CN104330705B - Circuit inter-phase fault single-end ranging based on phase-to phase fault location factor - Google Patents

Abstract

The invention discloses a kind of circuit inter-phase fault single-end ranging based on phase-to phase fault location factor.The inventive method computing electric power line first protects installation place to the fault impedance and the ratio of the line impedance at line protection installation place to line protection setting range of phase fault point, obtains electric transmission line phase fault location factor b；Then it is l to choose fault distance initial value_fault, with the incremental every bits on computing electric power line successively of fixed step size Δ lValue, until transmission line of electricity total length；Choose and met on transmission line of electricityMinimum distance of the point away from line protection installation place is fault distance.The influence of voltage at interphase short circuit fault point of power transmission line, transition resistance and load current to electric transmission line phase fault single end distance measurement precision is eliminated in the inventive method principle, with very high range accuracy, ultrahigh voltage alternating current transmission lines phase fault single end distance measurement is particularly suitable for use in.

Description

Circuit inter-phase fault single-end ranging based on phase-to phase fault location factor

Technical field

The present invention relates to Relay Protection Technology in Power System field, concretely relate to a kind of based on phase-to phase fault position The circuit inter-phase fault single-end ranging of the factor.

Background technology

Originated and divided according to electrical quantity, fault distance-finding method is broadly divided into both-end distance measuring method and method of single end distance measurement.It is double Distance-finding method is held to carry out fault location using transmission line of electricity two ends electrical quantity, it is necessary to electric by data transmission channel acquisition opposite end Amount, it is strong to data transmission channel dependence, also easily influenceed in actual use by both-end sampling value synchronization.Extra-high-voltage alternating current is defeated Electric line is often long-distance transmission line, and the data transmission channel needed for laying ranging needs additional investment substantial contribution, because This, method of single end distance measurement has more practicality than both-end distance measuring method.Method of single end distance measurement is merely with transmission line of electricity one end electrical quantity Fault location is carried out, without communication and data synchronizer, operating cost is low and algorithmic stability, in senior middle school's low-voltage electricity transmission line Obtain extensive use.

At present, method of single end distance measurement is broadly divided into traveling wave method and impedance method.Traveling wave method utilizes the transmission of fault transient travelling wave Property carries out one-end fault ranging, and precision is high, is not influenceed by the method for operation, excessive resistance etc., but requires very high to sample rate, needs Special wave recording device is wanted, application cost is high.Impedance method utilizes the voltage after failure, the magnitude of current to calculate Fault loop impedance, root The characteristic being directly proportional according to line length to impedance carries out one-end fault ranging, simple and reliable, but range accuracy is by transition resistance Serious with the influence of the factor such as load current, when especially transition resistance is larger, impedance method distance measurement result can substantial deviation true fault Distance, or even there is ranging failure.Due to there is larger capacitance current along UHV transmission line, when extra-high voltage is defeated During electric line occurs during high resistant short trouble, single-ended impedance method distance measurement result meeting substantial deviation true fault distance, it is impossible to meet The application requirement at scene.Therefore, the single-ended impedance method modeled using lumped parameter is not directly applicable UHV transmission line One-end fault ranging.

The content of the invention

It is an object of the present invention to overcome the deficiencies of the prior art, and to provide a kind of based on phase-to phase fault location factor Circuit inter-phase fault single-end ranging.The inventive method computing electric power line first protects installation place to phase fault point Fault impedance and line protection installation place to line protection setting range at line impedance ratio, obtain defeated Electric line phase-to phase fault location factor b；Then it is l to choose fault distance initial value_fault, by fixed step size Δ l incrementally successively in terms of Calculate every bit on transmission line of electricityValue, until transmission line of electricity total length；Choose and met on transmission line of electricityMinimum distance of the point away from line protection installation place is fault distance.The inventive method uses long line Equation accurately describes the physical characteristic of transmission line of electricity, the ability influenceed with natural anti-distribution capacity.The inventive method principle On eliminate voltage at interphase short circuit fault point of power transmission line, transition resistance and load current to electric transmission line phase fault list The influence of range accuracy is held, with very high range accuracy, ultrahigh voltage alternating current transmission lines phase fault is particularly suitable for use in Single end distance measurement.

To complete above-mentioned purpose, the present invention is adopted the following technical scheme that：

Circuit inter-phase fault single-end ranging based on phase-to phase fault location factor, it is characterised in that including as follows according to Sequence step：

(1) the failure voltage between phases of protector measuring line protection installation placeFailure three-phase currentWith The alternate negative-sequence current of failureWherein, φ φ=AB, BC, CA phase；

(2) protection device calculates γ₁l_setHyperbolic cosine function value ch (γ₁l_set), calculate γ₁l_setTanh letter Numerical value th (γ₁l_set)；Wherein, l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁For power transmission line Road positive sequence propagation coefficient；

(3) computing electric power line phase-to phase fault location factor b：

Wherein, φ φ=AB, BC, CA phase；l_setFor line protection setting range, 0.85 times of transmission line length is taken； γ₁For electric transmission line positive sequence propagation coefficient；Z_c1For electric transmission line positive sequence wave impedance；ForReal part；ForImaginary part；ForReal part； ForImaginary part；ForReal part；ForImaginary part；

(4) it is l that protection device, which chooses fault distance initial value,_fault, it is incremented by with fixed step size Δ l, power transmission line is calculated successively On road at every bitValue, until transmission line of electricity total length；Wherein, fixed step size Δ l takes 0.001l；L is defeated Electric line length；l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁Passed for electric transmission line positive sequence Broadcast coefficient；Z_c1For electric transmission line positive sequence wave impedance；Fault distance initial value l_fault0 beginning is taken, it is incrementally straight with fixed step size Δ l Terminate to transmission line of electricity total length l；

(5) protection device is chosen and met on transmission line of electricityMinimum point is installed away from line protection The distance at place is fault distance；Wherein, th (γ₁l_fault) it is γ₁l_faultHyperbolic tangent function value.

The present invention compared with prior art, with following positive achievement：

The inventive method fault impedance and transmission of electricity of the computing electric power line protection installation place to phase fault point first The ratio of line impedance at route protection installation place to line protection setting range, obtains electric transmission line phase fault position Put factor b；Then it is l to choose fault distance initial value_fault, with fixed step size Δ l incrementally successively on computing electric power line it is each PointValue, until transmission line of electricity total length；Choose and met on transmission line of electricityMinimum point Distance away from line protection installation place is fault distance.The inventive method accurately describes transmission line of electricity using long-line equation Physical characteristic, the ability influenceed with natural anti-distribution capacity.Transmission line of electricity is eliminated in the inventive method principle alternate short The influence of road fault point voltage, transition resistance and load current to electric transmission line phase fault single end distance measurement precision, has Very high range accuracy, is particularly suitable for use in ultrahigh voltage alternating current transmission lines phase fault single end distance measurement.

Brief description of the drawings

Fig. 1 is the multi-line power transmission system schematic of the application present invention.

Embodiment

Technical scheme is expressed in further detail below according to Figure of description.

Fig. 1 is the multi-line power transmission system schematic of the application present invention.CVT is that voltage transformer, CT are Current Mutual Inductance in Fig. 1 Device.Current waveform of the protection device to the voltage transformer CVT of line protection installation place potential and current transformers CT Progress, which is sampled, obtains voltage, current instantaneous value.

Protection device is protected using Fourier algorithm computing electric power line to sample obtained voltage, current instantaneous value and installed The failure voltage between phases at placeFailure three-phase currentNegative-sequence current alternate with failureWherein, φ φ=AB, BC, CA Phase.

Protection device calculates γ₁l_setHyperbolic cosine function value ch (γ₁l_set)。

Protection device calculates γ₁l_setHyperbolic tangent function value th (γ₁l_set)。

Wherein, l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁For electric transmission line positive sequence Propagation coefficient.

Protection device computing electric power line phase-to phase fault location factor b：

Wherein, φ φ=AB, BC, CA phase；l_setFor line protection setting range, 0.85 times of transmission line length is taken； γ₁For electric transmission line positive sequence propagation coefficient；Z_c1For electric transmission line positive sequence wave impedance；ForReal part；ForImaginary part；ForReal part； ForImaginary part；ForReal part；ForImaginary part.

It is l that protection device, which chooses fault distance initial value,_fault, it is incremented by with fixed step size Δ l, successively on computing electric power line At every bitValue, until transmission line of electricity total length；Wherein, fixed step size Δ l takes 0.001l；L is transmission of electricity Line length；l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁Propagated for electric transmission line positive sequence Coefficient；Z_c1For electric transmission line positive sequence wave impedance；Fault distance initial value l_faultTake 0 beginning, with fixed step size Δ l be incremented by until Transmission line of electricity total length l terminates；th(γ₁l_fault) it is γ₁l_faultHyperbolic tangent function value.

Protection device is chosen and met on transmission line of electricityMinimum point is away from line protection installation place Distance is fault distance.

The inventive method fault impedance and transmission of electricity of the computing electric power line protection installation place to phase fault point first The ratio of line impedance at route protection installation place to line protection setting range, obtains electric transmission line phase fault position Put factor b；Then it is l to choose fault distance initial value_fault, with fixed step size Δ l incrementally successively on computing electric power line it is each PointValue, until transmission line of electricity total length；Choose and met on transmission line of electricityMinimum point Distance away from line protection installation place is fault distance.The inventive method accurately describes transmission line of electricity using long-line equation Physical characteristic, the ability influenceed with natural anti-distribution capacity.Transmission line of electricity is eliminated in the inventive method principle alternate short The influence of road fault point voltage, transition resistance and load current to electric transmission line phase fault single end distance measurement precision, has Very high range accuracy, is particularly suitable for use in ultrahigh voltage alternating current transmission lines phase fault single end distance measurement.

The preferred embodiment of the present invention is the foregoing is only, but protection scope of the present invention is not limited thereto, and is appointed What those familiar with the art the invention discloses technical scope in, the change or replacement that can be readily occurred in, all It should be included within the scope of the present invention.

Claims (1)

1. the circuit inter-phase fault single-end ranging based on phase-to phase fault location factor, it is characterised in that including as follows sequentially Step：

(1) on protector measuring transmission line of electricity protection device installation place failure voltage between phasesFailure three-phase currentWith The alternate negative-sequence current of failureWherein, φ φ=AB, BC, CA phase；

(2) protection device calculates γ₁l_setHyperbolic cosine function value ch (γ₁l_set), calculate γ₁l_setHyperbolic tangent function value th(γ₁l_set)；Wherein, l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁For transmission line of electricity just Sequence propagation coefficient；

(3) protection device computing electric power line phase-to phase fault location factor b：

$b=\frac{\mathrm{Re}\left({\stackrel{\·}{U}}_{\mathrm{\φ}\mathrm{\φ}}\right)In\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ}\mathrm{\φ}2}}{ch\left({\mathrm{\γ}}_1{l}_{set}\right)}\right)-\mathrm{Im}\left({\stackrel{\·}{U}}_{\mathrm{\φ}\mathrm{\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ}\mathrm{\φ}2}}{ch\left({\mathrm{\γ}}_1{l}_{set}\right)}\right)}{\mathrm{Re}\left(Z_{c1}th\right({\mathrm{\γ}}_1{l}_{set}\left){\stackrel{\·}{I}}_{\mathrm{\φ}\mathrm{\φ}}\right)In\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ}\mathrm{\φ}2}}{ch\left({\mathrm{\γ}}_1{l}_{set}\right)}\right)-Im\left(Z_{c1}th\right({\mathrm{\γ}}_1{l}_{set}\left){\stackrel{\·}{I}}_{\mathrm{\φ}\mathrm{\φ}}\right)\mathrm{Re}\left(\frac{{\stackrel{\·}{I}}_{\mathrm{\φ}\mathrm{\φ}2}}{ch\left({\mathrm{\γ}}_1{l}_{set}\right)}\right)}$

Wherein, φ φ=AB, BC, CA phase；l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁For Electric transmission line positive sequence propagation coefficient；Z_c1For electric transmission line positive sequence wave impedance；ForReal part；ForImaginary part；ForReal part； ForImaginary part；ForReal part；ForImaginary part；

(4) it is l that protection device, which chooses fault distance initial value,_fault, it is incremented by with fixed step size Δ l, successively on computing electric power line At every bitValue, until transmission line of electricity total length；Wherein, fixed step size Δ l takes 0.001l；L is power transmission line Road length；l_setFor line protection setting range, 0.85 times of transmission line length is taken；γ₁Propagated for electric transmission line positive sequence and be Number；Z_c1For electric transmission line positive sequence wave impedance；Fault distance initial value l_fault0 beginning is taken, is incremented by with fixed step size Δ l until defeated Electric line total length l terminates；

(5) protection device is chosen and met on transmission line of electricityMinimum point is installed away from line protection The distance at place is fault distance；Wherein, th (γ₁l_fault) it is γ₁l_faultHyperbolic tangent function value.