General methods for assessing the condition of electrical equipment based on the results of measurements and tests

The main method condition assessment of new electrical equipmentending with installation and put into operation, is a comparison of the results of measurements and tests with admissibility provided by special rules.

The main regulatory documents are standards for testing electrical equipment (hereinafter referred to as standards) and Rules for Electrical Installation (PUE).

The standards contain the requirements for the necessary types of inspections and tests and the standard values ​​to which their results must correspond for all types of electrical equipment of electrical installations. Norms provide for the permissible resistance of windings, contacts and other parts under voltage, the permissible state of insulation; test voltages, etc.

According to PUE and Norms, the conclusion about the possibility of putting the equipment into operation is made on the basis of the totality of the results of the acceptance tests, since it is often difficult, especially in matters of assessing the state of the insulation of electrical machines, power transformers and the need for drying , to find a solution according to one or even two criteria.

Widely used in production of commissioning and installation works in equipment condition assessment, a method of comparing the measurement results of a group of the same type of equipment based on the assumption that all tested equipment of the same type cannot have the same failures.

So, for example, if the magnetization characteristics of a group of measuring current transformers are uniformly lower than typical, and the open circuit current of several measuring voltage transformers equally exceeds the permissible value, this means that there is no damage to the insulation of the windings or the magnetic circuit, but using the worst steel in the magnetic circuit during the production of the transformer cores in the factory or changing the dimensions of the steel.

Often the results of tests and measurements (characteristics of AC and DC generators, insulation measurements, etc.) are compared for evaluation with the results of previous measurements and tests. for newly commissioned equipment, these are the results of factory measurements and tests.

The checks and tests provided for in the standards are not always sufficient. This applies to non-production equipment or prototypes.In such cases, the work is carried out in accordance with a special program drawn up by the developer or by the design organizations or the manufacturer, the representatives of the commissioning organizations must participate in the preparation of programs.

The last way to evaluate the ability to turn on electrical equipment or connect to work is to fully test it in service.