31
Instruction Booklet
IB156002EN
Effective January 2022
Eaton HCU2/HCUn active harmonic
filter installation manual
EATON
www.eaton.com
General CT information
The CT must be orientated properly during installation. The orientation
is specified in the drawings with an arrow indicating the direction or
polarity of the CT. Most CT manufacturers will indicate orientation
with a label indicating H1 on one side of the CT or a dot. There can
also be a label indicating H2 and/or an arrow on the CT. The H1 side of
the CT should always be closest to the power source. If the CT has
an orientation arrow, it should point from the source towards the load.
See the installation instructions for the specific CTs being installed.
A shorting terminal block or shorting switch with galvanic isolation
to the active filter for the CT secondary is recommended. Insert an
interposing terminal block in a separate enclosure with the ability to
short the secondary wiring of the CT. CT shorting blocks provide the
ability to short the CTs without entering the active filter enclosure
(which otherwise would require a power shutdown). CT shorting
terminal blocks are available in the catalog. A four-pole shorting block,
Eaton part number TXSB is available as a separate sale item.
CT location is defined in relationship to the active filter system. CT
location on the “Source Side” indicates that the CTs are physically
located upstream of the active filter. The CTs will measure the
improvement to the current as a result of the active filter operating.
A CT location on the “Load Side” indicates that the CTs are
downstream of the active filter. The CTs will monitor the load current
provided by both the source and active filter currents.
For applications where the harmonic correction unit is being used in
conjunction with power factor correction capacitors, please contact
Eaton’s Technical Resource Center for additional current transformer
configuration requirements.
NOTICE
MEASUREMENT ERRORS.
CTS MUST BE PHYSICALLY SEPARATED FROM ANY PERPENDICULAR
CONDUCTOR BY AT LEAST 25 MM (1 INCH) FOR EVERY 1000 A OF
CURRENT FLOWING THROUGH THE PERPENDICULAR CONDUCTOR.
FAILURE TO FOLLOW THIS INSTRUCTION CAN RESULT IN A REDUCTION
IN PERFORMANCE OF THE ACTIVE FILTER.
IF THIS PRACTICE IS NOT FOLLOWED, THE MAGNETIC FIELD PRODUCED
BY THE CURRENT FLOWING ON THE PERPENDICULAR CONDUCTOR
WILL CAUSE CT MEASUREMENT ERRORS.
Minimum CT requirements
The active filter uses a minimum of two external current
transformers (CTs) to measure load current waveforms. The CTs
should be mounted on phases L1 and L2 with H1 facing the source.
Systems that are using two CTs can have the CTs installed on L1
and L3 or L2 and L3 if necessary. If L1 and L3 or L2 and L3 CT
configurations are used, this information must be provided to the
qualified person commissioning the unit. Three external CTs are
required if line-to-neutral connected loads are present.
NOTICE
REDUCED PERFORMANCE.
CT WIRING MUST BE ROUTED SEPARATELY FROM POWER CABLES.
FAILURE TO FOLLOW THIS INSTRUCTION CAN RESULT IN A REDUCTION
IN PERFORMANCE.
CT wiring must be routed directly from the conduit entry-plate to
the terminal block of the CT board.
CT must be selected for:
•
5 A secondary
•
100 to 10,000 primary rating
•
50/60 Hz or 400 Hz rated
•
Type 1 accuracy
•
The CT shall be metering class, primary rating as required,
5 A secondary rating. The minimum Burden designation is B-0.5,
as defined in IEEE
®
Standard C57.13-2008
•
The CT primary current rating must exceed the maximum load
current where they are installed
•
The maximum burden (in VA) on the CT is formed by the CT
wiring and total active filter burden. This is equal to 1.0 VA for
CTs with a 5 A secondary rating or 0.04 VA for CTs with a 1 A
secondary rating
•
Wire size of the CT should be 4 mm
2
(12 AWG) or 6 mm
2
(10 AWG). Consult the CT manufacturer for secondary wiring
recommendations. See
Table 10
–
Table 13
on
page 32
for
adding wire to CT secondary wiring
CT secondary wiring must be either twisted and/or shielded pairs
Do not connect the active filter CT to any other loads. Use a
separate current transformer if additional uses are required.
Any splicing to the CT leads needs to be done with CT shorting
blocks. A four-pole shorting block, Eaton part number TXSB, is
available as a separate sale item.
Tap 2 of each CT installed must be grounded as close to the CT as
possible. Tap 2 is the higher of the two CT secondary terminals being
used. For multi-ratio CTs, Tap 2 may be a terminal other than X2. For
example, if CT secondary terminals X1 and X5 are used to obtain the
desired CT ratio, X5 is Tap 2.
A single active filter, not operating in parallel, can have the CTs
installed either on the source side or load side of the active filter.
Parallel systems must have the main CTs installed on the source
side of the active filter system.
CT to CT board connection
The CT connection is made behind the small customer access panel
at the bottom of the active filter chassis. See
Figure 21
on
page 24
.
Remove the customer access panel. The CT board is located behind
and slightly below the control board. This is the location where the
active filter CT secondary wiring must be terminated. Remove the
clear plastic safety cover to access the CT board.
Typically, L1 CT will be connected to CH1 IN. There are two X1
and X2 IN terminals. The second set of IN terminals can be used
to connect additional CTs that may be required for site specific
conditions. X1 and X2 OUT are used for parallel active filter systems.
The terminal block on the CT board for the HCU2 can accept wire
sizes of up to 6 mm
2
(10 AWG) wire and has a torque specification
of 1 N·m (9 Ib-in).
The terminal block on the CT board for the HCUn can accept wire
sizes of up to 2.5 mm
2
(14 AWG) wire and has a torque specification
of 0.6 N·m (5.3 Ib-in).
NOTICE
CIRCULATING CURRENTS.
WHEN USING SHIELDED CT SECONDARY WIRE, ONLY GROUND THE
SHIELD AT ONE END OF THE CABLE.
FAILURE TO FOLLOW THIS INSTRUCTION CAN RESULT IN A REDUCTION
IN PERFORMANCE.
NOTICE
INACCURATE FILTER OPERATION.
DO NOT ALLOW THE CONDUCTOR ON WHICH THE CT IS MOUNTED TO
BECOME LODGED IN THE JOINT AREA OF A SPLIT-CORE CT.
FAILURE TO FOLLOW THIS INSTRUCTION CAN RESULT IN INACCURATE
FILTER OPERATION.
