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5. Installation Guideline
5.1 General
Correct installation is of prime importance.
The instructions given by the manufacturer
must be carefully studied and followed. It is
good practice to wear gloves to handle the
parts during installation.
All the safety recommendations at the beginning of the docu-
ment must be complied with during installation and commis-
sioning.
5.2 Before installing the apparatus
Please refer to all installation requirements as indicated in prod-
uct catalogue.
IMPORTANT
: Check the sense of rotation in the power plant
before installing a DS1.
Effectiveness of the diode method depends on the correct
sense of rotation setup of the MV Power Bus Bars.
DS1 is designed for a direct sense of rotation
(R, S, T or A,
B, C in time domain). Swap the S (or B) and T (or C) phases
with each other if the sense of rotation in the installation is in
reverse.
Figure 13. Identification of DS1 phases
5.3 Installation requirements
Indoor
The design of the DS1 makes the synchronous switch suitable
for indoor applications.
Harmonic distortion on voltage
The DS1 can perform synchronous operations even with high
values of total harmonic distortion on voltage (THDV).
However, this value must not be such that it will cause multiple
zero-crossing of the voltage waveform.
Rated frequency
The DS1 can perform synchronous operations even when the
power frequency is subject to variations compared to the rated
value, by automatically adjusting its actuation time.
Such variations must not, however, exceed ±1.4 Hz.
Ungrounded capacitor banks
The synchronization signal acquisition logic of the DS1 is suit-
able for operating only on capacitor banks. These capacitors
must have an ungrounded centre of the star.
In case of retrofit on an existing capacitor bank with inrush
reactors, such reactors must be eliminated or the DS1 must be
electrically located downstream with respect to them.
Capacitor discharge
When a capacitor bank is disconnected from the network, the
capacitor units remain charged to the voltage at which they are
disconnected. These must therefore be discharged to a voltage
value less than or equal to 50 V within 5 minutes, before being
connected again, according to the standard IEEE C37.99.
To prevent reclosing before the capacitors are discharged,
once the opening operation has been performed, the DS1 clos-
ing command is inhibited for 5 minutes by the control unit, thus
ensuring that it is impossible to perform closing operations on
the charged capacitor banks.
The DS1 is can perform the following operational sequence:
C – 300 ms – O – 5 min – C
Contact ABB if the inhibition time needs to be changed.
In any case, the closing of a non-discharged bank must never
be carried out with DS1.
Voltage sensor
The DS1 requires the measurement of busbar voltage on phase
R (A) by means of a voltage sensor. Only one sensor is needed,
since the load is symmetrical (floating star centre) and purely
capacitive.
DS1 has been tested and certified with the ABB KEVA 24 A3
sensor. ABB recommends the use of an ABB KEVA 24 A3 sen-
sor or equivalent.
The ABB KEVA 24 A3 sensor is not included in the DS1.
Provided
by
Northeast
Power
Systems,
Inc.
(NEPSI)
