Completely self protected (CSP) transformer

The breaker operating mechanism is designed to be operated by a lineman's hot stick. Transformers are shipped with the circuit breakers closed.

CSP transformers are protected against secondary overloads and short circuits by an internally mounted circuit breaker. The function of the breaker is to open the low voltage circuit and protect the transformer from faults or severe overloads.

3. Secondary Breakers

CSP transformers are lightning protected by gapped or direct connected lightning arresters
bolted to mounting pads welded to the tank wall. Gapped arresters have an adjustable
electrode on the top terminal of the arrester to obtain the proper gap setting to the bushing
electrode.

2. Lightning Arresters

On CSP transformer a fusible protective link, mounted inside the tank, is provided in series with each HV terminal. In case of internal failure of the transformer, the protective link disconnects the transformer from the line without affecting line fuses or breakers. When the available fault current exceeds the maximum interrupting rating of the protective link, a current limiting fuse should be used in series with the protective link.

1. Fuses