CN101038316A - Circuit protection order component phase selectiing method using both end information - Google Patents

Abstract

The present invention relates to a circuit protecting order component phase selecting method adopting two-end information. First, synchronous samplings of the phase current of the own side and the opposite side of the circuit are performed in a preset sampling speed, and the sampling value of the phase current of the opposite side is transmitted to the own side; then, the differential current vectors of each phase of said sampling result is calculated and the positive-sequence vector, the negative-sequence vector and the zero- sequence vector I1d, I2d, I3d are extracted using the A phase as the standard phase; the negative-sequence vector and the zero- sequence vector of the differential current are compared: -90 DEG<ARG(*[2d]/*[0d])<30 DEG is the ground fault of phase A or BC; 150 DEG <ARG(*[2d]/*[0d]) <270 DEG is the ground fault of phase B or CA; 30 DEG<ARG(*[2d]/*[0d])< 150 DEG is the ground fault of phase C or AB. The characteristics are: the method also includes the steps of determining of the ground fault of a single-phase or two-phase in each subarea according to the value of the positive-sequence vector, the negative-sequence vector and the zero- sequence vector of the differential current. If *[2d] + *[0d] > 1.5*[1d] , it is the single-phase groud fault; or, it is the two-phase ground fualt. The method adopts a differential current to performe judging, and the principle is simple and reliable and is not influenced by the running mode of the system. The device has a high sensitivity and can select phase correctly when a conversion fault occurs.

Description

Adopt the circuit protection order component phase selectiing method of both end information

Technical field

The invention belongs to the power system automation technology field, relate to a kind of circuit protection order component phase selectiing method that adopts both end information.

Background technology

When breaking down on electric system high pressure, the extra high voltage network, extensively adopt the method for single-pole reclosing in China's high-pressure system, because the needs that choosing is tripped mutually, phase selection element becomes the critical elements in the high pressure protector.

Traditional phase selection element can only adopt single-ended voltage and current amount to differentiate, sudden change amount phase selection element, the impedance phase selection element of phase current difference, the preface component phase selection element of single-ended amount are generally arranged, these phase selection elements are owing to only use single-ended amount, often be subjected to the influence of the method for operation bigger, when some complicacy faults, phase selection element often moves incorrect in addition.

In addition along with the fast-developing of the optical fiber and digital communication technology and the progressively application in electric system thereof, this side can receive the analog quantity information of circuit offside reliably, the phase-selecting method that utilizes above-mentioned single-ended amount phase selection element can not satisfy the needs of development owing to its deficiency.

The division of phase region such as following table are confirmed in existing preface component choosing mutually according to negative phase-sequence under the different faults situation and zero-sequence current relative phase:

In proper order	I2d hysteresis I0d phase angle (degree)	Possible fault type
			(1)	-30～+30	A, BC ground connection
(2)	+30～+90	AB ground connection
			(3)	+90～+150	C, AB ground connection
(4)	-150～+150	CA ground connection
			(5)	-150～-90	B, CA ground connection
(6)	-90～-30	BC ground connection

(2), (4), (6) are the separate phase region of single failure in the table; directly confirm as corresponding phase-to phase fault; in (1), (3), (5) phase region comprises single-phase and alternate two kinds of fault types; because two kinds of fault types is separate always incoherent; adopt alternate impedance exclusive method, if promptly protector measuring to alternate resistance value in the alternate impedance ranges of adjusting, then confirming as is phase-to phase fault; otherwise, confirm as corresponding singlephase earth fault.The reason that adopts alternate impedance exclusive method is to think that alternate impedor is for phase to phase fault total energy precision maneuver.At present; utilize the subregion of preface electric current and measure impedance ratio method; as the phase selection element during the out-of-step blocking during out-of-step blocking; measuring impedance (being non-fault phase especially) is subjected to the influence of system oscillation very big; the measurement impedance ratio can be falsely dropped single-phase earthing than this auxiliary element and be line to line fault earth fault; also the erroneous judgement of line to line fault ground connection can be single-phase earthing, the ability of its anti-transition resistance is also very poor, and this is the big hidden danger in the current ultra-high-tension power transmission line protection.

Summary of the invention

For addressing the above problem, the present invention aims to provide a kind of circuit protection order component phase selectiing method that adopts both end information, correctly judges single-phase and phase to phase fault, to improve the correct operation of phase selection element, satisfies the circuit choosing needs of tripping operation mutually.

For addressing the above problem, the present invention is achieved by the following technical solutions:

A kind of circuit protection order component phase selectiing method that adopts both end information may further comprise the steps:

(1), sampling step: the phase current to this side of transmission line of electricity and offside carries out synchronized sampling with predetermined sampling rate, and the phase current sampling value of offside is transferred to this side;

(2), computing step: above-mentioned sampled result is handled, utilized the full-wave fourier algorithm amplitude to calculate the difference current vector of each phase, and be the positive-sequence component of benchmark extraction difference current mutually with A

Negative sequence component

Zero-sequence component

(3), comparison step: the negative sequence component and the zero-sequence component of difference current are carried out relative phase relatively, and comparative result is divided into three zones:

The A district:

The A district is A phase earth fault or BC double earthfault;

The B district:

The B district is B phase earth fault or CA double earthfault;

The C district:

The C district is C phase earth fault or AB double earthfault;

It is characterized in that: it also comprises: four, determining step: in each subregion, carry out determining of single-phase fault and double earthfault according to the size of the positive-sequence component of difference current, negative sequence component, zero-sequence component, if Be defined as singlephase earth fault; Otherwise, be defined as double earthfault.

The invention has the beneficial effects as follows: this method adopts difference current (when the circuit troubles inside the sample space, be exactly the fault current of fault branch in fact) judge that principle is simple and reliable, be not subjected to the influence of system operation mode, it is highly sensitive, also can accurately select phase during evolved fault.

Embodiment

In service at electric system high pressure, extra high voltage network, this side of transmission line of electricity and the phase current of offside are carried out synchronized sampling with predetermined sampling rate, and the phase current sampling value of offside is transferred to this side; Above-mentioned sampled result is handled, utilized the full-wave fourier algorithm amplitude to calculate the difference current vector of each phase, and be the positive-sequence component of benchmark extraction difference current mutually with A

Negative sequence component

Zero-sequence component

The negative sequence component and the zero-sequence component of difference current are carried out relative phase relatively, and comparative result is divided into three zones:

The A district: The A district is A phase earth fault or BC double earthfault;

The B district:

The B district is B phase earth fault or CA double earthfault;

The C district:

The C district is C phase earth fault or AB double earthfault;

In each subregion, carry out determining of single-phase fault and double earthfault according to the size of the positive-sequence component of difference current, negative sequence component, zero-sequence component, if

Be defined as singlephase earth fault; Otherwise, be defined as double earthfault.This preface component phase-selecting method adopts difference current to judge that be not subjected to the influence of system operation mode, it is highly sensitive, fully satisfies the circuit choosing needs of tripping operation mutually.

Below announced the present invention with preferred embodiment, so it is not in order to restriction the present invention, and all technical schemes that scheme obtained of taking to be equal to replacement or equivalent transformation all drop in protection scope of the present invention.

Claims (1)

1, adopt the circuit protection order component phase selectiing method of both end information, may further comprise the steps:

(1), sampling step: the phase current to this side of transmission line of electricity and offside carries out synchronized sampling with predetermined sampling rate, and the phase current sampling value of offside is transferred to this side;

(2), computing step: above-mentioned sampled result is handled, utilized the full-wave fourier algorithm amplitude to calculate the difference current vector of each phase, and be the positive-sequence component of benchmark extraction difference current mutually with A

Negative sequence component

Zero-sequence component

(3), comparison step: the negative sequence component and the zero-sequence component of difference current are carried out relative phase relatively, and comparative result is divided into three zones:

The A district:

The A district is A phase earth fault or BC double earthfault;

The B district:

The B district is B phase earth fault or CA double earthfault;

The C district:

The C district is C phase earth fault or AB double earthfault;

It is characterized in that: it also comprises: four, determining step: in each subregion, carry out determining of single-phase fault and double earthfault according to the size of the positive-sequence component of difference current, negative sequence component, zero-sequence component, if ${\stackrel{\&CenterDot;}{I}}_{2d}+{\stackrel{\&CenterDot;}{I}}_{0d}>1.5\&CenterDot;{\stackrel{\&CenterDot;}{I}}_{1d},$ Be defined as singlephase earth fault; Otherwise, be defined as double earthfault.