7SR18 Description Of Operation
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Section 1: Introduction
This manual is applicable to the following relays: -
7SR18 Line Differential Relay
The ‘Ordering Option’ Tables summarise the features available in each model.
General Safety Precautions
It is the responsibility of the user to ensure that the equipment is installed, operated and used for its intended
function in the manner specified by the manufacturer. If this is not the case, then any safety protection provided
by the equipment may be impaired.
The equipment shall be isolated or disconnected from hazardous live voltage before accesses to potentially
hazardous live parts is affected.
1.1 CURRENT TRANSFORMER CIRCUITS
The secondary circuit of a live CT must not be open circuited. Non-observance of this precaution can result in
injury to personnel or damage to equipment.
1.2 EXTERNAL RESISTORS
Where external resistors are fitted to the circuit, these may present a danger of electric shock or burns, if touched.
1.3 FIBRE OPTIC COMMUNICATION
Where fibre optic communication ports are fitted, the lasers are Class 1 devices but recommend they should not
be viewed directly. Optical power meters should be used to determine the operation or signal level of the device.
1.4 FRONT COVER
The front cover provides additional securing of the relay element within the case. The relay cover
should be in place during normal operating conditions.
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