The purpose of the TTE7015 and TTE7017 relays is to detect, as soon as it appears, any insulation fault affecting the rotor circuit of a synchronous machine.

They operate on the principle of the injection of a direct current for the TTE7015 and a very low frequency current at low levels of voltage and current for the TTE7017.

As a general rule, the field circuits of synchronous machines are insulated from earth, and thus the appearance of the first earth fault has practically no effect on the machine operation. This first fault should however be eliminated without delay, because if it is allowed to remain, a second fault of the same type would immediately put the machine out of service and could cause very serious damage to the rotor.

The purpose of the TTE7015 and TTE7017 is to detect immediately any fault on the rotor winding of a synchronous machine, in order to give an alarm and, if required, to separate the machine from the network.

They operate on the current injection principle, d.c. for the TTE7015 and low frequency a.c., with low levels of voltage and current (maximum 20 V or 5 mA r.m.s.) for the TTE7017.

Major Advantages

• Static measuring elements.
• lnsensitive to seismic shock: tests at 5 g according to IEEE standard 344.
• Auxiliary output relay with 2 high-power contacts and a handreset mechanical operation indicator.
• Very robust, small volume modular case. Nameplate with international symbols.
• Protected against severe environments : heat and humidity, saline atmosphere, corrosion and mould, termites.
• May be stored at very low temperatures (tests carried out by the L.C.I.E. at -57°C).