CN104376505A - Method for evaluating running reliability of power distribution network in power system - Google Patents

Abstract

The invention relates to a method for evaluating running reliability of a power distribution network in a power system, and belongs to the technical field of reliability analysis of the power system. According to the method, health indexes in unit elements in the power distribution network are taken as the basis, and the health index of the system is evaluated through combination of conversion calculation of the health indexes and the health index probability form and the connection manner of the health indexes and the health index probability. According to the analysis result, repair cycle of the equipment is reasonably determined; repair cost of power grid running and power equipment is reduced, and running reliability of the equipment is improved. The health state of the power distribution network is evaluated through the index form of numerical values from one to ten, and the theoretical basis is provided for reliable running and repair plan making of the power distribution network, so that planning, operation, maintenance and the management level of the power distribution network can be further improved, and the asset management system of the power distribution network is perfected.

Description

A kind of operation reliability evaluation method of power distribution network in electric system

Technical field

The present invention relates to the operation reliability evaluation method of power distribution network in a kind of electric system, belong to Power System Reliability Analysis technical field.

Background technology

Developed countries electric load just enters the phase of growing steadily substantially from the eighties in 20th century, and electrical network scale is substantially fixing, how to have entered and to be in the full-fledged stage.The development of power distribution network and management are more pay close attention to operational reliability and economy, advance intellectualized technology, promote service quality.EA company of Britain is the demand adapting to the aging peak of Britain's large-scale equipment, develop a set of " Risk Management System based on condition assessment of power grid ", nowadays this system has been employed for all Utilities Electric Co.s of Britain, and applies with succeeding in countries such as Canada, the U.S., Australia, Malaysia and Singapore.

Since State Grid Corporation of China of China carried out whole-life cycle fee system from 2008 comprehensively, progressively started the account, repair based on condition of component data, the repair based on condition of component directive/guide that form UHV (ultra-high voltage) and high-tension apparatus, Diagnostic Examination And Repair of Electric Power Facilities is also progressively expanded from UHV (ultra-high voltage) and high pressure field to field of distribution network.

But system for distribution network of power shortcoming is numerous, be in particular in following some:

One, equipment kind is numerous and diverse, manufacture that threshold is low and manufacturer is numerous, have a large capacity and a wide range;

Its two, master data shortcoming or inaccurate, lack long-term data accumulation;

Its three, the level of informatization is not high, cannot realize the direct collection of field data, statistics and analysis;

Its four, financial management lean degree is not high, not yet reaches the interlock of wealth card thing;

Its five, multi-source information isolated island poor compatibility;

Its six, automaticity is low, and detection level such as to be left in the basket because single equipment cost is relatively low at the shortcoming, causes traditional way to manage can not adapt to the needs developed under the new situation.

By the end of at present, in the research work that the different department of power distribution network carries out, be mostly also only confined to the research to aspects such as power distribution network asset management feature, means and Informational support.Existing part research at present in controller switching equipment rank health index, but still without the health status research of power distribution network network level.

Summary of the invention

The object of the invention is the operation reliability evaluation method proposing power distribution network in a kind of electric system, in power distribution network based on each monolithic element health index, by the conversion of health index and health index Probability Forms, in conjunction with its connected mode, Study system health index is given a mark, and according to its analysis result, rationally determine the time between overhauls(TBO) of equipment, reduce operation of power networks and electric power apparatus examination expense and improve equipment operational reliability.

The modeling method of power distribution network health index in the electric system that the present invention proposes, comprises the following steps:

If system for distribution network of power comprises a main feeder and multilevel branch feeder line, multilevel branch feeder line has many respectively, every bar branch feeder is connected with multiple element, and equivalent to upper level branch feeder successively from power distribution network most end level branch feeder, detailed process comprises the steps:

(1) the health index HI of all elements in power distribution network is calculated _ij, hI _ijbeing the health index value of i-th grade of jth element, is the Arbitrary Digit between 0 to 10.

Wherein, HI ₀for health index when this element dispatches from the factory, general value is 0.5; E is natural logarithm, T _ijfor element working time, can obtain from power distribution network data center; B is ageing equipment index, and when it is generally acknowledged that equipment life stops, health index is 6.5, and equipment runs time limit T and can be dispatched from the factory in parameter by equipment and obtain, and substitutes into above formula, 6.5=0.5 × e ^{b × T}, therefrom can solve B;

(2) each element health index on power distribution network most end level branch feeder is converted into Probability Forms r by following formula _ij:

$r_{\mathrm{ij}}={1-e}^{{-\left(\frac{{\mathrm{HI}}_{\mathrm{ij}}-10}{{\mathrm{HI}}_{\mathrm{ij}}}\right)}^2}$

Wherein, e is natural logarithm;

(3) utilize the Series system of fail-safe analysis, calculate the equivalent health index Probability Forms r of most end level branch feeder _i:

$r_i=\underset{j\∈M}{\mathrm{\Π}}{r}_{\mathrm{ij}}$

Wherein, M is M article of branch feeder in power distribution network all most end levels branch feeder,

(4) obtain i-th grade of branch feeder of above-mentioned steps (3) is as an element, be connected to (i-1) level branch feeder, repeat step (2) and step (3), obtain the equivalent health index Probability Forms of (i-1) level branch feeder;

(5) repeat above-mentioned steps (2), (3), (4), until arrive main feeder, obtain the equivalent health index Probability Forms r of the main feed circuit of the element that cascade connects ₁;

(6) by following formula, by above-mentioned steps (5) equivalent health index Probability Forms r ₁be converted to health index HI _always:

With this health index HI _alwaysas the foundation of the operation reliability evaluation of system for distribution network of power.

The modeling method of power distribution network health index in the electric system that the present invention proposes, its advantage is:

The inventive method is for the present situation lacked in current electric system power distribution network network health performance appraisal procedure, topological structure is numerous and diverse, to comprise the numerous power distribution network of device equivalent layer by layer, finally forms a simple cascaded structure model.Simultaneously, consider the shortcoming that facility level health index cannot participate in cascaded structure network analysis, propose the conversion calculations formula of a kind of health index and health index Probability Forms, to be used in the fail-safe analysis of electric system by connecting less equipment health index in network each other easily, both consider the network equipment and run service condition, combine network topology structure again, and result of calculation and the actual conditions goodness of fit higher, make electric system can evaluate power distribution network health status with the numerical indication form of 0 to 10, the reliability service and the turnaround plan formulation that can be power distribution network are provided fundamental basis.Thus promote distribution network planning, O&M and management level further, improve power distribution network asset management system.

Accompanying drawing explanation

Fig. 1 is the simple power distribution system network structural drawing that the inventive method relates to.

Fig. 2 is the Equivalent Simplification schematic diagram of the power distribution network most end level branch feeder in the inventive method.

In Fig. 1 and Fig. 2,1 is main feeder, and 2 is one-level branch feeders, and 3 is secondary branch feeders.

Embodiment

Power distribution network is made up of main feeder and branch feeder and the element that is connected thereof often, what the inventive method related to is the system for distribution network of power comprising a main feeder and many branch feeders, its structure as shown in Figure 1, first, search for by main feeder 1, by the branch feeder on the main feeder that searches, as the one-level branch feeder 2 in Fig. 1 and secondary branch feeder 3 and the element that is connected thereof (comprise disconnector, section switch, fuse, branch line etc.) be divided into same layer, find branch feeder simultaneously and whether also comprise subordinate's branch feeder, network layer statistics is obtained by searching for layer by layer.

The modeling method of power distribution network health index in the electric system that the present invention proposes, comprises the following steps:

If system for distribution network of power comprises a main feeder and multilevel branch feeder line, multilevel branch feeder line has many respectively, every bar branch feeder is connected with multiple element, and equivalent to upper level branch feeder successively from power distribution network most end level branch feeder, detailed process comprises the steps:

(1) health index of all elements in power distribution network is calculated hI _ijbeing the health index value of i-th grade of jth element, is the Arbitrary Digit between 0 to 10.

Wherein, HI ₀for health index when this element dispatches from the factory, general value is 0.5; E is natural logarithm, T _ijfor element working time, can obtain from power distribution network data center; B is ageing equipment index, and when it is generally acknowledged that equipment life stops, health index is 6.5, and equipment runs time limit T and can be dispatched from the factory in parameter by equipment and obtain, and substitutes into above formula, 6.5=0.5 × e ^{b × T}, therefrom can solve B;

(2) each element health index on power distribution network most end level branch feeder is converted into Probability Forms r by following formula _ij:

$r_{\mathrm{ij}}={1-e}^{-{\left(\frac{{\mathrm{HI}}_{\mathrm{ij}}-10}{{\mathrm{HI}}_{\mathrm{ij}}}\right)}^2}$

Wherein, e is natural logarithm;

(3) utilize the Series system of fail-safe analysis, calculate the equivalent health index Probability Forms r of most end level branch feeder _i:

$r_i=\underset{j\∈M}{\mathrm{\Π}}{r}_{\mathrm{ij}}$

Wherein, M is M article of branch feeder in power distribution network all most end levels branch feeder,

(4) obtain i-th grade of branch feeder of above-mentioned steps (3) is as an element, be connected to (i-1) level branch feeder, repeat step (2) and step (3), obtain the equivalent health index Probability Forms of (i-1) level branch feeder, as shown in Figure 2;

(5) repeat above-mentioned steps (2), (3), (4), until arrive main feeder, obtain the equivalent health index Probability Forms r of the main feed circuit of the element that cascade connects ₁;

(6) by following formula, by above-mentioned steps (5) equivalent health index Probability Forms r ₁be converted to health index HI _always:

With this health index HI _alwaysas the foundation of the operation reliability evaluation of system for distribution network of power.In general, HI _alwaysnumerical value is less, and the operational reliability degree representing system for distribution network of power is higher.

Claims (1)

1. the operation reliability evaluation method of power distribution network in electric system, is characterized in that the method comprises the following steps:

If system for distribution network of power comprises a main feeder and multilevel branch feeder line, multilevel branch feeder line has many respectively, every bar branch feeder is connected with multiple element, and equivalent to upper level branch feeder successively from power distribution network most end level branch feeder, detailed process comprises the steps:

(1) the health index HI of all elements in power distribution network is calculated _ij, hI _ijbeing the health index value of i-th grade of jth element, is the Arbitrary Digit between 0 to 10.

Wherein, HI ₀for health index when this element dispatches from the factory, general value is 0.5; E is natural logarithm, T _ijfor element working time, obtain from power distribution network data center, B is ageing equipment index, and when equipment life stops, health index is 6.5, and equipment runs time limit T and dispatched from the factory in parameter by equipment and obtain, and substitutes into above formula, i.e. 6.5=0.5 × e ^{b × T}, therefrom solve B;

(2) each element health index on power distribution network most end level branch feeder is converted into Probability Forms r by following formula _ij:

$r_{\mathrm{ij}}=1-e^{-{\left(\frac{{\mathrm{HI}}_{\mathrm{ij}}-10}{{\mathrm{HI}}_{\mathrm{ij}}}\right)}^2}$

Wherein, e is natural logarithm;

(3) utilize the Series system of fail-safe analysis, calculate the equivalent health index Probability Forms r of most end level branch feeder _i:

$r_i=\underset{j\∈M}{\mathrm{\Π}}{r}_{\mathrm{ij}}$

Wherein, M is M article of branch feeder in power distribution network all most end levels branch feeder,

(4) the i-th grade of branch feeder obtained using above-mentioned steps (3) is as an element, be connected to (i-1) level branch feeder, repeat step (2) and step (3), obtain the equivalent health index Probability Forms of (i-1) level branch feeder;

(5) repeat above-mentioned steps (2), (3), (4), until arrive main feeder, obtain the equivalent health index Probability Forms r of the main feed circuit of the element that cascade connects ₁;

(6) by following formula, by above-mentioned steps (5) equivalent health index Probability Forms r ₁be converted to health index HI _always:

With this health index HI _alwaysas the foundation of the operation reliability evaluation of system for distribution network of power.