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G E N E R A L D E S C R I P T I O N
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4.3 Pole assembly
08 Embedded single
Figure 11 provides detailed information about the
voltage sensing (3VS)
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pole assembly. The top terminal stud is connected
09 Embedded dual
to a capacitive voltage sensor enclosed within
voltage sensing (6VS)
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a protective casing. This sensor is directly linked
10 Integrated dual
to the fixed contact stud located at the upper end
voltage sensing (IDVS)
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of the vacuum interrupter. The current transfer
11 Recloser pole assembly
assembly is secured to the lower end of the vacuum
interrupter. The lateral stud terminal passes
through a ring-type current and capacitive voltage
sensor before exiting the molded assembly.
The transformer's secondary current output leads,
along with the voltage sensing leads, are also
encapsulated and brought down to a terminal block
mounted on the side of the actuator assembly.
In the case of GridShield
are taken out of their individual compartments
and connected to the junction box. The junction
box serves as an interface with the control cable.
If the control cable is disconnected from the
recloser, the OCP installed across the CT leads
in the recloser cabinet will prevent voltage
buildup on the CT secondary.
For a single voltage sensing unit (3VS), a voltage
sensor is embedded within the horizontal bushing
(see figure 8). In the case of an embedded dual
voltage sensing unit (6VS), both the Y-side
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08
3SP units, these wires
®
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09
10
(horizontal) and Z-side (vertical) voltage sensors
are embedded within the HCEP pole (refer to
figure 9). In an integrated dual voltage sensing
unit (IDVS), the horizontal bushing contains one
embedded voltage sensor, while the vertical
bushing features an integrated VLS voltage sensor
(see figure 10). The embedded current transformer
on the horizontal bushings typically has a ratio
of 600:1. However, the embedded dual voltage
sensing unit also offers the option of a 300:1 CT
ratio. The CT ratio is generally set during
manufacturing but can be adjusted in the field.
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Table 1: CT and voltage sensor ratios
CT
ratio
ratio Y-side
3VS
600:1
10,000:1
Single voltage
sensing
6VS (15/27 kV only)
600:1
10,000:1
Embedded dual
voltage sensing
300:1
3VS + integrated
600:1
10,000:1
Integrated dual
voltage sensing
using VLS sensors
Current sensing accuracy: ±3% for metering and ±10% for protection.
Voltage sensing accuracy: ±1% between -10° C and +40° C on
horizontal and vertical bushings.
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11
13
Voltage
Voltage
sensor
sensor
ratio Z-side
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10,000:1
2200:1
(15/27 kV)
5000:1
(38 kV)
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