ABB VD4 Series Instruction Manual - page 13
3.1 Structure of the breaker poles
(Figures 3/1, 3/2 , 3/6, 3/7 and 3/8)
The 36 kV and 40.5 kV circuit-breakers of type VD4 are
designed as withdrawable units. The poles, which are
constructed in column form, are mounted on a torsionally
rigid enclosure substructure with rollers. The live parts of the
breaker poles are located in the insulating material pole
tubes and protected from impacts and other external
influences.
With the breaker closed, the current path leads from the
upper contact arm 57.1 and a chamber holder fixed in the
pole tube to the fixed contact 58.2 in the vacuum interrupter
58, then via the moving contact 58.3 and roller contact
to the lower contact arm 57.2. The switching motion is
effected by means of the insulated coupling rod with internal
contact force springs.
3.2 Structure of the breaker operating mechanism
(Figures 3/3, 3/4, 3/7, 6/1 to 6/5, 7/5 to 7/8)
The operating mechanism located in the housing substructure
is of the stored-energy spring type and acts on the three
breaker poles. The necessary operating energy is stored
ready for activation by charging the spring energy storage
mechanism.
The stored-energy spring mechanism essentially consists
of drum 55.33 containing the spiral spring, the charging
system, the latching and operating mechanism and the
linkages which transmit the force to the breaker poles. In
addition, there are supplementary components such as the
charging motor, releases, auxiliary switches and the controls
and instruments.
The operating mechanism is fundamentally suitable for
autoreclosing and, due to the short charging times, also for
multi-shot autoreclosing.
The operating mechanism is normally fitted with a charging
motor. There is also a facility for charging the stored energy
spring manually.
There is one rating plate 55.7 with the main data of the switch
equipment on front cover plate left hand side 50.7, and
another on breaker mechanism housing.
The basic version of the stored-energy spring mechnism
is fitted with the following auxiliary equipment:
■
Shunt release OFF Y2
■
Shunt release ON Y3
■
Blocking magnet Y1 with auxiliary switch S2
■
Five-pole auxiliary switches S3 and S4
■
ON-OFF operating shaft 54
■
Mechanical switch position indicator 55.4
■
Charging condition indicator 55.8 for the stored energy
spring
■
Mechanical operating cycle counter 55.5.
■
Motor charging mechanism
■
Five-pole auxiliary switch S1 to switch the charging motor
■
Anti-pumping relay K0.
The following additional equipment can be installed:
■
Blocking magnet Y0 on the withdrawable part
■
Second shunt release OFF Y9
■
Indirect overcurrent release Y7
■
Auxiliary switch S7 for electrical opening signalling
■
Undervoltage release Y4
■
Five-pole auxiliary switch S5
3.2.1 Releases, blocking magnet and auxiliary switches
(Figures 2/4 to 2/6, 3/3, 6/2, 7/7 and 7/8)
The releases and the blocking magnet are mounted at the
bottom of the stored-energy spring mechanism.
The allocation of the auxiliary switches can be seen in the
wiring diagram of figure 2/4.
The five-pole auxiliary switch S1 is operated by the charging
condition indicator 55.8. It controls the charging motor M1,
serves as an electrical interlock for shunt release ON Y3 when
the spring energy storage mechanism is not sufficiently
charged, and also provides an electrical switching readiness
signal.
Operation of the five-pole auxiliary switches S3, S4 and S5
is dependent on the switching position of the circuit-breaker.
Auxiliary switch S3 interrupts the circuit of the optional
additional shunt release OFF Y9 with the circuit-breaker
in the open position, and the circuits of shunt release ON Y3
and the optional blocking magnet Y1 with the circuit-breaker
in the closed position. There is one further NOC for other
purposes.
Auxiliary switch S4 interrupts the circuit of shunt release
OFF Y2 with the circuit-breaker in the open position. One
further NOC and three NCCs are available for annunciation,
control and interlock purposes.
Auxiliary switch S5 can be optionally designed with any
possible combination of contacts from five NOCs to five NCCs.
Its contacts are available for any required control, annunciation
or interlock functions. The auxiliary switch is normally configured
as shown in figure 7/3.
The single pole auxiliary switch S7 (fleeting contact time 30
ms) serves to provide a fault signal ("breaker released").
With remote control, the auxiliary switch is necessarily operated
via:
■
Shunt release OFF Y2 or
VD4 Vacuum Circuit-breaker | Structure and function 13
3 Structure and function