CN105868830B

CN105868830B - Method for determining maintenance sequence of multiple transformers

Info

Publication number: CN105868830B
Application number: CN201610170099.9A
Authority: CN
Inventors: 阎春雨; 毕建刚; 王峰; 张博文; 朱太云; 叶剑涛; 程登峰; 王刘芳; 赵常威; 陈忠; 刘航; 周立玮; 刘玉; 王有元
Original assignee: Chongqing University; State Grid Corp of China SGCC; China Electric Power Research Institute Co Ltd CEPRI; Electric Power Research Institute of State Grid Anhui Electric Power Co Ltd
Current assignee: Chongqing University; State Grid Corp of China SGCC; China Electric Power Research Institute Co Ltd CEPRI; Electric Power Research Institute of State Grid Anhui Electric Power Co Ltd
Priority date: 2016-03-23
Filing date: 2016-03-23
Publication date: 2020-12-22
Anticipated expiration: 2036-03-23
Also published as: CN105868830A

Abstract

The invention discloses a method for determining the maintenance sequence of a plurality of transformers, which comprises the following steps: 1) collecting the state grade, defect type, maintenance mode, maintenance cost F and current fault rate of the transformer to be detected in a certain area as input parameters; 2) determining working life rollback factors of different overhaul modes, and calculating the fault rate of the transformer to be inspected before and after overhaul by using a working life rollback method; 3) the overhaul cost E for reducing the unit fault rate after the transformer is overhauled is used as an evaluation index, and the overhaul cost E required by the ith to-be-inspected transformer for reducing the unit fault rate is calculated_iAccording to E_iAnd arranging the maintenance sequence of the transformer to be detected from small to large. The invention determines the maintenance measurement by utilizing the importance of different transformers in the power system, the severity of the defects and the urgency of the maintenance work, can arrange the more important transformers with more serious defects to be maintained in time, and improves the maintenance efficiency. The invention provides beneficial reference for the operation and maintenance strategy formulation of the power equipment.

Description

Method for determining maintenance sequence of multiple transformers

Technical Field

The invention relates to the field of power equipment state maintenance, in particular to a method for determining a maintenance sequence of a plurality of transformers.

Background

The power transformer is the core of energy conversion and transmission in the power grid and is one of the most important and critical devices in the power grid. The failure of the transformer during operation can cause damage to equipment and interruption of the power supply of the power system, resulting in huge power outage losses. The transformer with faults or defects is maintained in time, so that the fault rate of the transformer can be effectively reduced, and the method has important significance for ensuring the power supply reliability of a power system.

In the traditional maintenance mode taking the health state of equipment as the center, all transformers are treated as the same thing, namely, the maintenance work is immediately carried out after the equipment has defects. The mode can reduce the failure rate of the equipment to a certain extent and ensure the power supply reliability of the power system. But such a way of servicing ignores the importance of different transformers in the power system, the severity of the defect and the urgency of the servicing work. Along with the development of a power system, the number of transformers is increased, and when the number of transformers to be detected is large, heavy maintenance work can be caused by the method for establishing the maintenance strategy, and adverse effects such as untimely maintenance of important equipment can be caused. In addition, the method often cannot arrange the overhaul of the transformer with higher importance and serious defects in time, so that the overhaul efficiency cannot be effectively improved.

Disclosure of Invention

The invention aims to solve the problem that the maintenance strategy taking the health state of equipment as the center cannot arrange the priority maintenance of the equipment with high importance, and provides a method for determining the maintenance sequence of a plurality of transformers, and in order to realize the aim, the invention adopts the following technical scheme:

the method for determining the maintenance sequence of the plurality of transformers collects parameter data of n transformers to be detected in a certain area, takes maintenance cost E for reducing unit fault rate after the transformers are maintained as an evaluation index, calculates and compares the E values of the different transformers to be detected, and determines the maintenance sequence of the power equipment according to the sequence of the E from small to large.

The specific maintenance sequence determining method comprises the following steps:

1) collecting the maintenance cost F of the state grade, the defect type, the maintenance mode and the j maintenance mode of n transformers to be detected in a certain area_jAnd failure rate lambda before equipment overhaul₀(t) as input parameters; the j-type maintenance mode comprises A type, B type, C type and D type. The overhaul costs include the payroll expenses of the overhaul personnel, the purchase of overhaul tools, the repair of faults, and the like. The overhaul cost can be obtained by checking equipment ledgers, overhaul records and the like or by estimating by using an economics method.

2) Obtaining service life rollback factors of different overhaul modes according to previous overhaul results of equipment, and calculating fault rate lambda before and after overhaul of transformer to be inspected by using service life rollback method(t)₁：

In the formula, alpha is a scale parameter; beta is a shape parameter; c is a constant; and t is the service age of the equipment.

The condition maintenance can recover the function of the equipment lost due to the fault and can also improve the overall performance of the equipment. After the equipment is overhauled, the failure rate is reduced as if the life of the equipment is pushed forward by a certain amount. Under different maintenance schemes, the failure rate reduction degree of the equipment is different. To quantitatively characterize the change in equipment failure rate from service, the present invention introduces a service life rollback method to calculate the post-service failure rate of the equipment.

3) The overhaul cost E for reducing the unit failure rate after the overhaul of the transformer is taken as an evaluation index; calculating the required maintenance cost E of the ith to-be-detected transformer for reducing the unit fault rate by the formula (2)_i。

In the formula, λ_i0(t) is the fault rate before the i-th equipment to be inspected is overhauled, lambda_i1(t) calculating the fault rate after the overhaul of the ith transformer to be inspected, F, for the service life rollback method_ijAnd (3) the maintenance cost of the ith to-be-detected equipment in the j-class maintenance mode is i ═ 1, 2.

4) According to E_iArranging n overhauling sequences of the transformers to be detected in sequence.

The invention has the beneficial effects that: the invention provides a method for determining the maintenance sequence of a plurality of transformers, which determines maintenance measurement by utilizing the importance of different transformers in a power system, the severity of defects and the urgency degree of maintenance work, can timely arrange that the transformers with more important and more serious defects are maintained first, and improves the maintenance efficiency of equipment.

Drawings

FIG. 1 is a system schematic diagram of a method for determining the maintenance sequence of a plurality of transformers;

fig. 2 is a schematic drawing of the service life retraction of an appliance.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and examples, but it should not be construed that the scope of the above-described subject matter is limited to the examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.

With reference to fig. 1: the method for determining the maintenance sequence of the plurality of transformers comprises the steps of collecting parameter data of all transformers to be detected by taking maintenance cost E for reducing unit fault rate after the transformers are maintained as an evaluation index, calculating and comparing the values of the maintenance cost E for reducing the unit fault rate after different transformers to be detected are maintained, and obtaining the maintenance sequence of equipment.

1) there are 28 110kV transformers in a certain area, and 5 transformers to be overhauled. The state results of 5 devices to be detected, the failure rate before device maintenance, the defect parts and the maintenance mode are shown in table 1.

TABLE 1 evaluation results of State and failure Rate of device to be tested

Number of transformer to be detected	Failure rate before equipment overhaul	Location of failure	Maintenance mode	F_ijMaintenance expense (Wanyuan)
					11	0.0465	Body	C	10
14	0.0465	Sleeve pipe	B	20
					15	0.0722	Body	A	50
19	0.0722	Sleeve pipe	B	20
					27	0.1504	Body	A	50

2) Obtaining service life rollback factors of different overhaul modes according to previous overhaul results of the equipment, and referring to table 2; and calculating the fault rate before and after the overhaul of the transformer to be inspected by a working life rollback method.

Making statistics on the working life and fault rate of transformer in the region by least square methodAnd obtaining a fault rate function of the transformer, and performing curve fitting to obtain a fault rate curve of the retrofit equipment based on Weibull distribution. Thereby obtaining a fault rate function of the transformer as

TABLE 2 values of service life backoff factors for different service modes

Maintenance mode	Service age rollback factor
		Class A inspection and repair	0.7
Class B service	0.5
		Class C overhaul	0.3
Class D service	0.1

Calculation of post-equipment overhaul failure rate based on a service life rollback method: number 14 is taken as an example: failure rate lambda before overhaul_i0(t) 0.0465, class B service, and service life reduction factor 0.5.

According to the working life rollback method, the method for calculating the fault rate after overhaul comprises the following steps:

1. according to the formula (1) and the failure rate lambda_i0And (t) calculating the corresponding time on the fault rate function before equipment maintenance by using an inversion method. T18.62.

2. Calculating the equivalent service life after equipment overhaul by using a service life rollback method: t is t_eq＝T·(1-0.5)＝9.31。

3. Calculating the fault rate after the equipment is overhauled:

and calculating the fault rate after the equipment is overhauled through the steps of 1-3.

3) And the overhaul cost E for reducing the unit failure rate after the transformer is overhauled is taken as an evaluation index. Calculating the required maintenance cost E for the ith to-be-detected transformer to reduce the unit failure rate_i. Wherein E is_iCan be calculated by equation (2):

in the formula, λ_i0(t) is the fault rate before the i-th equipment to be inspected is overhauled, lambda_i1(t) calculating the fault rate after the overhaul of the ith transformer to be inspected, F, for the service life rollback method_ijThe overhaul cost of the ith equipment to be examined in the j-class overhaul mode is shown.

4) And according to E_iAnd 5 overhauling sequences of the transformers to be detected are arranged from small to large.

And calculating the change value of the fault rate after the equipment is overhauled, and referring to the values of service life rollback factors of different overhauling modes in the table 2. And calculating the fault rate and E after the maintenance of the transformer to be detected to obtain the calculation result shown in the table 3.

TABLE 3 index calculation results after overhaul of the Equipment

From the table calculation results, according to E_iThe inspection sequence of the transformers to be inspected is that the transformers are numbered as 27, 19, 11, 14 and 15 in sequence from small to large.

Claims

1. A method for determining the maintenance sequence of a plurality of transformers is characterized by comprising the following steps: the method for determining the maintenance sequence comprises the following steps;

1) collecting the maintenance cost F of the state grade, the defect type, the maintenance mode and the j maintenance mode of n transformers to be detected in a certain area_jAnd failure rate lambda before equipment overhaul₀(t) as input parameters; the j-type maintenance mode comprises A type, B type, C type and D type;

2) obtaining service life rollback factors of different overhaul modes according to previous overhaul results of equipment, and calculating fault rate lambda (t) before and after overhaul of transformer to be inspected by using the service life rollback method₁；

Namely, a least square method is adopted to obtain a fault rate function of the transformer, curve fitting is carried out, and a fault rate curve of the retrofit equipment based on Weibull distribution is obtained:

in the formula, alpha is a scale parameter, beta is a shape parameter, C is a constant, and t is the service age of the equipment;

3) the overhaul cost E for reducing the unit failure rate after the overhaul of the transformer is taken as an evaluation index; calculating the required maintenance cost E of the ith to-be-detected transformer for reducing the unit fault rate by the formula (2)_i；

In the formula, λ_i0(t) is the fault rate before the i-th equipment to be inspected is overhauled, lambda_i1(t) calculating the fault rate after the overhaul of the ith transformer to be inspected, F, for the service life rollback method_ijThe maintenance cost of the ith equipment to be detected in the j-type maintenance mode is 1,2,. and n;