CN109596889A

CN109596889A - A kind of low-voltage network line impedance on-line measurement system and method

Info

Publication number: CN109596889A
Application number: CN201910025312.0A
Authority: CN
Inventors: 范洁; 陈霄; 李新家; 王黎明; 严永辉; 喻伟; 熊政; 李平; 管诗骈; 赵勇; 刘飞; 刘述波; 徐博; 戚文君
Original assignee: State Grid Corp of China SGCC; State Grid Jiangsu Electric Power Co Ltd; Jiangsu Fangtian Power Technology Co Ltd
Current assignee: State Grid Corp of China SGCC; State Grid Jiangsu Electric Power Co Ltd; Jiangsu Fangtian Power Technology Co Ltd
Priority date: 2019-01-10
Filing date: 2019-01-10
Publication date: 2019-04-09

Abstract

A low-voltage distribution network line impedance online measurement system and method. The system is mainly composed of a main station platform and a number of acquisition terminals. The acquisition terminal is composed of main components such as a main processor, a metering chip, a memory chip, a clock chip, and a GPRS communication module. Under the control of the main processor, the clock rhythm is first obtained through the clock chip, and then the basic power information such as voltage and current at each node of the distribution network is obtained through the measurement chip, and recorded in the memory chip, and then the processor uses the relevant algorithm to calculate and obtain the circuit. Impedance parameter value, and finally transmit the data to the main station platform through the GPRS communication module. The invention proposes an economically and technically feasible low-voltage distribution network line impedance online measurement system and method, which has important reference significance for grid access to new power equipment and system evaluation, and line fault prediction.

Description

A kind of low-voltage network line impedance on-line measurement system and method

Technical field

The invention belongs to low-voltage network line impedance fields of measurement, and in particular to a kind of low-voltage network line impedance exists Line measuring system and method.

Background technique

Nerve endings of the low-voltage network as entire bulk power grid, couples huge numbers of families, and operating status directly affects Power supply quality, the production of client, life are brought and are directly affected.Wherein, low-voltage network line impedance parameter is always electricity The key issues for netting research, accessing new power equipment and system evaluation and line fault anticipation to power grid has important ginseng Examine meaning.

Summary of the invention

The present invention aiming at the shortcomings in the prior art, provides a kind of low-voltage network line impedance on-line measurement system and side Method.

To achieve the above object, the invention adopts the following technical scheme:

A kind of low-voltage network line impedance on-line measurement system characterized by comprising main website platform and several acquisitions Terminal；The basic power information of the acquisition terminal measurement low-voltage network corresponding line, calculates line impedance parameter value, then Main website platform is sent to by GPRS network.

To optimize above-mentioned technical proposal, the concrete measure taken further include:

The acquisition terminal includes primary processor, metering chip, storage chip, clock chip, GPRS communication module, in master Under the control of processor, timeticks are obtained by clock chip first, it is each then to measure acquisition power distribution network by metering chip Basic power information at node, and it is recorded in storage chip, then calculate by primary processor and obtain line impedance parameter value, most Main website platform is transferred data to by GPRS communication module afterwards；Wherein, the basic power information includes voltage and current.

Furthermore, it is also proposed that a kind of measurement side using low-voltage network line impedance on-line measurement system as described above Method, which is characterized in that on acquisition terminal after electricity operation, with " day " for the period, execute following steps:

Step 1: resetting constant M, constant Rt, constant Sn；

Step 2: according to fixed intervals T, measurement obtains current voltage Uj, electric current Ij, wherein 1≤j≤N, N=24*60* 60/T；

Step 3: voltage Ui, the electric current Ii recorded according to previous cycle calculates voltage change Δ Ui=| Uj-Ui |, electricity Flow changing value Δ Ii=| Ij-Ii |, wherein i=j-1,0≤i≤N-1；

Step 4: route real-time impedance value Ri is calculated, if 0 < Δ Ui < UCLMT and Δ Ii ≠ 0, Ri=Δ Ui/ Δ Ii, M 1, the Rt that adds up adds up Ri, otherwise Ri=0, and wherein UCLMT indicates voltage jump exception limit value；

Step 5: judging whether the same day terminates, continue step 2 if being not finished, otherwise carry out step 6；

Step 6: calculatingWherein Ri ≠ 0, Ravg=Rt/M, Ravg indicate route Impedance mean value；

Step 7: line impedance real value R0, R1, R2 ... Rx of the statistics same day all measurements are in confidence intervalInterior quantity is K, wherein x=N-1；

Step 8: calculating line impedance parameter valueWherein Ri is in confidence intervalIt is interior；

Step 9: by GPRS module, same day line impedance parameter value RL being sent to main website platform.

T value 5 seconds, UCLMT value 4.0V.

The beneficial effects of the present invention are: proposing a kind of feasible low-voltage network line impedance on-line measurement of economic technology System and method, accessing new power equipment and system evaluation and line fault anticipation to power grid has important references meaning.

Detailed description of the invention

Fig. 1 is the whole composition schematic diagram of system.

Fig. 2 is acquisition terminal composition block diagram.

Fig. 3 is the flow diagram of method.

Specific embodiment

In conjunction with the accompanying drawings, the present invention is further explained in detail.

System integrally forms as shown in Figure 1, being mainly made of main website platform and several acquisition terminals, and acquisition terminal measurement is low The basic informations such as power grid corresponding line voltage and current are press-fitted, calculate line impedance parameter value, then send to by GPRS network Main website platform.

For acquisition terminal as key equipment, composition block diagram is as shown in Figure 2.Acquisition terminal by primary processor, metering chip, The main components such as storage chip, clock chip, GPRS communication module composition passes through clock core under primary processor control first Piece obtains timeticks, is then measured by metering chip and obtains the basic power information such as each voltage at node electric current of power distribution network, And it is recorded in storage chip, then calculate by processor using related algorithm and obtain line impedance parameter value, finally by GPRS Communication module transfers data to main website platform.

Measurement method is as follows:

On acquisition terminal after electricity operation, with " day " for the period, following steps are executed:

Step 1: resetting constant M, constant Rt, constant Sn；

Step 2: according to fixed intervals T, measurement obtains current voltage Uj, electric current Ij, wherein 1≤j≤N, N=24*60* 60/T, T value 5 seconds；

Step 3: voltage Ui, the electric current Ii recorded according to previous cycle, calculating voltage change Δ Ui (Δ Ui=| Uj-Ui |), current variation value Δ Ii (Δ Ii=| Ij-Ii |), wherein i=j-1,0≤i≤N-1；

Step 4: route real-time impedance value Ri is calculated, if 0 < Δ Ui < UCLMT and Δ Ii ≠ 0, Ri=Δ Ui/ Δ Ii, M 1, the Rt that adds up adds up Ri, otherwise Ri=0, and wherein UCLMT indicates voltage jump exception limit value, value 4.0V；

If Δ Ui > UCLMT, system thinks that this measurement point is power distribution network exception overshoot current or other abnormal generations, meter Automatic rejection falls this measurement point when calculation；

Line impedance number of measurement values is more, and Normal Distribution Characteristics can integrally be presented, and is calculated using normal distribution correlation formula, Further obtain effective sample；

The above is only the preferred embodiment of the present invention, protection scope of the present invention is not limited merely to above-described embodiment, All technical solutions belonged under thinking of the present invention all belong to the scope of protection of the present invention.It should be pointed out that for the art For those of ordinary skill, several improvements and modifications without departing from the principles of the present invention should be regarded as protection of the invention Range.

Claims

1. A low-voltage distribution network line impedance online measurement system, characterized in that it comprises: a main station platform and several acquisition terminals; the acquisition terminal measures the basic power information of the corresponding lines of the low-voltage distribution network, and calculates the line impedance parameter value , and then transmitted to the main station platform through the GPRS network.

2. A low-voltage distribution network line impedance online measurement system as claimed in claim 1, characterized in that: the acquisition terminal comprises a main processor, a metering chip, a memory chip, a clock chip, and a GPRS communication module. Under the control of the controller, the clock tick is first obtained through the clock chip, and then the basic power information at each node of the distribution network is obtained through the measurement chip, and recorded in the memory chip, and then the line impedance parameter value is obtained through the calculation of the main processor. The GPRS communication module transmits data to the main station platform; wherein, the basic power information includes voltage and current.

3. a measurement method using the low-voltage distribution network line impedance online measurement system as claimed in claim 1 or 2, is characterized in that, after the collection terminal is powered on and runs, with "day" as a cycle, the following steps are performed:

Step 1: Clear constant M, constant Rt, and constant Sn;

Step 2: According to the fixed interval T, measure and obtain the current voltage Uj and current Ij, where 1≤j≤N, N=24*60*60/T;

Step 3: Calculate the voltage change value ΔUi=|Uj-Ui| and the current change value ΔIi=|Ij-Ii| according to the voltage Ui and current Ii recorded in the previous cycle, where i=j-1, 0≤i≤N -1;

Step 4: Calculate the real-time impedance value Ri of the line. If 0<ΔUi<UCLMT and ΔIi≠0, then Ri=ΔUi/ΔIi, M is accumulated by 1, and Rt is accumulated by Ri, otherwise Ri=0, where UCLMT represents the abnormal voltage mutation limit;

Step 5: Determine whether the day ends, if not, proceed to Step 2, otherwise, proceed to Step 6;

Step 6: Calculate Where Ri≠0, Ravg=Rt/M, Ravg represents the mean value of line impedance;

Step 7: Count all measured line impedance real-time values RO, R1, R2...Rx in the confidence interval on the day The inner quantity is K, where x=N-1;

Step 8: Calculate the line impedance parameter value where Ri is in the confidence interval Inside;

Step 9: The line impedance parameter value RL of the day is transmitted to the main station platform through the GPRS module.

4. The measuring method according to claim 3, characterized in that: T takes a value of 5 seconds, and UCLMT takes a value of 4.0V.