sequence direction of a longitudinal connection of a high-voltage line

technical field

The invention relates to the technical field of electric power system relay protection, in particular to a method and device for judging the zero-sequence direction of a high-voltage line longitudinal connection.

Background technique

At present, the longitudinal zero-sequence directional protection of high-voltage lines is mainly used to protect single-phase high-resistance grounding faults. When the leading zero-sequence voltage direction is 90°, the longitudinal zero-sequence direction is considered to be the positive direction, and the longitudinal zero-sequence protection can operate. The use of zero-sequence directional elements for longitudinal zero-sequence directional protection has the characteristics of high sensitivity, but there are also the following problems:

Generally, when a PT (Potential Transforme, voltage transformer) secondary circuit disconnection fault occurs in the protection device, the longitudinal zero-sequence protection will be blocked, and when a high-impedance fault occurs in the area, the longitudinal zero-sequence protection will refuse to operate;

When a high-resistance grounding fault occurs at the near end of the high-voltage line, the amplitude of the zero-sequence voltage collected by the remote protection may be relatively low. refuse to move;

In addition, when the high-voltage lines on the same pole have the characteristics of weak current and strong magnetic connection, when a grounding asymmetric fault occurs on one high-voltage line, the other high-voltage line will be affected by the zero-sequence mutual inductance between the high-voltage lines, resulting in a fault on both sides of the healthy high-voltage line. The zero-sequence current meets the characteristics of leading the zero-sequence voltage direction of each side by 90°, which leads to the misoperation of the longitudinal zero-sequence protection.

Contents of the invention

The embodiment of the present invention provides a method for judging the zero-sequence direction of the longitudinal connection of high-voltage lines, which can solve the problems in the prior art by comparing the relative angle difference between the zero-sequence current on both sides of the high-voltage line and the voltage of the same phase in the three-phase voltage. There are technical problems in using the phase comparison results of the zero-sequence voltage and zero-sequence current on one side of the high-voltage line to judge. The method includes:

Determining the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages;

determining a second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one phase voltage of the three-phase voltage;

If the difference between the first relative angle difference and the second relative angle difference is within the preset angle difference range, the longitudinal zero-sequence direction is the positive direction; otherwise, the longitudinal zero-sequence direction is the reverse direction;

Wherein, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage.

In one embodiment, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage, including:

If the A-phase voltage is greater than 30V, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the A-phase voltage;

If the voltage of phase A is less than 30V and the voltage of phase B is greater than 30V, the voltage of one phase of the three-phase voltage on one side of the high-voltage line and the voltage of one phase of the three-phase voltage on the other side of the high-voltage line is the voltage of phase B;

If the B-phase voltage is less than 30V and the C-phase voltage is greater than 30V, then one of the three-phase voltages on one side of the high-voltage line and one of the three-phase voltages on the other side of the high-voltage line is the C-phase voltage.

In one embodiment, also includes:

If the C-phase voltage is less than 30V, then determine the longitudinal zero-sequence direction is the opposite direction.

In one embodiment, the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages is determined according to the following formula:

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

The second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one of the three-phase voltages is determined according to the following formula:

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

Among them, X is the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages; Y is the first relative angle difference between the zero-sequence current on the other side of the high-voltage line and one of the three-phase voltages Two relative angle differences; I _o is the zero-sequence current, is any phase voltage in the three-phase voltage; when , X=Y=-1.

In one embodiment, the preset angle difference range is (-60°, 60°).

In one embodiment, if the difference between the first relative angle difference and the second relative angle difference is within the preset angle difference range, the longitudinal zero-sequence direction is the positive direction; otherwise, the longitudinal zero-sequence direction is the reverse direction ,include:

When X _A >-1 and Y _A >-1, if -60°<X _A -Y _A <60°, the longitudinal zero-sequence direction is the positive direction; otherwise, the longitudinal zero-sequence direction is the reverse direction;

When X _A ＝-1 or Y _A ＝-1, X _B >-1 and Y _B >-1, if -60°<X _B -Y _B <60°, the longitudinal zero-sequence direction is the positive direction; Otherwise, the longitudinal zero-sequence direction is the opposite direction;

When X _B ＝-1 or Y _B ＝-1, X _C >-1 and Y _C >-1, if -60°<X _C -Y _C <60°, the longitudinal zero-sequence direction is the positive direction; Otherwise, the longitudinal zero-sequence direction is the opposite direction;

Among them, X _A , X _B , and X _C are the relative angle differences between the zero-sequence current on one side of the high-voltage line and the voltages of phase A, phase B, and phase C;

Y _A , Y _B , and Y _C are the relative angle differences between the zero-sequence current on the other side of the high-voltage line and the voltages of phase A, phase B, and phase C, respectively.

The embodiment of the present invention also provides a high-voltage line longitudinal zero-sequence direction discrimination device, which can solve the problem of the existing technology by comparing the relative angle difference between the zero-sequence current on both sides of the high-voltage line and the same phase voltage among the three-phase voltages. In the paper, there are technical problems in the identification of the phase comparison results of the zero-sequence voltage and zero-sequence current on one side of the high-voltage line. The unit includes:

The first relative angle difference determination module is used to determine the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one phase voltage of the three-phase voltage;

The second relative angle difference determination module is used to determine the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one phase voltage of the three-phase voltage;

The longitudinal zero-sequence direction determination module is used to determine the longitudinal zero-sequence direction if the difference between the first relative angle difference and the second relative angle difference is within the preset angle difference range; otherwise, the longitudinal zero-sequence direction is opposite direction;

Wherein, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage.

In one embodiment, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage, including:

If the A-phase voltage is greater than 30V, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the A-phase voltage;

If the voltage of phase A is less than 30V and the voltage of phase B is greater than 30V, the voltage of one phase of the three-phase voltage on one side of the high-voltage line and the voltage of one phase of the three-phase voltage on the other side of the high-voltage line is the voltage of phase B;

If the B-phase voltage is less than 30V and the C-phase voltage is greater than 30V, then one of the three-phase voltages on one side of the high-voltage line and one of the three-phase voltages on the other side of the high-voltage line is the C-phase voltage.

In one embodiment, also includes:

If the C-phase voltage is less than 30V, then determine the longitudinal zero-sequence direction is the opposite direction.

In one embodiment, the first relative angle difference determining module is specifically used for:

Determine the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one phase voltage of the three-phase voltage according to the following formula:

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

The second relative angle difference determination module is specifically used for:

Determine the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one phase voltage of the three-phase voltage according to the following formula:

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

Among them, X is the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages; Y is the first relative angle difference between the zero-sequence current on the other side of the high-voltage line and one of the three-phase voltages Two relative angle differences; I _o is the zero-sequence current, is any phase voltage in the three-phase voltage; when , X=Y=-1.

In one embodiment, the preset angle difference range is (-60°, 60°).

In one embodiment, the longitudinal zero-sequence direction determining module is specifically used for:

When X _A >-1 and Y _A >-1, if -60°<X _A -Y _A <60°, the longitudinal zero-sequence direction is the positive direction; otherwise, the longitudinal zero-sequence direction is the reverse direction;

When X _A ＝-1 or Y _A ＝-1, X _B >-1 and Y _B >-1, if -60°<X _B -Y _B <60°, the longitudinal zero-sequence direction is the positive direction; Otherwise, the longitudinal zero-sequence direction is the opposite direction;

When X _B ＝-1 or Y _B ＝-1, X _C >-1 and Y _C >-1, if -60°<X _C -Y _C <60°, the longitudinal zero-sequence direction is the positive direction; Otherwise, the longitudinal zero-sequence direction is the opposite direction;

Among them, X _A , X _B , and X _C are the relative angle differences between the zero-sequence current on one side of the high-voltage line and the voltages of phase A, phase B, and phase C;

Y _A , Y _B , and Y _C are the relative angle differences between the zero-sequence current on the other side of the high-voltage line and the voltages of phase A, phase B, and phase C, respectively.

In the embodiment of the present invention, the present invention uses the first relative angle difference between the zero-sequence current on one side of the high-voltage line and a certain phase voltage, and the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and the same phase voltage Make a comparison to judge whether the longitudinal zero-sequence direction is forward or reverse. When one of the phase voltages has a PT disconnection, it can also use other phase voltages to continue to judge, so it can avoid blocking zero when non-three-phase PT disconnection occurs. sequence direction protection problem; in the case of high-resistance faults, the use of phase voltage discrimination can also avoid the problem of incorrect action of zero-sequence directional elements caused by the small zero-sequence voltage and insufficient sensitivity; the key of the present invention is to adopt the corresponding phase voltage and The phase difference of the zero-sequence current is compared to determine the zero-sequence direction, which fundamentally solves the problem of zero-sequence direction protection misoperation caused by the influence of the zero-sequence mutual inductance of the faulty line on non-fault lines connected with weak current and strong magnetism on the same pole.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a flow chart of a method for judging the zero-sequence direction of a vertical connection of a high-voltage line provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the direction of the zero-sequence current on both sides of a phase A fault in the high-voltage line area provided by the embodiment of the present invention;

Fig. 3 is a schematic diagram of the direction of the zero-sequence current on both sides of a high-voltage line N-side rear area A-phase fault provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of the direction of the zero-sequence current on both sides of a phase A fault in the rear area of the high-voltage line M side provided by an embodiment of the present invention;

Fig. 5 is a structural diagram of a high-voltage line longitudinal zero-sequence direction discrimination device provided by an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The existing longitudinal zero-sequence directional protection for high-voltage and extra-high-voltage lines in power systems is used to protect single-phase high-resistance grounding faults in the power system. However, this method is susceptible to insufficient zero-sequence voltage sensitivity, PT disconnection, and the conventional zero-sequence direction misjudgment in the case of weak current and strong magnetic connection on the same pole line will lead to protection misoperation.

In view of the problems existing in the above-mentioned prior art, the present invention proposes a method for judging the zero-sequence direction of the longitudinal connection of high-voltage lines. The method is based on the transmission of relevant information based on the fiber optic channel of the line longitudinal connection, and the protection devices on both sides of the line can transmit analog values through the fiber optic channel. The relative phase relationship between the zero-sequence current and the phase voltage on this side is transmitted to the opposite side, and then combined with the results of the relative phase relationship on the opposite side to comprehensively determine the fault direction.

Specifically, the process flow of the method for determining the zero-sequence direction of the longitudinal connection of high-voltage lines is shown in Figure 1. The method includes:

Step 101: Determine the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages;

Step 102: Determine the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one phase voltage of the three-phase voltage;

Step 103: If the difference between the first relative angle difference and the second relative angle difference is within the preset angle difference range, then the longitudinal zero-sequence direction is the positive direction, and the longitudinal zero-sequence protection can be activated; otherwise, the longitudinal zero-sequence direction In the opposite direction, the longitudinal zero-sequence protection does not operate;

Wherein, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage.

During specific implementation, it is necessary to transmit the first relative angle difference on one side of the high-voltage line to the protection device on the other side of the high-voltage line by using the longitudinal optical fiber channel, and then make a difference between the first relative angle difference and the second relative angle difference;

Alternatively, the second relative angle difference on the other side of the high-voltage line is transmitted to the protection device on one side of the high-voltage line through a longitudinal optical fiber channel, and the difference between the first relative angle difference and the second relative angle difference is made.

During concrete implementation, the basis of proposing the method of the present invention is:

When a single-phase high-resistance grounding fault occurs on a high-voltage line, the zero-sequence current flows from the fault point to both sides of the high-voltage line. Considering that the zero-sequence impedance angle of the system on both sides of the high-voltage line is basically the same, the direction of the zero-sequence current on both sides of the high-voltage line is Basically in the same direction, as shown in Figure 2.

When an out-of-zone fault occurs on the high-voltage line, the zero-sequence current flows from the fault point to the far side of the high-voltage line through the near side of the high-voltage line. The zero-sequence current on the high-voltage line is through, so the direction of the zero-sequence current on both sides of the high-voltage line is reversed. As shown in Figures 3 and 4.

In the area where the high-voltage line occurs and the internal and external high-resistance grounding faults, the voltage directions of the phases on both sides of the high-voltage line are still close to the same direction, such as the A-phase voltage on one side of the high-voltage line (M side) and the opposite side of the high-voltage line (N side) The phase A voltage direction is close to the same direction, and the phase difference is less than 30°.

Because the protection devices on both sides of the high-voltage line cannot sample synchronously, the zero-sequence current phasors calculated after being collected by the protection devices on both sides of the high-voltage line cannot be directly compared in phase. However, the phase voltages on each side of the high-voltage line are synchronized with the zero-sequence current sampling, and the calculated phasors can be compared in phase.

The present invention is carried out by utilizing the above features.

Among them, the meanings of all the letters in Figure 2, Figure 3 and Figure 4 are:

I _OM is the zero-sequence current on the M side of the high-voltage line, and I _ON is the zero-sequence current on the N side of the high-voltage line;

U _AM is the A-phase voltage on the M side of the high-voltage line, and U _AN is the A-phase voltage on the N-side of the high-voltage line;

U _BM is the B-phase voltage on the M side of the high-voltage line, and U _BN is the B-phase voltage on the N-side of the high-voltage line;

U _CM is the C-phase voltage on the M side of the high-voltage line, and U _CN is the C-phase voltage on the N-side of the high-voltage line.

During specific implementation, one phase voltage of the three-phase voltage on one side (M side) of the high-voltage line and one phase voltage of the three-phase voltage on the other side (N side) of the high-voltage line are the same phase voltage, including:

If the A-phase voltage is greater than 30V, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the A-phase voltage;

If the voltage of phase A is less than 30V and the voltage of phase B is greater than 30V, the voltage of one phase of the three-phase voltage on one side of the high-voltage line and the voltage of one phase of the three-phase voltage on the other side of the high-voltage line is the voltage of phase B;

If the B-phase voltage is less than 30V and the C-phase voltage is greater than 30V, then one of the three-phase voltages on one side of the high-voltage line and one of the three-phase voltages on the other side of the high-voltage line is the C-phase voltage.

In addition, if the C-phase voltage is less than 30V, it can be directly determined that the longitudinal zero-sequence direction is the opposite direction, and there is no need to calculate the phase angle difference.

During specific implementation, the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages is determined according to the following formula:

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

The second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one of the three-phase voltages is determined according to the following formula:

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

Among them, X is the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages; Y is the first relative angle difference between the zero-sequence current on the other side of the high-voltage line and one of the three-phase voltages Two relative angle differences; I _o is the zero-sequence current, is any phase voltage in the three-phase voltage; when , X=Y=-1.

Specifically, the voltage phasor calculation adopts the power frequency full-cycle Fourier filter algorithm, and starts 20ms after the longitudinal zero-sequence protection starts.

When the phase A voltage is taken on both sides, the relative angle difference is: The phase difference calculation result adopts a range of 0° to 360°.

only if , X _A ＝-1, I _o is the zero-sequence current, is the phase A voltage.

When the B-phase voltage is taken on both sides, the relative angle difference is: The phase difference calculation result adopts a range of 0° to 360°.

only if , X _B ＝-1, I _o is the zero-sequence current, is the B-phase voltage.

When the phase C voltage is taken on both sides, the relative angle difference is: The phase difference calculation result adopts a range of 0° to 360°.

only if , X _C ＝-1, I _o is the zero-sequence current, is the phase C voltage.

Among them, X _A , X _B , and X _C are the relative angle differences between the zero-sequence current on one side of the high-voltage line and the voltages of phase A, phase B, and phase C;

Y _A , Y _B , and Y _C are the relative angle differences between the zero-sequence current on the other side of the high-voltage line and the voltages of phase A, phase B, and phase C, respectively.

During specific implementation, if the difference between the first relative angle difference and the second relative angle difference is within the preset angle difference range, the longitudinal zero-sequence direction is the positive direction; otherwise, the longitudinal zero-sequence direction is the reverse direction, including :

When X _A >-1 and Y _A >-1, if -60°<X _A -Y _A <60°, the longitudinal zero sequence direction is the positive direction, and the longitudinal zero sequence protection can operate; otherwise, the longitudinal zero sequence The sequence direction is the opposite direction, and the longitudinal zero-sequence protection does not operate;

When X _A ＝-1 or Y _A ＝-1, X _B >-1 and Y _B >-1, if -60°<X _B -Y _B <60°, the longitudinal zero-sequence direction is the positive direction, The longitudinal zero-sequence protection can operate; otherwise, the direction of the longitudinal zero-sequence protection is reversed, and the longitudinal zero-sequence protection does not operate;

When X _B ＝-1 or Y _B ＝-1, X _C >-1 and Y _C >-1, if -60°<X _C -Y _C <60°, the longitudinal zero sequence direction is the positive direction, The longitudinal zero-sequence protection can operate; otherwise, the direction of the longitudinal zero-sequence protection is reversed, and the longitudinal zero-sequence protection does not operate.

Based on the same inventive concept, an embodiment of the present invention also provides a high-voltage line longitudinal zero-sequence direction discrimination device, as described in the following embodiments. Since the problem-solving principle of the high-voltage line longitudinal zero-sequence direction discrimination device is similar to the high-voltage line longitudinal zero-sequence direction discrimination method, the implementation of the high-voltage line longitudinal zero-sequence direction discrimination device can refer to the high-voltage line longitudinal zero-sequence direction discrimination method implementation, the repetition will not be repeated. As used below, the term "unit" or "module" may be a combination of software and/or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementations in hardware, or a combination of software and hardware are also possible and contemplated.

Fig. 5 is a structural block diagram of a high-voltage line longitudinal zero-sequence direction discrimination device according to an embodiment of the present invention, as shown in Fig. 5 , including:

The first relative angle difference determination module 501 is used to determine the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one phase voltage of the three-phase voltage;

The second relative angle difference determination module 502 is used to determine the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one phase voltage of the three-phase voltage;

The longitudinal zero-sequence direction determination module 503 is used to determine the longitudinal zero-sequence direction as the positive direction if the difference between the first relative angle difference and the second relative angle difference is within the preset angle difference range; otherwise, the longitudinal zero-sequence direction for the opposite direction;

Wherein, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage.

This structure will be described below.

During specific implementation, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the same phase voltage, including:

If the A-phase voltage is greater than 30V, one phase voltage of the three-phase voltage on one side of the high-voltage line and one phase voltage of the three-phase voltage on the other side of the high-voltage line are the A-phase voltage;

If the voltage of phase A is less than 30V and the voltage of phase B is greater than 30V, the voltage of one phase of the three-phase voltage on one side of the high-voltage line and the voltage of one phase of the three-phase voltage on the other side of the high-voltage line is the voltage of phase B;

If the B-phase voltage is less than 30V and the C-phase voltage is greater than 30V, then one of the three-phase voltages on one side of the high-voltage line and one of the three-phase voltages on the other side of the high-voltage line is the C-phase voltage.

During specific implementation, it also includes:

If the C-phase voltage is less than 30V, then determine the longitudinal zero-sequence direction is the opposite direction.

During specific implementation, the first relative angle difference determining module 501 is specifically used for:

Determine the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one phase voltage of the three-phase voltage according to the following formula:

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

The second relative angle difference determining module 502 is specifically used for:

Determine the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and one phase voltage of the three-phase voltage according to the following formula:

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\frac{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; ;</span>$

Among them, X is the first relative angle difference between the zero-sequence current on one side of the high-voltage line and one of the three-phase voltages; Y is the first relative angle difference between the zero-sequence current on the other side of the high-voltage line and one of the three-phase voltages Two relative angle differences; I _o is the zero-sequence current, is any phase voltage in the three-phase voltage; when , X=Y=-1.

During specific implementation, the preset angle difference range is (-60°, 60°).

During specific implementation, the longitudinal zero-sequence direction determination module 503 is specifically used for:

When X _A >-1 and Y _A >-1, if -60°<X _A -Y _A <60°, the longitudinal zero-sequence direction is the positive direction; otherwise, the longitudinal zero-sequence direction is the reverse direction;

When X _A ＝-1 or Y _A ＝-1, X _B >-1 and Y _B >-1, if -60°<X _B -Y _B <60°, the longitudinal zero-sequence direction is the positive direction; Otherwise, the longitudinal zero-sequence direction is the opposite direction;

When X _B ＝-1 or Y _B ＝-1, X _C >-1 and Y _C >-1, if -60°<X _C -Y _C <60°, the longitudinal zero-sequence direction is the positive direction; Otherwise, the longitudinal zero-sequence direction is the opposite direction;

Among them, X _A , X _B , and X _C are the relative angle differences between the zero-sequence current on one side of the high-voltage line and the voltages of phase A, phase B, and phase C;

Y _A , Y _B , and Y _C are the relative angle differences between the zero-sequence current on the other side of the high-voltage line and the voltages of phase A, phase B, and phase C, respectively.

In summary, the present invention uses the first relative angle difference between the zero-sequence current on one side of the high-voltage line and a certain phase voltage, and compares it with the second relative angle difference between the zero-sequence current on the other side of the high-voltage line and the same phase voltage , to judge whether the longitudinal zero-sequence direction is forward or reverse. When one of the phase voltages occurs PT disconnection, other phase voltages can also be used to continue to judge, so it can avoid blocking the zero-sequence direction when non-three-phase PT disconnection occurs protection problem; in the event of a high-resistance fault, the use of phase voltage discrimination can also avoid the problem of incorrect action of zero-sequence directional elements caused by the small zero-sequence voltage and insufficient sensitivity; the key to this invention is the corresponding phase voltage and zero-sequence The phase difference of the current is compared to determine the zero-sequence direction, which fundamentally solves the problem of zero-sequence direction protection misoperation caused by the influence of the zero-sequence mutual inductance of the faulty line on the non-faulty line connected with the weak current and strong magnetic field of the same pole.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, various modifications and changes may be made to the embodiments of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (12)

1. a high-tension line vertical connection zero sequence direction method of discrimination, is characterized in that, comprising:

Determine that the first relative angle of the phase voltage in the zero-sequence current of high-tension line side and three-phase voltage is poor;

Determine that the second relative angle of the phase voltage in the zero-sequence current of high-tension line opposite side and three-phase voltage is poor;

If the difference of the first relative angle difference and the second relative angle difference is in predetermined angle difference scope, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Wherein, the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is in-phase voltage.

2. high-tension line as claimed in claim 1 vertical connection zero sequence direction method of discrimination, is characterized in that, the phase voltage in the phase voltage in the three-phase voltage of described high-tension line side and the three-phase voltage of high-tension line opposite side is in-phase voltage, comprising:

If A phase voltage is greater than 30V, then the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is A phase voltage;

If A phase voltage is less than 30V, and B phase voltage is greater than 30V, then the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is B phase voltage;

If B phase voltage is less than 30V, and C phase voltage is greater than 30V, then the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is C phase voltage.

3. high-tension line as claimed in claim 2 vertical connection zero sequence direction method of discrimination, is characterized in that, also comprise:

If C phase voltage is less than 30V, then determine that vertical connection zero sequence direction is in the other direction.

4. high-tension line as claimed in claim 2 vertical connection zero sequence direction method of discrimination, is characterized in that, the first relative angle difference of the phase voltage in the zero-sequence current of described high-tension line side and three-phase voltage is determined by following formula:

$X=\arg \frac{\stackrel{\&CenterDot;}{U}}{I_o};$

Second relative angle difference of the phase voltage in the zero-sequence current of described high-tension line opposite side and three-phase voltage is determined by following formula:

$Y=\arg \frac{\stackrel{\&CenterDot;}{U}}{I_o};$

Wherein, X is that the first relative angle of a phase voltage in the zero-sequence current of high-tension line side and three-phase voltage is poor; Y is that the second relative angle of a phase voltage in the zero-sequence current of high-tension line opposite side and three-phase voltage is poor; I _ofor zero-sequence current, for the arbitrary phase voltage in three-phase voltage; When time, X=Y=-1.

5. high-tension line as claimed in claim 4 vertical connection zero sequence direction method of discrimination, is characterized in that, described predetermined angle difference scope is (-60 °, 60 °).

6. high-tension line as claimed in claim 5 vertical connection zero sequence direction method of discrimination, is characterized in that, if the difference of described first relative angle difference and the second relative angle difference is in predetermined angle difference scope, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction, comprising:

Work as X _a>-1 and Y _aduring >-1, if-60 ° of < X _a-Y _a< 60 °, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Work as X _a=-1 or Y _a=-1, X _b>-1 and Y _bduring >-1, if-60 ° of < X _b-Y _b< 60 °, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Work as X _b=-1 or Y _b=-1, X _c>-1 and Y _cduring >-1, if-60 ° of < X _c-Y _c< 60 °, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Wherein, X _a, X _b, X _cthe zero-sequence current being respectively high-tension line side is poor with the relative angle of A phase, B phase, C phase voltage;

Y _a, Y _b, Y _cthe zero-sequence current being respectively high-tension line opposite side is poor with the relative angle of A phase, B phase, C phase voltage.

7. a high-tension line vertical connection zero sequence direction discriminating gear, is characterized in that, comprising:

First relative angle difference determination module, poor for determining the first relative angle of the phase voltage in the zero-sequence current of high-tension line side and three-phase voltage;

Second relative angle difference determination module, poor for determining the second relative angle of the phase voltage in the zero-sequence current of high-tension line opposite side and three-phase voltage;

Vertical connection zero sequence direction determination module, if for the difference of the first relative angle difference and the second relative angle difference in predetermined angle difference scope, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Wherein, the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is in-phase voltage.

8. high-tension line as claimed in claim 7 vertical connection zero sequence direction discriminating gear, is characterized in that, the phase voltage in the phase voltage in the three-phase voltage of described high-tension line side and the three-phase voltage of high-tension line opposite side is in-phase voltage, comprising:

If A phase voltage is greater than 30V, then the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is A phase voltage;

If A phase voltage is less than 30V, and B phase voltage is greater than 30V, then the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is B phase voltage;

If B phase voltage is less than 30V, and C phase voltage is greater than 30V, then the phase voltage in the phase voltage in the three-phase voltage of high-tension line side and the three-phase voltage of high-tension line opposite side is C phase voltage.

9. high-tension line as claimed in claim 8 vertical connection zero sequence direction discriminating gear, is characterized in that, also comprise:

If C phase voltage is less than 30V, then determine that vertical connection zero sequence direction is in the other direction.

10. high-tension line as claimed in claim 8 vertical connection zero sequence direction discriminating gear, is characterized in that, described first relative angle difference determination module specifically for:

Poor by the first relative angle of the phase voltage in the zero-sequence current of following formula determination high-tension line side and three-phase voltage:

$X=\arg \frac{\stackrel{\&CenterDot;}{U}}{I_o};$

Described second relative angle difference determination module specifically for:

Poor by the second relative angle of the phase voltage in the zero-sequence current of following formula determination high-tension line opposite side and three-phase voltage:

$Y=\arg \frac{\stackrel{\&CenterDot;}{U}}{I_o};$

Wherein, X is that the first relative angle of a phase voltage in the zero-sequence current of high-tension line side and three-phase voltage is poor; Y is that the second relative angle of a phase voltage in the zero-sequence current of high-tension line opposite side and three-phase voltage is poor; I _ofor zero-sequence current, for the arbitrary phase voltage in three-phase voltage; When time, X=Y=-1.

11. high-tension lines as claimed in claim 10 vertical connection zero sequence direction discriminating gear, is characterized in that, described predetermined angle difference scope is (-60 °, 60 °).

12. high-tension lines as claimed in claim 11 vertical connection zero sequence direction discriminating gear, is characterized in that, described vertical zero sequence direction determination module specifically for:

Work as X _a>-1 and Y _aduring >-1, if-60 ° of < X _a-Y _a< 60 °, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Work as X _a=-1 or Y _a=-1, X _b>-1 and Y _bduring >-1, if-60 ° of < X _b-Y _b< 60 °, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Work as X _b=-1 or Y _b=-1, X _c>-1 and Y _cduring >-1, if-60 ° of < X _c-Y _c< 60 °, then vertical connection zero sequence direction is positive dirction; Otherwise vertical connection zero sequence direction is in the other direction;

Wherein, X _a, X _b, X _cthe zero-sequence current being respectively high-tension line side is poor with the relative angle of A phase, B phase, C phase voltage;

Y _a, Y _b, Y _cthe zero-sequence current being respectively high-tension line opposite side is poor with the relative angle of A phase, B phase, C phase voltage.