SMART GRID CONSTRUCTION COMPONENTS

Components of the Smart Grid construction

Application: load disconnector motor drive and power feed of the recloser.

Basic requirements of the voltage transformer:

Standards of the voltage transformer to apply: IEC60044-2;

Rated voltage: 12 kV and 24 kV;

Burden output: 500 VA and 600 VA;

Factor of overvoltage: 1.2hUn continuous;

Operating temperature: -40°C and +40°C;

Type of isolation: dry compound;

Places for installation: wooden pole, outside.

Basic information

Manufacturers neglected IEC standards and international recommendations approved by series of tests to apply proper manufacturing methods. At the end of the twentieth century many companies from all countries began dynamic work in this field and this activity has showed first problems with the voltage transformers. However some companies have limits for the cost of the system implementation. Such limitations can cause failures and unsuccessful results that could lead to heavy loses for companies. For better understanding what could happen when international standards have not realized correctly by project parties there is an example of a situation given below.

General information about the case

In November 2009 started the realization of the Smart Grid project under the initiative of "EESTI ENERGIA JAOTUSVÕRK -DISTRIBUTION NETWORK”. In January 2010 the installations of the voltage transformers were stopped because of the given below failures.

 

The case description

According to the plan of the project 160 transformers were prepared for the installation. Still only 132 transformers were installed because of their defects. In basic requirements -40°C and +40°C are named as operating temperatures. On the practice -10°C was the real temperature when the voltage transformer insulation was damaged due to the one or even more fractures. Short-circuit was caused by humidity and even followed by the explosion of the voltage transformer in some cases. This explosion could cause serious problems in recloser operation or even damage the nearest devices with the hot smoke or exposed parts. As the result the recloser must be replaced with the new one because such damages can not be repaired.

Summary