GENERAL
13
2 G E N E R A L
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Preface
Protection developed for use as general protection for users connected to the distribution network
MT in applications where overcurrent protection functions are provided directional and non-directio-
nal phase and directional ground.
Relay can be used on radial and / or MV and LV meshed networks to protect lines and power tran-
sformers:
• On radial lines, in rings or in parallel of any length in systems with neutral grounded, isolated,
with Petersen coil and / or resistance
• For earth-fault protection for generators connected in parallel directly at the same bar
• For earth-fault protection on both MT-BT sides of transformers
In addition to the protections of maximum phase current and maximum residual current, the following
functions are present:
• Thermal image for lines and transformers
• Maximum residual voltage
• Maximum directional earth current
The following measurement circuits are present:
• Versions with CT and VT inputs
• Three phase currents with independently selectable rated current at 1A or 5 A via software
Optionally:
• A residual current input with selectable rated current at 1A or 5 A via software
Or
• A residual voltage input, with nominal voltage programmable in the range 50 ... 130 V (UER =
100V)
To integrate the protection functions, there are the functions of failure to open the circuit-breaker
(BF), CT monitoring (74CT), VT monitoring (74VT), trip circuit monitoring (74TCS), synchronism control
and programmable logic (PLC).
The methods of calibration, programming and reading of the measurements and recordings can be
implemented through Personal Computer with Software support ( ThyVisor) or via bus RS485 or Ether-
net communication; all the above operations are possible using the keyboard frontal view (MMI).
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XMR-D EQUIPMENT MANUAL
Ed. 2.9 - 02/2021
