S&C BankGuard PLUS, Installation Manual

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S&C Instruction Sheet 1011-510
11
Grounded Wye Banks
Installation
Installation consists of several operations. The details of these operations, and the order
in which they must be carried out, depend on the type of control device, and on local
or customer codes, standards, and procedures. The following information is specifi c to
BankGuard Plus Controls protecting
grounded wye-connected capacitor banks .
The required fuse blocks and fuses are furnished with the control, and you must
installthem. When you design the installation, be sure to provide adequate ventilation;
the temperature near the control should not exceed 160°F. This is particularly important
when the control is installed in a cabinet or when several controls are installed close
together.
To ensure that the control is not subjected to excess surges (ANSI Standard C37.90a),
we recommend the following:
• Provide adequate shielding for the control-circuit wiring. Refer to the interconnection
diagram furnished.
• For installations involving two or more grounded-wye capacitor banks in the same
station, interconnect and ground their neutrals at a single point only. Also, to reduce
inrush current and transient voltage disturbances, you may want to equip the capacitor
bank switching devices with pre-insertion resistors or to provide current- limiting
reactors.
For a grounded wye-connected capacitor bank, the BankGuard Plus control requires
three potential devices to monitor intermediate tap point voltages. The intermediate tap
point for each phase of the bank should be located as follows:
• For capacitor banks with an even number of series groups per phase , the number
of series groups between the tap point and ground should equal the number of series
groups between the tap point and the line.
• For capacitor banks with an odd number of series groups per phase , the number of
series groups between the tap point and ground should be one less than the number
of series groups between the tap point and the line.
Step 1
Read and make sure you understand the following warnings before you begin
installatin or operate this equipment.
Ç
WARNING
These instructions do NOT replace the need for utility operation standards. Any
conflict between the information in this document and utility practices should be
reviewed by appropriate utility personnel and a decision made as to the correct
procedures to follow.
Serious risk of personal injury or death may result from contact with electric
distribution equipment when electrical isolation and grounding procedures are not
followed. The equipment described in this document must be operated and main-
tained by qualified persons who are thoroughly trained and understand any hazards
that may be involved. This document is written only for such qualified persons and
is not a substitute for adequate training and experience in safety procedures for
accessing high voltage equipment.
This control is connected to capacitors operating at primary voltage levels. High
voltage may be present in the wiring to the control or the control itself during cer-
tain failures of the capacitor bank wiring or system grounding, or due to a failure
of the capacitor bank itself. For this reason, access to the control should be treated
with the same safety precautions that would be applied when accessing other high
voltage lines and equipment. Follow all locally approved safety procedures when
working on or around this control.
Do not energize the control power source entering the control enclosure until all
wiring is complete.