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DMC3S - Manual - 08 - 2021
1 GENERAL INFORMATION
— Preface
Protection and control panels can be installed to the risers of the MV section and HV user line of
primary substations supplied by ENEL Distribuzione S.p.A.
The devices can also be installed to MV nodes and primary substations operated with neutral to
ground or very low neutral resistance in foreign countries in which ENEL has operations.
To supplement the protection functions, the system includes the following functions: breaker failure
(BF), CT monitoring (74CT), VT monitoring (74VT), trip circuit monitoring (74TCS), Synchrocheck relay,
EAC (Equilibratore Automatico di Carico) [ALB frequency (Automatic Load Balancer)] protection,
programmable logic controller (PLC) and automatic reclosing (79).
The system can be calibrated, programmed and its logs and values read with a PC running the Thy-
Setter software, or via Ethernet; all the above operations are also available via the front panel keypad
(MMI).
2 DESCRIPTION
— Main Characteristics
• Three phase with definite 1A or 5A nominal current selectable via software.
• One residual current input with 1A or 5A nominal current selectable via software.
• Three phase with nominal voltage programmable in the range 50...130 V (U
R
=100V) and one residual
input with nominal voltage programmable in the range 50...130 V (U
ER
= 100V).
• Backlight LCD graphic display.
• Multicolour indicator LED on the front panel, freely programmable.
• Logical inputs on input board (IN1-1...IN1-6), freely programmable.
• Logical inputs on input board (INC-1...INC-5).
• Output relays (KS1-1...KS1-6) independently programmable, for protection functions, self-test and
control functions, and outputs with solid state relays.
• One rear port for communication with remote communications and control systems via Ethernet,
running the IEC 61850 protocol.
• Two rear ports for communication with remote I/O modules via Ethernet, running the MODBUS
TCP/IP® and IEC61850 protocols.
• One front panel Ethernet port, for local communications, running the MODBUS TCP/IP® protocol.
• Calendar clock with buffer.
• Nominal frequency 50 or 60 Hz, programmable via software.
The major operational characteristics are:
• Measurement of the effective value of the fundamental component of the currents and voltages
using DFT (Discrete Fourier Transform).
• The directional current function employs a special operating criterion based on a voltage memory
algorithm: this enables the relay to operate properly even in case of three-phase dead short when
the line voltage goes almost to zero.
• Logging of recent malfunctions (SFR) and events (SER).
• Logging of oscilloscope readings (DFR) in the COMTRADE format.
• All settings and logged data (faults, events, couinters, oscilloscope) are saved to non-volatile mem-
ory and are thus available even in case of auxiliary voltage failure
• Option to update the firmware.
— Protection Functions
• 27CC(80.s) Direct undervoltage
• 32P Directional active overpower
• 46 Negative sequence overcurrent
• 50/51 Phase overcurrent
• 50N/51N Residual overcurrent
• 51N(E) Neutral overcurrent
• 51N(Eme) Residual emergency overcurrent
• 51(SQL) Neutral unbalance overcurrent
• 59 Overvoltage
• 59N Residual overvoltage
• 59N(Eme) Residual emergency overvoltage
• 67 Phase directional overcurrent
• 67N Ground directional overcurrent
— Control Functions
• 25 Synchrocheck relay
• 79 Automatic reclosing
• 74CT Phase CT monitoring
• 74VT Line VT monitoring
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