TEST BLOCK MMLG 01 AREVA & ALSTOM

Features • Test block can be mounted adjacent to Midos modular relays and systems • Test block obviates need to disturb protective system wiring for testing • Monitoring, isolation and secondary injection testing are simplified and quickly performed Types Available • MMLG 01 Standard test block • MMLG 02 Special test block designed for use in busbar protection schemes • MMLG 03 Horizontal version of MMLG 01 • MMLG 04 Horizontal version of MMLG 02 • MMLB 01 Multi-finger test plug • MMLB 02 Single-finger test plug MMLG 01 and MMLB 01 terminals 13 and 14 must not be used for CT connections since they may present a safety hazard. Application Although designed within the Midos range these test blocks offer facilities for monitoring and secondary injection testing any power system protection scheme, when used with the multifingered test plug type MMLB 01. A single-finger test plug, type MMLB 02 is also available for monitoring the current flow in individual circuits which have been routed through the test block. Before use, the insulation of the flying leads should be visually checked for damage. The continuity of the shorting plug/ wire links, and the state of their insulation, should be checked before insertion into the MMLG 01 test block. Description, Installation and Use The Safety Statements Publication R5948 should be read before installing or using the test block ( MMLG) or test plug ( MMLB) . Note. Terminals 13 and 14 have short contact fingers which must not be used for CT connections. Refer to the Mechanical Details section for a description of the test block ( MMLG) and test plug ( MMLB) . The MMLG cover, when in place, provides protection from electric shock hazard. Care should be taken to ensure that MMLG 01 covers are correctly orientated when replaced. The test block carries 14 circuits, each of which is brought out to separate pairs of terminals at the rear of the case. Each circuit comprises a pair of internal contacts which are normally sprung together to complete the circuit link through the block when the associated protective equipment is in normal service. Access to these internal circuits for testing purposes, can be gained by removing the front cover. A metallic probe secured to the inside face of the MMLG 01 cover is automatically withdrawn when the cover is removed, so interrupting the circuit between terminals 13 and 14. By routing the main dc auxiliary supply to the protection scheme or relay through this circuit, removal of the test block cover will thereby prevent inadvertent tripping of the protection during the ensuing tests.