CPU module+base PM863K01

CPU module+base PM863K01

CPU module+base PM863K01

The WEI function sends back (echoes) the received signal under the condition that no fault has been detected on the weak-end by different fault detection elements (distance protection in forward and reverse direction). The WEI function can be extended to trip also the breaker in the weak side.

The trip is achieved when one or more phase voltages are low during an echo function. In case of single-pole tripping, the phase voltages are used as phase selectors together with the received signal CRLn.

Together with the blocking teleprotection scheme some limitations apply:

• Only the trip part of the function can be used together with the blocking scheme. It is not possible to use the echo function to send the echo signal to the remote line IED. The echo signal would block the operation of the distance protection at the remote line end and in this way prevents the correct operation of a complete protection scheme.

• A separate direct intertrip channel must be arranged from remote end when a trip or accelerated trip is given there. The intertrip receive signal is connect to input CRL.

• The WEI function shall be set to WEI=Echo&Trip. The WEI function block will then give phase selection and trip the local breaker. Avoid using WEI function at both line ends. It shall only be activated at the weak-end.