11
The control module SPTO 6D3, the overcur-
rent module SPCJ 3C3 and the neutral current
module SPCS 3C4 measure analog signals.
The overcurrent module SPCJ 3C3 measures
the three phase currents. The measured currents
are indicated locally on the display of the over-
current module and, if necessary, transmitted to
higher-level systems over the SPA bus.
The directional neutral current module SPCS
3C4 measures three analog signals: neutral cur-
rent I
0
, residual voltage U
0,
and I
ϕ
, which is the
resistive or capacitive component of the neutral
current. The three analog signals are presented
locally on the display of the module and, if
necessary, transmitted to higher-level systems
over the SPA bus.
The relay modules also record the analog signals
in a fault situation. The relay modules always
indicate the measured values as multiples of the
rated current and rated voltage of the feeder
terminal.
The standard control module is provided with a
pulse counter input for the counting of the
energy pulses. To be able to measure analog
signals the control module SPTO 6D3 requires
an optional measuring module: type SPTM
8A1, SPTM 6A2 or SPTM 6A3. When using
the measuring module SPTM 8A1 the control
module is able to measure three phase currents
and three phase-to-phase voltages. Active and
reactive power are measured via the mA inputs
and external measuring transducers.
When using the measuring module SPTM 6A2
the control module can measure three phase
currents and three phase-to-phase voltages. Ac-
tive and reactive power are measured using an
Aron connection and the internal current and
voltage signals of the module.
When using the measuring module SPTM 6A3
the control module can measure three phase
currents and three phase-to-phase voltages. Ac-
tive and reactive power are measured on the
basis of the internal voltage of the module and
two current signals. The voltage to be used and
the corresponding currents are selected with
switches.
The ratio of the primary current and voltage
transformers can be selected with the control
module. Based on these values the control mod-
ule is able to indicate the currents, voltages and
power as primary values. If the mA inputs are
used for power measurement, the mA signals
can be scaled as actual MW and Mvar values.
These primary values can be indicated locally
and, when needed, be transmitted to the higher-
level system over the SPA bus.
Active energy can be measured in two ways; by
calculating the value on the basis of the power
measured via one of the optional measuring
modules, SPTM 8A1, SPTM 6A2 or SPTM
6A3, or by employing input channel 11 as a
pulse counter input. In the latter case an external
energy meter with pulse output is needed. In
both cases the amount of measured energy can
be displayed locally and transmitted to the re-
mote control system over the SPA bus.
Measurement
functions
The feeder terminal includes two serial commu-
nication ports, one on the front panel and the
other on the rear panel.
The 9-pole RS 232 connection on the front
panel is intended for the connection of a PC to
be used for setting the CB/disconnector con-
figuration, feeder oriented interlocking and other
parameters of the control module with a PC.
The 9-pole RS 485 connection on the rear panel
is used to connect the feeder terminal to the SPA
bus via an interface module type SPA-ZC17_ or
SPA-ZC21_.
Serial
communication
Auxiliary power
supply
For its operation the feeder terminal requires a
secured auxiliary voltage supply. The feeder
terminal’s internal power supply module SPGU
240A1 or SPGU 48B2 forms the voltages re-
quired by the measuring relay modules, the
control module and the input / output modules.
The power supply module is a transformer con-
nected, i.e. galvanically isolated primary and
secondary side, flyback-type DC/DC converter.
The primary side of the power supply module is
protected with a fuse, F1, located on the PCB of
the module. The fuse size is 1 A (slow).
A green LED indicator U
aux
on the front panel
is lit when the power supply module is in opera-
tion. There are two versions of power supply
modules available. The secondary sides of the
modules are identical, but the input voltage
range is different. The input voltage range is
marked on the front panel of the control mod-
ule.
