ALIND AN Series, Руководство пользователя

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TECHNICAL DATA &
Page 3 of 7
ANC 303
CHARACTERISTIC CURVES
ALUMINIUM INDUSTRIES LIMITED
Relays Division
DESCRIPTION OF PROTECTION FUNCTIONS
ANC 303 (AN Series) relay is a functional relay (Current unbalance protection and IDMT Over
current protection etc) designed to be used for the protection of capacitor banks. Capacitor banks
are used in the power system for compensating the reactive power and for filtering harmonics. The
capacitor banks are usually protected against overload caused by internal faults in the bank.
Protection against unintentional reconnection of a charged capacitor to an energized network is also
to be included. All these functions are incorporated in the capacitor bank protection relay.
1. IDMT over Current Protection
The IDMT element use standard inverse of characteristics (3 sec Delay Curve). Its graphical
representation as shown in Figure.
3 sec Delay Curve
t =3k/log [PSM]
Where,
k= Time Multiplier Setting (TMS)
t = Operating time in second
TMS = Time multiplier setting
PSM=Fault Current/Plug Setting
2. Current unbalance Protection
The capacitor bank is protected by means of an unbalance current protection. The capacitor bank is
connected as a bridge and an unbalance sensing current transformer is provided. The current is
settable from 2.5 to 100% in steps of 0.50 % and operating time from 0 to 1 sec in steps of 1ms.
3. Capacitor Bank Switching IN/OUT
Microcontroller based Intelligent Automatic Power Factor Controller/Regulator/Correction Relay with
on-line monitoring of Feeder current. The Unit uses one of the tried and time tested intelligent
algorithms to switch the capacitor banks, in a most optimum combination in a shortest time for any
dynamic load conditions without the need to select the switching by user.
Capacitor banks can be connected to the system based on the load pattern. Switches on/off the
necessary capacitor banks depending upon the load current, the target power factor can be
achieved effectively.