SecoGear Medium-voltage Switchgear Application and Technical Guide
DET-882
Control Power Equipment
18
©2017 General Electric All Rights Reserved
SECTION 3.
CONTROL POWER EQUIPMENT
This section of the Application Guide provides guidance on
control power requirements for SecoGear and equipment
selection.
CONTROL POWER REQUIREMENTS
Control power for SecoGear needs to have enough
capacity to provide the maximum power required at any
operating condition. It is important to have adequate
power for tripping of breakers during relay operation to
protect the breakers and switchgear. Additionally, it should
be capable of closing the breakers without direct manual
operation.
Other load requirements for DC control power equipment
include indicating lamps, relay power supplies, emergency
lights, emergency motors, and excitation power (brushless
motors, etc.); for AC control power equipment include
indicating lamps, relay power supplies, excitation power
(brushless motors, etc.), and equipment heaters.
The primary sources of control power for metal-clad
switchgear are DC control from batteries with a charger,
and AC control from a transformer. If using AC control
power, the tripping power will be obtained through rectified
AC, feeding capacitors contained within trip devices. There
are several factors in determining the best alternative
needed for each application, these can include system size,
installation conditions, reliability, footprint, operation of
breakers, maintenance, etc., and the end cost.
Breaker Close and Trip Considerations
For optimum operation of SecoGear Metal-clad switchgear,
the selected source should provide a dependable power
source sized to accommodate the required loads. The
system should provide reliable operation of all of the
electrically operated devices at their required operating
voltage ranges. The required operating voltage range of
the control power equipment is determined by the circuit
breaker. These ranges are established by ANSI C37.06
standard. Refer to Table 3-1 for specific voltage ranges
given each possible control source for SecoVac VB2+
circuit breakers.
Note that that spring charging time for SecoVac VB2+
mechanisms is approximately 3 s to 7 s.
Table 3-1: SecoVac VB2+ IEEE Circuit Breaker Control Voltages and Currents
Breaker Control
Source Voltage
Closing Voltage
Range
Tripping Voltage
Range
Closing Coil
Current
Tripping Coil
Current
Charge Motor
Inrush Current
Charge Motor
Run Current
1
48 Vdc
38 Vdc – 56 Vdc
28 Vdc – 56 Vdc
15.84 A
15.84 A
20 A
3.2 A
125 Vdc
100 Vdc – 140 Vdc
70 Vdc – 140 Vdc
2.78 A
2.78 A
8.8 A
1.2 A
250 Vdc
200 Vdc – 280 Vdc
140 Vdc – 280 Vdc
0.75 A
0.75 A
5.1 A
0.6 A
120 Vac
104 Vac – 127 Vac 108 Vac – 132 Vac
2
2.78 A
2.78 A
8.8 A
1.2 A
240 Vac
208 Vac – 245 Vac 216 Vac – 264 Vac
3
0.75 A
0.75 A
5.1 A
0.6 A
Notes:
1.
Spring charge motor run time is <15 s.
2.
120 Vac control voltage for tripping requires the use of a 120 Vac capacitor trip device. Cap. trip device delivers 170 Vdc (peak) into a DC trip coil.
3.
240 Vac control voltage for tripping requires the use of a 240 Vac capacitor trip device. Cap. trip device delivers 340 Vdc (peak) into a DC trip coil.
Table 3-2: Contact Ratings for MOC, TOC, and Breaker
Auxiliary Switches
Control Voltage Current Rating of Contacts
1
110 Vac/120 Vac 15 A
220 Vac/240 Vac 10 A
24 Vdc
15 A (max. 1 contact)
125 Vdc
10 A (max. 3 contacts in series)
240 Vdc
5 A (max. 6 contacts in series)
Control Voltage High-fidelity Current Rating
125 Vac
0.1 A
8 Vdc – 30 Vdc 0.1 A
Notes:
1.
Minimum operating current is 10 mA at 5 Vdc.
Breaker Tripping
SecoVac VB2+ circuit breakers have independent means
for tripping, either manual tripping through a push button
or electrically actuated through a trip coil. Electrically
actuated tripping devices, can be used to open the breaker
in normal switching conditions, initiated by an operator, or
to automatically open the breaker as a protective response
to abnormal conditions. Electrical tripping is accomplished
when external power, from a battery or rectified AC source
with capacitor, is directed into the breaker trip coil
Automatic tripping occurs when a protective relay senses
an abnormal system condition through the power circuit
instrument transformer, and closes output contacts in the
trip circuit.
The following points must be considered when deciding
between DC battery trip and AC capacitor trip:
The following points must be considered when deciding
between DC battery trip and AC capacitor trip
•
AC control may have lower cost than a battery system,
but it will be necessary to install a separate trip device
for each breaker and lockout relay