ABB SPAU 341 C Voltage regulator SPAU341C How to set it up?

ABB  SPAU 341 C Voltage regulator SPAU341C How to set it up?

The voltage regulator SPAU 341 C is intended

to be used for regulating the voltage of power

transformers with on-load tap-changers in distribution

substations. The connections required

for a simple voltage regulating function is the

measured phase-to-phase voltage U12 and the

raise and lower output contacts. If the line drop

compensation, the minimizing circulating current

or the overcurrent blocking feature is to be

used, one or more phase currents have to be

measured. If only one phase current is measured,

it is always connected to the terminals of

the phase current I L1, and the current to be

measured is selected with the software switches

SGF2/6 and SGF2/7 of the automatic voltage

regulating module SPCU 1D50.

The purpose of the regulator is to maintain a

stable secondary voltage of the power transformer.

The basis for this operation is the reference

voltage, which is set by the user. By adding

or decreasing various compensation factors, the

regulator calculates a control voltage from the

reference voltage. Hence, the control voltage is

the desired transformer secondary voltage to be

maintained by the regulator. Then the control

voltage is compared with the voltage measured

and the difference between these two forms the

regulating process error.

Since the tap-changer changes the voltage in

steps, a certain error has to be allowed. This error,

called bandwidth, is also set by the user. If

the measured voltage fluctuates within the bandwidth,

the regulator is inactive. Should, on the

other hand, the measured voltage be outside

these bandwidth limits, an adjustable delay T1

starts. This delay T1 remains active as long as

the measured voltage is outside the hysteresis

limits of the bandwidth. The factory setting of

the hysteresis limits is 90%.

Should the measured voltage still be outside the

hysteresis, when the delay counter T1 reaches

its setting value, the raise or lower output relay

is activated and the motor drive of the tapchanger

is operated. If, on the other hand, the

measured voltage falls within the hysteresis limits,

the delay counter is reset.

Should one tap-changer operation not be

enough to regulate the transformer voltage

within the hysteresis limits, a second adjustable

delay T2, usually with a shorter time setting than

T1, starts.

The delays T1 and T2 can be selected either

with definite or inverse time characteristic. Inverse

time characteristic means, that the delay

is inversely proportional to the regulator error,

i.e the delay is inversely proportional to the difference

between the control voltage and the

measured voltage.

The voltage regulating function will be described

more in detail in the document 1MRS 750111-

MUM EN.

Block Blocking of regulating function, input

Uaux Auxiliary voltage, input

RSV Reduce set voltage or parallel input

AUT/MAN Automatic or manual mode, output

IRF Self-supervision signal, output

RAISE Raise signal, output

LOWER Lower signal, output

I> Overcurrent or overvoltage blocking, output

U< Undervoltage blocking output

SERIAL PORT Serial communication port

TAP POS Tap-changer position input, mA signal

TCO Tap-changer operating input

RAISE' Raise command or parallel operation input

LOWER' Lower command or reduce set voltage input

AUTO' Automatic mode input

MAN' Manual mode input

U1 Automatic voltage regulating module SPCU 1D50

U2 Manual voltage regulating module SPCN 1D56

U5 I/O module

U6 Energizing input module

SPA-ZC_ Bus connection module

Rx/Tx Fibre-optic receiver (Rx) and transmitter (Tx) of the bus connection module

The power supply module is located behind the

system front panel of the regulator and can be

withdrawn after removal of the system front

panel. The power supply module produces the

voltages required by the regulating modules

from the auxiliary voltage.

There are two types of power supply modules,

differing only in input voltage:

SPGU 240 A1:

Rated voltage Un = 110/120/230/240 V ac

Un = 110/125/220 V dc

Operative range U = 80…265 V ac/dc

SPGU 48 B2:

Rated voltage Un = 24/48/60 V dc

Operative range U = 18…80 V dc

Which power supply the regulator contains, is

marked on the system panel.

The power supply module is a transformer-connected,

i. e. galvanically separated primary and

secondary circuits, flyback type rectifier. The

primary circuit is protected by a 1 A fuse, F1

(slow), in SPGU 240 A1, and a 4 A fuse (fast)

in SPGU 48 B2. The fuses are located on the

circuit board of the module.

When the power supply module is operating,

the green LED indicator Uaux on the system

panel is lit. The supervision of the supply

voltages for the electronics is incorporated into

the regulating modules. A self-supervision alarm

is given if one of the secondary voltages differs

by more than 25% from the rated value. An

alarm signal is also obtained, if the power supply

module is missing, or if the auxiliary voltage

to the regulator has been interrupted.