CN106526410A - Small-current grounding system high-resistance grounding fault positioning method based on transient current projection component amplitude comparison - Google Patents

Abstract

A small-current grounding system high-resistance grounding fault positioning method based on transient current projection component amplitude comparison belongs to the field of power distribution network fault detection. The method settles a problem of small-current grounding system high-resistance grounding fault positioning and is a positioning method which utilizes projection component amplitude comparison of transient zero-sequence current of each monitoring point at upstream and downstream of each segment on bus transient zero-sequence voltage. According to a fault line selecting result, the projection components of the transient zero-sequence current at upstream and downstream of each segment in a faulted line on the bus transient zero-sequence voltage are calculated. A characteristic value which comprises projection component polarity and amplitude information of each monitoring point is compared. One second value of the characteristic value of a largest projection component is set as a threshold. The segment in which the difference between the characteristic values of the projection components of the transient zero-sequence current at upstream and downstream of the segment is larger than the threshold is selected as the faulted segment. If the difference between the characteristic values of the projection components of the transient zero-sequence current at upstream and downstream of each segment is lower than the threshold, a line end fault is determined. The small-current grounding system high-resistance grounding fault positioning method settles a problem of positioning the high-resistance grounding fault in the small-current grounding system and furthermore has high practical application value.

Description

A kind of small current neutral grounding system high resistant based on transient current projection components amplitude com parison Earth design method

Technical field

The present invention relates to a kind of small current neutral grounding system high resistive fault selection method, it is adaptable to which small current neutral grounding mode is matched somebody with somebody Electric system, belongs to distribution network failure detection field.

Background technology

Affected apart from low factor by natural environment, fixed track usage plan, the single-phase of Jing imperfectly conduting metals is often occurred in power distribution network High resistance earthing fault, such as wire fall in meadow, road, sand ground, pool etc..According to incompletely statistics, high resistance ground accounts for connecing The 5-10% of earth fault sum.It is high resistance earthing fault that French small current neutral grounding system has more than 12% earth fault.Due to The reason such as high resistance earthing fault electric current little (generally A levels), trouble point be unstable, when distribution line occurs permanent high resistance ground It is difficult to be detected after failure so that system long-time operates with failure, and this may cause phase-to phase fault or short trouble, expands Fault coverage.Therefore, after circuit occurs high resistive fault, need quickly to navigate to fault section and make corresponding quarantine measures. Especially for resonant earthed system, due to the compensating action of arc suppression coil, faulty line fault section power current and sound Section compares the reasons such as no obvious fault feature, the high resistance earthing fault positioning of resonant earthed system remain one it is very big Challenge.

In recent years, when there is single-phase (small current) earth fault in small current neutral grounding mode power distribution network, select in faulty line On the basis of selecting, the localization of faults distance or fault section, can further reduce trouble shoot and repair time, little electricity will be become Stream Earth Fault Detection technical research and focus, the emphasis of application.It is existing can for low-impedance earthed system fault section location method It is divided into two classes：One class is active localization method, produces larger current perturbation or using artificial using primary equipment action Directly the compensativity that specific currents adjust arc suppression coil is injected to system, fault section is determined according to zero-sequence current variable quantity；Separately One class is passive type localization method, using the transient signal amplitude com parison in earth fault transient process, Polarity comparision, power side To etc. principle carry out fault location.Existing low-resistance (metallicity) Earth design is not yet fully solved, and is not suitable for High resistance earthing fault, therefore even more have no time to attend to regard to the unconspicuous high resistance earthing fault location technology of the electric measure feature of failure Research, so fresh rare to related research report.

For small current neutral grounding system, power current itself cannot directly to fault detect (work without obvious fault feature The frequency active component of current is possible in theory, but content is less, easily affected by TV/TA Transfer characteristics, and practicality has larger difficulty). This patent is using the transient state electricity that parallel resonance is produced between arc suppression coil and system direct-to-ground capacitance in high resistance earthing fault transient process Tolerance realizes that fault location, by with unique advantage, is provided for small current neutral grounding system high resistance earthing fault Study of location One brand-new thinking, has extensive actual application value.

The content of the invention

It is an object of the invention to fault-location problem when there is high resistance ground in solving small current neutral grounding system, proposes One kind projects component waveform on bus transient voltage based on transient current and compares, it is adaptable to which the small current of terminal monitoring circuit connects The high resistance earthing fault localization method on ground mode distribution system (there is the section surrounded by three or more monitoring points), which is special Levy and be：Terminal online acquisition zero-sequence current and residual voltage, when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (one As U_th1=15V, U_th2=90V), then illustrate that system occurs high resistance earthing fault, carries out fault location according to the following steps：

A. when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then say There is high resistance earthing fault in bright system, electric substation's terminal starts, and selects faulty line, and route selection result and faulty line are exported Zero-sequence current gathered data reports main website；

B., when zero mode voltage or zero mould jump-value of current surmount preset threshold, each line feed terminals start, by failure zero sequence Voltage x current gathered data reports main website；

C. main website receives electric substation's terminal and each monitoring point residual voltage current acquisition data of feeder line, to residual voltage u_b、 The each monitoring point zero-sequence current i of faulty line_0jData are filtered, and extract its transient state component i respectively_{0j_T}、u_{b_T}, to perfecting circuit Terminal data is then disregarded；

D. faulty line each monitoring point transient zero-sequence current is projected to bus transient zero-sequence voltage, according to following formula Calculate projection components i of each monitoring point transient zero-sequence current_{0j_T_P}：

E. calculate characteristic value I comprising projection components polarity with amplitude information_{0j_T_P}：

F. 1/2nd of the characteristic value of calculating maximal projection component are threshold value I_th：

G. calculate difference γ of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream_km：

γ_km=I_{0m_T_P}-I_{0k_T_P}

If there is γ_km＞ i_th, then the section is fault section, if there is no γ_km＞ i_th, then the circuit most end section be Fault section.

Description of the drawings

The present invention is illustrated further with specific embodiment below in conjunction with the accompanying drawings：

Accompanying drawing 1 is a kind of typical distribution automation positioning system structure schematic diagram；

Accompanying drawing 2 is route selection FB(flow block)；

Accompanying drawing 3 is typical distribution circuit emulation model；

When in accompanying drawing 4 (a) (b) (c) respectively attached system shown in Figure 3, generation earth resistance is the high resistance earthing fault of 30 Ω The zero-sequence component of each candidate monitoring point current bus bar voltage, transient state component and projection components comparison of wave shape；

There is the high resistance earthing fault that earth resistance is 1500 Ω in being respectively attached system shown in Figure 3 in accompanying drawing 5 (a) (b) (c) When the zero-sequence component of each candidate monitoring point current bus bar voltage, transient state component and projection components comparison of wave shape；

Specific embodiment

For achieving the above object, plan of the present invention is realized with following technical proposals：

I, low current grounding alignment system as shown in figure 1 based on distribution automation system platform, by installing In the station inside transformer station terminal (low-current ground fault line selection device), be installed on the line terminal of each monitoring point of circuit (FTU) low current grounding positioning master station and the communication network composition of master control room, are installed on.The alignment system Concrete workflow Journey is as follows：

1) normal runtime system workflow

Line feed terminals in circuit are constantly in each monitoring point zero-sequence current of circuit and residual voltage (when having ready conditions) letter The state of number sampling, and zero-sequence voltage samples signal or zero-sequence current variable quantity and device are started into threshold value be compared and sentence Whether disconnected bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), judge whether symbol Attach together and put entry condition；Line selection apparatus are responsible for monitoring bus residual voltage and each bar feeder line outlet zero sequence current signal, normal work Monitoring signals are sampled when making, and the sampled value of residual voltage and device are started into threshold value and be compared, judge circuit In whether faulty generation；Positioning master station is responsible for receiving the fault data that line feed terminals and line selection apparatus are reported, and carries out failure Line feed terminals and line selection apparatus can be carried out status poll during normal work by positioning, it is to avoid device is deactivated state.

2) working-flow during failure

When there is low current grounding in circuit, circuit line feed terminals are according to zero-sequence current variable quantity or residual voltage (when having ready conditions) signal enabling, records the failure residual voltage current signal of three cycles in each monitoring point, and will mark with the time The fault data of label reports to positioning master station；Line selection apparatus start according to residual voltage at bus, when bus residual voltage amplitude In U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then illustrate that system occurs high resistance earthing fault, starts dress Put, and record residual voltage at bus, the zero sequence current signal in each bar feeder line bus exit, trouble duration, failure and send out Raw time, faulty line, the equal fault data of failure, and fault data work corresponding conversion is reported to into positioning master station；Positioning Main website is responsible for receiving the fault data that line selection apparatus and line feed terminals are reported, and carries out fault section location according to following steps.

A. when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then say There is high resistance earthing fault in bright system, electric substation's terminal starts, and selects faulty line, and route selection result and faulty line are exported Zero-sequence current gathered data reports main website；

B., when zero mode voltage or zero mould jump-value of current surmount preset threshold, each line feed terminals start, by failure zero sequence Voltage x current gathered data reports main website；

C. main website receives electric substation's terminal and each monitoring point residual voltage current acquisition data of feeder line, to residual voltage u_b、 The each monitoring point zero-sequence current i of faulty line_0jData are filtered, and extract its transient state component i respectively_{0j_T}、u_{b_T}, to perfecting circuit Terminal data is then disregarded；

D. faulty line each monitoring point transient zero-sequence current is projected to bus transient zero-sequence voltage, according to following formula Calculate projection components i of each monitoring point transient zero-sequence current_{0j_T_P}：

E. calculate characteristic value I comprising projection components polarity with amplitude information_{0j_T_P}：

F. 1/2nd of the characteristic value of calculating maximal projection component are threshold value I_th：

G. calculate difference γ of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream_km：

γ_km=I_{0m_T_P}-I_{0k_T_P}

If there is γ_km＞ i_th, then the section is fault section, if there is no γ_km＞ i_th, then the circuit most end section be Fault section.

II, the joint line model based on neutral by arc extinction coil grounding shown in accompanying drawing 3, arrange 5 region 2 of circuit and occur High resistance earthing fault, verifies the validity of above-mentioned algorithm.

(1) there is the high resistance earthing fault of 30 Ω

A. when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then say There is high resistance earthing fault in bright system, electric substation's terminal starts, and selects faulty line 5, and route selection result and faulty line are gone out Mouth zero-sequence current gathered data reports main website；

B., when residual voltage or zero-sequence current Sudden Changing Rate surmount preset threshold, each line feed terminals start, by failure zero sequence Voltage x current gathered data reports main website, shown in such as Fig. 4 (a)；

C. main website receives electric substation's terminal and each monitoring point residual voltage current acquisition data of feeder line, to residual voltage u_b、 The each monitoring point zero-sequence current i of faulty line_0jData are filtered, and extract its transient state component i respectively_{0j_T}、u_{b_T}, such as Fig. 4 (b) institutes Show, then disregard to perfecting line terminal data；

D. faulty line each monitoring point transient zero-sequence current is projected to bus transient zero-sequence voltage, such as Fig. 4 (c) institutes Show.

E. calculate characteristic value I comprising projection components polarity with amplitude information_{0j_T_P}：

I_{01_T_P}=11.971A, I_{02_T_P}=13.134A, I_{03_T_P}=-3.113A, I_{04_T_P}=-1.555A.

F. 1/2nd of the characteristic value of calculating maximal projection component are threshold value I_th：

G. calculate difference γ of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream_km：

γ_km=I_{0m_T_P}-I_{0k_T_P}

γ₁₂=-1.163A, γ₂₃=16.247A, γ₃₄=-1.558A.

H. choose the area of the difference more than threshold value of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream Section 2 is fault section.

F. the section 2 between two monitoring point of reversed polarity is selected to be fault section.

(2) there is the high resistance earthing fault of 1500 Ω

A. when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then say There is high resistance earthing fault in bright system, electric substation's terminal starts, and selects faulty line 5, and route selection result and faulty line are gone out Mouth zero-sequence current gathered data reports main website；

B., when residual voltage or zero-sequence current Sudden Changing Rate surmount preset threshold, each line feed terminals start, by failure zero sequence Voltage x current gathered data reports main website, shown in such as Fig. 5 (a)；

C. main website receives electric substation's terminal and each monitoring point residual voltage current acquisition data of feeder line, to residual voltage u_b、 The each monitoring point zero-sequence current i of faulty line_0jData are filtered, and extract its transient state component i respectively_{0j_T}、u_{b_T}, such as Fig. 5 (b) institutes Show, then disregard to perfecting line terminal data；

D. faulty line each monitoring point transient zero-sequence current is projected to bus transient zero-sequence voltage, such as Fig. 4 (c) institutes Show.

E. calculate characteristic value I comprising projection components polarity with amplitude information_{0j_T_P}：

I_{01_T_P}=0.901A, I_{02_T_P}=1.017A, I_{03_T_P}=-0.101A, I_{04_T_P}=-0.073A.

F. 1/2nd of the characteristic value of calculating maximal projection component are threshold value I_th：

G. calculate difference γ of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream_km：

γ_km=I_{0m_T_P}-I_{0k_T_P}

γ₁₂=-0.116A, γ₂₃=1.118A, γ₃₄=-0.028A.

H. choose the area of the difference more than threshold value of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream Section 2 is fault section.

F. the section 2 between two monitoring point of reversed polarity is selected to be fault section.

The above, is only presently preferred embodiments of the present invention, is not the restriction for making other forms to the present invention, any ripe The technology contents that professional and technical personnel is known possibly also with the disclosure above are changed or are modified as the equivalent reality of equivalent variations Apply example.But it is every without departing from technical solution of the present invention content, above example is made according to the technical spirit of the present invention Any simple modification, equivalent variations and remodeling, still fall within the protection domain of technical solution of the present invention.

Claims (1)

1. this patent proposes that one kind projects component waveform on bus transient voltage based on transient current and compares, it is adaptable to which terminal is supervised The high resistance ground of the small current neutral grounding mode distribution system (there is the section surrounded by three or more monitoring points) on survey line road Fault Locating Method, it is characterised in that：Terminal online acquisition zero-sequence current and residual voltage, when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then illustrate that system occurs high resistance earthing fault, according to the following steps Carry out fault location：

A. when bus residual voltage amplitude is in U_th1＜ U_b＜ U_th2When (general U_th1=15V, U_th2=90V), then illustrate system Generation high resistance earthing fault, electric substation's terminal start, and select faulty line, and will be route selection result and faulty line outlet zero sequence electric Stream gathered data reports main website；

B., when zero mode voltage or zero mould jump-value of current surmount preset threshold, each line feed terminals start, by failure residual voltage Current acquisition data report main website；

C. main website receives electric substation's terminal and each monitoring point residual voltage current acquisition data of feeder line, to residual voltage u_b, fault wire The each monitoring point zero-sequence current i in road_0jData are filtered, and extract its transient state component i respectively_{0j_T}、u_{b_T}, to perfecting line terminal number According to then disregarding；

D. faulty line each monitoring point transient zero-sequence current is projected to bus transient zero-sequence voltage, is calculated according to following formula Projection components i of each monitoring point transient zero-sequence current_{0j_T_P}：

$i_{0j\_T\_P}=\frac{<i_{0j\_T},u_{b\_T}>}{\left|\right|u_{b\_T}|{|}^2}{u}_{b\_T}$

E. calculate characteristic value I comprising projection components polarity with amplitude information_{0j_T_P}：

$I_{0j\_T\_P}=\mathrm{sgn}(<i_{0j\_T},u_{b\_T}>)\sqrt{\frac{1}{T}\left|\right|i_{0j\_T\_P}\left|\right|}$

F. 1/2nd of the characteristic value of calculating maximal projection component are threshold value I_th：

$I_{th}=\frac{1}{2}max\left\{I_{0j\_T\_P}\right\}$

G. calculate difference γ of each monitoring point transient zero-sequence current projection components characteristic value in each section upstream and downstream_km：

γ_km=I_{0m_T_P}-I_{0k_T_P}

If there is γ_km＞ i_th, then the section is fault section, if there is no γ_km＞ i_th, then the circuit most end section is failure Section.