CN103632235A - Improved forward-backward sweep algorithm based power-grid low-voltage platform area line loss information processing method - Google Patents

Abstract

The invention relates to an improved forward-backward sweep algorithm based power-grid low-voltage platform area line loss information processing method. The method includes the following steps: 1) acquiring basic data and operating data of a low-voltage platform area of a power grid; 2) computing load shape factors and circuit structure constants of the low-voltage platform area of the power grid and equivalent current of each node according to the basic data and the operating data; 3) adopting an improved forward-backward sweep algorithm to perform iterative computation to obtain voltage of each node and current of each branch; 4) computing line loss information of the low-voltage platform area of the power grid according to the voltage of each node and the current of each branch. Compared with the prior art, the method has the advantages of less needed data, simplicity in implementation, high information accuracy and the like.

Description

Electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method

Technical field

The present invention relates to a kind of information processing method, especially relate to a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method.

Background technology

Line loss is the abbreviation of electrical network electric energy loss, is that electric energy is transferred to power consumer process from generating plant, the electric energy loss and the loss that in transmission of electricity, power transformation, distribution and marketing links, produce.By the structure of line loss, line loss electric weight can be divided into statistical line losses electric weight, theory wire loss electric weight, management line loss electric weight etc.

Power supply area or a power network are within the given period (day, the moon, season, year), and in transmission of electricity, power transformation, each link of distribution, whole electric weight of institute's loss are called line loss electric weight, abbreviation line loss electric weight or line loss.A part in line loss electric weight, determines although can fall to calculate by reason, or measures with the mark of special measurement line loss, its full dose cannot accurately be learnt.Therefore in the actual motion of power network, line loss electric weight normally obtains according to the delivery of ammeter measuring statistics and the difference of electricity sales amount, is commonly called statistical line losses electric weight.

In statistical line losses electric weight, some be electric energy defeated, become, join process in inevitably, its numerical value has operational factor and device parameter in the corresponding period to determine.Wherein mainly comprise: the Transformer Winding being directly proportional to current squaring and the electric energy loss in transmission line wire; The insulation dielectric loss of the transformer core relevant with working voltage, capacitor and cable and kwh loss (open circuit loss) etc.This part loss of electricity is called " technological attrition electric weight " traditionally, and it can calculate by theory, so be called again theory wire loss electric weight.

Another part of statistical line losses is that it comprises because the reason in management work causes: various watt-hour meter composition errors, while checking meter difference, leak and copy and wrong to miscopy the statistic that calculation causes inaccurate; The electric leakage that charging equipment defective insulation causes, the loss electric weight causing without table electricity consumption and stealing etc.This part electric weight custom is called management line loss electric weight.

As can be seen here, merely rely on statistical line losses, cannot hold exactly power network line loss actual conditions.In order to understand more accurately grid line loss, do line loss management work well, draft and reasonably fall damage measure, carry out theory wire loss calculating accurately and seem particularly important.

In recent decades, along with scientific and technological development, the improving constantly of computer technology, theory wire loss computing method have a great development, and have occurred multiple computing method.According to collecting Data classification, be broadly divided into following two classes: integral point data method and mathematical methods.

Integral point data method adopts Typical Representative day integral point data conventionally, asks for the load shape coefficient of low-voltage distribution transformer low-pressure side head end, and then carries out the calculating of low-voltage distribution network line loss.These class methods mostly are simplifies method of approximation and tidal current computing method.Wherein substitutional resistance method and before push back for method, use the most extensive.

Mathematical methods needs a large amount of historical datas as sample.By adopt specific mathematical method to sample training, analyze, set up suitable mathematical model, thereby form the relational expression between circuit line loss value and characteristic ginseng value.These class methods mostly are regression analysis and intelligent algorithm (neural network is in the majority).Because the method data acquisition amount is large, the order of accuarcy of data has very large relation to the accuracy of mathematical model, and versatility is not good.For different low-voltage distribution networks, due to the difference of line construction and operation conditions, mathematical model can change always, and the fussy degree of calculation and programming constantly rises, and the accuracy of calculating declines, present circumstances, and its development space in low-voltage platform area is little.

Summary of the invention

Object of the present invention is exactly to provide a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method in order to overcome the defect of above-mentioned prior art existence.

Object of the present invention can be achieved through the following technical solutions:

An electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method, comprises the following steps:

1) obtain basic data and the service data of electrical network low-voltage platform area;

2) according to basic data and service data, calculate the load shape coefficient of electrical network low-voltage platform area and the equivalent current of line construction constant and each node;

3) adopt improvement Forward and backward substitution method to carry out iterative computation, draw each node voltage and each branch current;

4) according to each node voltage and each branch current, calculate the line loss information of electrical network low-voltage platform area.

The basic data of electrical network low-voltage platform area comprises topological relation and the wire parameter of electrical network, and the service data of electrical network low-voltage platform area comprises working time, power factor (PF) and supply and distribution.

Step 3) concrete steps that adopt improvement Forward and backward substitution method to carry out iterative computation are:

31) each node voltage of initialization, makes the voltage of each node

the nodes that wherein m is power distribution network, U ₀for initial voltage;

32), from circuit tip one stage load, according to node power, calculate each branch current that flows into frontier node

33) according to each branch current and distribution low-voltage side head end voltage, by iteration, obtain each node voltage and node voltage maximal value modified value

34) decision node voltage max modified value

whether restrain, if branch current is exported in convergence

with each node voltage

if do not restrain, scope step 32) recalculate.

Step 32) in, the computing formula of each branch current is:

In formula:

for the branch current between node i and j;

load current for node j;

for the branch current with node headed by node j, when frontier node that node j is network, p _l,j-jQ _{l, j}for node j load power conjugation;

voltage conjugation for node j.

Step 33) node voltage in

computing formula be:

$\mathrm{\Δ}{\stackrel{g}{U}}_i-\left(\frac{{\stackrel{g}{U}}_j-{\stackrel{g}{U}}_i}{{\stackrel{*}{U}}_i}\right)\mathrm{\Δ}{\stackrel{*}{U}}_i={\stackrel{g}{U}}_j+\mathrm{\Δ}{\stackrel{g}{U}}_j-{\stackrel{g}{U}}_i-Z_{\mathrm{ji}}{\stackrel{g}{I}}_{\mathrm{ji}}$

The iterative formula of subsequent node voltage is:

$\begin{array}{c}\mathrm{\Δ}{\stackrel{g}{U}}_i^{(t+1)}-\left(\frac{{\stackrel{g}{U}}_j^{\left(t\right)}-{\stackrel{g}{U}}_i^{\left(t\right)}}{{\stackrel{*}{U}}_i^{\left(t\right)}}\right)\mathrm{\Δ}{\stackrel{*}{U}}_i^{(t+1)}={\stackrel{g}{U}}_j^{(t+1)}-{\stackrel{g}{U}}_i^{\left(t\right)}-Z_{\mathrm{ji}}{\stackrel{g}{I}}_{\mathrm{ji}}^{\left(t\right)}\\ {\stackrel{g}{U}}_i^{(t+1)}={\stackrel{g}{U}}_i^{\left(t\right)}+\mathrm{\Δ}{\stackrel{g}{U}}_i^{(t+1)}\end{array}$

Node voltage maximal value modified value

computing formula be:

In formula, voltage for father node j;

voltage for child node i;

impedance for node i and j branch road; T is iterations.

Step 34) in, the criterion of convergence is: wherein ε is the threshold value of setting; If exist

be judged to be convergence.

Compared with prior art, the present invention has the following advantages:

One, calculating desired data is less, and is easy to obtain;

Two, computational accuracy is high;

Three, algorithm versatility is high;

Four, algorithm improves the advantages such as potentiality are large.

Accompanying drawing explanation

Fig. 1 is process flow diagram of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

Embodiment

As shown in Figure 1, a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method, comprises the following steps:

Step 1, the basic data of obtaining electrical network low-voltage platform area and service data, wherein, the basic data of electrical network low-voltage platform area comprises topological relation and the wire parameter of electrical network, the service data of electrical network low-voltage platform area comprises working time, power factor (PF) and supply and distribution.

Step 2, according to basic data and service data, calculate the load shape coefficient of electrical network low-voltage platform area and the equivalent current of line construction constant and each node.

Step 3, employing improve Forward and backward substitution method and carry out iterative computation, draw each node voltage and each branch current, and concrete steps are:

3-1, each node voltage of initialization, make the voltage of each node

the nodes that wherein m is power distribution network, U ₀for initial voltage;

3-2, from circuit tip one stage load, according to node power, calculate to flow into each branch current of frontier node

specific formula for calculation is:

In formula:

for the branch current between node i and j;

load current for node j;

for the branch current with node headed by node j, when frontier node that node j is network,

p _{l, j}-jQ _l,jfor node j load power conjugation;

voltage conjugation for node j;

3-3, according to each branch current and distribution low-voltage side head end voltage, by iteration, obtain each node voltage and node voltage maximal value modified value wherein, middle node voltage

computing formula be:

$\mathrm{\Δ}{\stackrel{g}{U}}_i-\left(\frac{{\stackrel{g}{U}}_j-{\stackrel{g}{U}}_i}{{\stackrel{*}{U}}_i}\right)\mathrm{\Δ}{\stackrel{*}{U}}_i={\stackrel{g}{U}}_j+\mathrm{\Δ}{\stackrel{g}{U}}_j-{\stackrel{g}{U}}_i-Z_{\mathrm{ji}}{\stackrel{g}{I}}_{\mathrm{ji}}$

The iterative formula of subsequent node voltage is:

$\begin{array}{c}\mathrm{\Δ}{\stackrel{g}{U}}_i^{(t+1)}-\left(\frac{{\stackrel{g}{U}}_j^{\left(t\right)}-{\stackrel{g}{U}}_i^{\left(t\right)}}{{\stackrel{*}{U}}_i^{\left(t\right)}}\right)\mathrm{\Δ}{\stackrel{*}{U}}_i^{(t+1)}={\stackrel{g}{U}}_j^{(t+1)}-{\stackrel{g}{U}}_i^{\left(t\right)}-Z_{\mathrm{ji}}{\stackrel{g}{I}}_{\mathrm{ji}}^{\left(t\right)}\\ {\stackrel{g}{U}}_i^{(t+1)}={\stackrel{g}{U}}_i^{\left(t\right)}+\mathrm{\Δ}{\stackrel{g}{U}}_i^{(t+1)}\end{array}$

Node voltage maximal value modified value

computing formula be:

In formula,

voltage for father node j; voltage for child node i;

impedance for node i and j branch road; T is iterations.

3-4, decision node voltage max modified value whether restrain, if branch current is exported in convergence

with each node voltage

if do not restrain, scope step 32) recalculate.Wherein, the criterion of convergence is:

wherein ε is the threshold value of setting; If exist

be judged to be convergence.

Claims (6)

1. the electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method, is characterized in that, comprises the following steps:

1) obtain basic data and the service data of electrical network low-voltage platform area;

2) according to basic data and service data, calculate the load shape coefficient of electrical network low-voltage platform area and the equivalent current of line construction constant and each node;

3) adopt improvement Forward and backward substitution method to carry out iterative computation, draw each node voltage and each branch current;

4) according to each node voltage and each branch current, calculate the line loss information of electrical network low-voltage platform area.

2. a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method according to claim 1, it is characterized in that, the basic data of electrical network low-voltage platform area comprises topological relation and the wire parameter of electrical network, and the service data of electrical network low-voltage platform area comprises working time, power factor (PF) and supply and distribution.

3. a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method according to claim 1, is characterized in that step 3) adopt and improve the concrete steps that Forward and backward substitution method carries out iterative computation and be:

31) each node voltage of initialization, makes the voltage of each node

the nodes that wherein m is power distribution network, U ₀for initial voltage;

32), from circuit tip one stage load, according to node power, calculate each branch current that flows into frontier node

33) according to each branch current and distribution low-voltage side head end voltage, by iteration, obtain each node voltage and node voltage maximal value modified value

34) decision node voltage max modified value

whether restrain, if branch current is exported in convergence

with each node voltage

if do not restrain, scope step 32) recalculate.

4. a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method according to claim 3, is characterized in that step 32) in the computing formula of each branch current be:

In formula:

for the branch current between node i and j;

load current for node j; for the branch current with node headed by node j, when frontier node that node j is network,

p _{l, j}-jQ _{l, j}for node j load power conjugation;

voltage conjugation for node j.

5. a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method according to claim 3, is characterized in that step 33) middle node voltage

computing formula be:

$\mathrm{\Δ}{\stackrel{g}{U}}_i-\left(\frac{{\stackrel{g}{U}}_j-{\stackrel{g}{U}}_i}{{\stackrel{*}{U}}_i}\right)\mathrm{\Δ}{\stackrel{*}{U}}_i={\stackrel{g}{U}}_j+\mathrm{\Δ}{\stackrel{g}{U}}_j-{\stackrel{g}{U}}_i-Z_{\mathrm{ji}}{\stackrel{g}{I}}_{\mathrm{ji}}$

The iterative formula of subsequent node voltage is:

$\begin{array}{c}\mathrm{\Δ}{\stackrel{g}{U}}_i^{(t+1)}-\left(\frac{{\stackrel{g}{U}}_j^{\left(t\right)}-{\stackrel{g}{U}}_i^{\left(t\right)}}{{\stackrel{*}{U}}_i^{\left(t\right)}}\right)\mathrm{\Δ}{\stackrel{*}{U}}_i^{(t+1)}={\stackrel{g}{U}}_j^{(t+1)}-{\stackrel{g}{U}}_i^{\left(t\right)}-Z_{\mathrm{ji}}{\stackrel{g}{I}}_{\mathrm{ji}}^{\left(t\right)}\\ {\stackrel{g}{U}}_i^{(t+1)}={\stackrel{g}{U}}_i^{\left(t\right)}+\mathrm{\Δ}{\stackrel{g}{U}}_i^{(t+1)}\end{array}$

Node voltage maximal value modified value

computing formula be:

In formula,

voltage for father node j;

voltage for child node i;

impedance for node i and j branch road; T is iterations.

6. a kind of electrical network low-voltage platform area line loss information processing method based on improving Forward and backward substitution method according to claim 3, is characterized in that step 34) in the criterion of convergence be:

wherein ε is the threshold value of setting; If exist

be judged to be convergence.

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