When different types of consumers are charged at different uniform per unit rates, it is said to be Flat Rate Tariff. In this type, the consumers are grouped into different classes. Each class is charged at different uniform rate.
Buchholz relay is gas operated relay. It will operate when internal fault occurs in transformer. It is placed between tank to main conservator. It has two contacts trip and alarm. Use of Buchholz relay in distribution transformer is not economical.
EXAMIANS