Switching in Electrical Transmission and Distribution Systems

14 Testing

14.1 Introduction

Testing of switching equipment is usually performed with one of the following objectives:

• Research and development. These tests are normally carried out in test-laboratories of manufacturers or, when the necessary power and/or voltage is not available, in third-party laboratories. Apart from custom-designed special equipment, the aim is the development of products that will be ultimately submitted to type-tests. Research and development test requirements can vary depending on the stage of development, but the final aim is usually a design capable of withstanding the standardized stresses of a type-test.
• Acceptance. In these tests, verification is requested of withstanding non-standardized stresses that may occur under special conditions of the electrical network, environment, operation, and so on. Regarding switching, examples are TRVs beyond the standardized limits (for example in the application of series current-limiting reactors or filter banks in converter stations) or other special conditions (for example exceptional short-line fault conditions, missing current zeros, high DC time constants, etc.). Usually, equipment has already been type-tested before being subjected to the additional acceptance tests. The user of switchgear proposes the test-requirement based upon his knowledge of abnormal conditions in his system. Manufacturers and independent laboratories perform such tests.
• Type-test certification. Type tests are aimed to demonstrate ...