Overview and Significance of Condition-based Maintenance of Power Equipment

Condition-based Maintenance (CBM) refers to the equipment status information provided by advanced condition monitoring and diagnostic technology to judge the abnormality of the equipment, predict the failure of the equipment, and reasonably arrange the maintenance items and periodic maintenance methods according to the predicted failure information , that is, to arrange the maintenance plan according to the health status of the equipment and implement the equipment maintenance.

The condition-based maintenance of power equipment is to ensure the scientific maintenance of power equipment, ensure the safety and economic reliability of the power equipment operation process, and realize the continuous improvement of the economic benefits of power enterprises.

1. Purpose of Condition Based Maintenance

Condition-based maintenance is a maintenance strategy for enterprises to achieve safe and reliable operation and reasonable maintenance costs through equipment condition evaluation, risk assessment, and maintenance decision-making based on safety, reliability, environment, and cost.

2. The role of Condition Based Maintenance

In general, the electrical equipment of the power system is overhauled (or maintained, debugged, tested) according to the prescribed overhaul period, and the period is fixed for one year or several years.

With status detection, relevant experts can easily browse the current and historical status of any equipment in the managed substation in the office, and can quickly predict the future status of the equipment. For equipment with potential failures, relevant experts from the whole city, province, and even manufacturers can be organized to conduct remote diagnosis on the Internet to decide whether to overhaul, when to overhaul, and which parts to overhaul.

3. Contents of Condition Based Maintenance

Status detection mainly includes three aspects.

3.1 Substation field components. Various sensors (including pressure, temperature, humidity, voltage, current, displacement, etc.), collectors, concentrators, on-site background software and main screen, etc.

3.2 Communication channel (can be shared with dispatch automation). For example, optical fiber, carrier wave, and wireless spread spectrum. If the network coverage permits, the current popular ADSL line and VPN router can also be used to realize a virtual private network between the substation and the dispatching center through encryption.

3.3 Provincial and municipal expert analysis system platform. By collecting the actual management methods of each relevant unit, compiling a popular management program, realizing the sharing of resources and status among the relevant units, and realizing remote diagnosis.

There are two deficiencies in regular maintenance: one is that when there are potential unsafe factors in the equipment, the hidden dangers cannot be eliminated in time because the time for maintenance has not arrived; Large blindness causes waste of manpower and material resources, and the maintenance effect is not good.

Condition-based maintenance is based on the operating status of equipment, and it is a purposeful work. Therefore, the premise of condition-based maintenance is to do a good job of condition detection. Status inspection has two main functions: one is to detect equipment defects in time to prevent problems before they happen; the other is to provide convenience for the operation and management of main equipment, provide a basis for maintenance, and reduce the waste of manpower and material resources. It can be seen that condition detection is a necessary means of condition maintenance.

The concept of condition-based maintenance is to have reliable guarantee measures (other monitoring methods: such as online monitoring of equipment heating, operating parameters, testing insulating oil and gas analysis data during operation) and basis (previous maintenance , debugging, and test conditions are good), appropriately extend or shorten (if the data is bad, it may also shorten) the maintenance cycle, and perform maintenance according to the operating conditions and insulation status of the equipment.

There are also some manufacturers whose products are operated according to the service life of the equipment after leaving the factory, and the regulations do not allow maintenance. This is generally limited to a small number of foreign imported equipment and some joint venture products.

4. Significance and status quo of Condition Based Maintenance

Condition-based maintenance can reduce unnecessary maintenance work, save man-hours and costs, and make maintenance work more scientific. However, there is also great resistance to the implementation of condition-based maintenance work at present: some management departments emphasize the implementation of regulations in routine inspection work, and electrical equipment has not been overhauled according to the maintenance period to be assessed (points deducted in the evaluation); In line with the attitude of being cautious and prudent, the operator followed the rules and regulations step by step, so that the condition-based maintenance could not be implemented well.

5. Condition Based Maintenance specification

5.1 Introduction to condition-based maintenance

Condition-based maintenance is a complex and systematic project, and it is necessary to establish a complete set of management system, method mechanism, technical means, guarantee system and other specifications to realize the condition-based maintenance of equipment.

5.2 Management system

The management system mainly focuses on the organizational form required by the condition-based maintenance work and the related responsibilities and division of labor of the organizational form, and the main work process system of the condition-based maintenance, including the organizational system, work process, performance evaluation, etc. Overhaul the process system of the three-level evaluation system.

5.3 Method mechanism

The method mechanism refers to the mechanism and method used in the condition-based maintenance work, such as the detection method, definition of state quantity, evaluation method, evaluation model, etc. that need to be used for state evaluation of various electrical equipment. It is mainly reflected in a series of test procedures, evaluation guidelines, technical guidelines, maintenance process guidelines, etc.

The research content of the method and mechanism includes: for different types of electric equipment, research on the failure modes of these equipment, research on the applicability of the condition-based maintenance management mode, the definition of equipment characteristic quantities and state quantities, the research on the acquisition method and storage method of state quantities, and the condition-based maintenance. Evaluation, research on diagnostic methods, research on condition-based maintenance evaluation management processes, etc.

5.4 Technical means

Technical means refers to the implementation of relevant detection methods and evaluation processes through relevant technical means in the state evaluation work. At present, the most widely used method is the equipment state evaluation method based on the state quantity score weighting proposed by the State Grid Corporation of China. Of course, there are other evaluation methods that may be better. Each method has its own advantages and limitations. In order to better realize professional and standardized condition-based maintenance management, refer to the existing safety evaluation methods of various industries. The technical means of combining various state evaluation methods are adopted to realize the state evaluation.

5.5 Guarantee System

The guarantee system refers to the auxiliary work required to ensure the smooth implementation of condition-based maintenance, such as device network detection, operation and maintenance; standard document formulation; condition-based maintenance work simulation, personnel training, etc.

According to the above ideas, with the management mechanism, method system, technical means and guarantee system as the basic framework, the evaluation model and analysis model of the expert system software of the power equipment condition maintenance system are formed as the overall technical route of software development.

6. Maintenance overview of condition-based maintenance of electrical equipment

Power equipment must be used in the process of power transportation, so the operation status of the equipment and the quality of power supply have a vital relationship. In view of the importance of the status of electrical equipment, it is imperative to carry out maintenance and implement the maintenance work. ?

7. Significance of condition-based maintenance of power equipment

7.1 The quality of power supply can be further improved

During the maintenance process of power equipment, some hidden problems in the operation of the equipment can be discovered in time, and minor problems can be killed in the cradle, so that the equipment can not be used normally due to failure problems, and it can also lay the foundation for the improvement of the quality of power supply. good foundation. Therefore, carrying out condition-based maintenance of power equipment has a positive effect.

7.2 Condition-based maintenance of power equipment has a positive effect

The development of condition-based maintenance of electrical equipment can reduce the workload of the overall maintenance staff and share part of their responsibilities, so that the overall maintenance personnel can devote more energy to carry out other aspects of maintenance work, and the special equipment condition-based maintenance, It can also promote the operation of equipment to maintain a stable state at all times, thereby ensuring the stability of power supply.

8. Maintenance content of condition-based maintenance of electric equipment

8.1 Maintenance of the initial operating state of electrical equipment?

In the initial maintenance, you should start from the following two aspects. On the one hand, it is to determine whether the state shown in the operation of the equipment is good. If the initial operation state is not satisfactory, then it should not be put into formal maintenance. In use, secondly, during the initial maintenance, you should also have a deep understanding of the structure of the equipment and other relevant information, and master its experimental data and nameplate data and other related data information, and do a good job in the maintenance of these two aspects of equipment to ensure The effect of equipment usage.

8.2 Check and repair the status of electric equipment during operation

During the actual operation of power equipment, the state presented by the equipment is the basis of equipment maintenance work. The maintenance personnel need to analyze and understand this state in depth, and use advanced technology to conduct experiments on it, so as to fully grasp the operating state of the equipment.