Installation manual

UNIPOWER

Installation manual PQ Secure

I. The recorder has 4 differential Current channels (the range is stated on the label). The

current channels are designed for direct connection to the existing instrument transformer

(CT) secondary side. It is important to connect the current channels with the correct polarity;

otherwise the power charts displayed by the recorder will be incorrect. Connect the current

channels in accordance with the wiring diagrams later in this manual.

J. The recorder has 4 differential voltage inputs (the range is stated on the label). There are two

inputs for each channel, with polarities marked as plus (+) and minus (-). The voltage inputs

are designed for the direct measurement of line-to-neutral voltages in low voltage networks as

well as for connection to instrument transformers (PT) secondary circuit in high voltage

networks. Remember to connect the polarities correctly, because incorrect polarity on the

voltages channels will shift the voltage signal through 180°, affecting the power calculations.

Connect the voltage channels in accordance with the wiring diagrams later in this manual.

K. RJ-6/4 connection for communication with Internal modem, which is available as an option.

L. Ref/SENSE inputs (optional). Connect these inputs to an accurate voltage reference typical

the normal PT voltage output. The instrument will calibrate the standard voltage inputs

U1-U3 to the inputs L1-L3. U1-U3 can be any high bandwidth voltage signal without

absolute accuracy, for example a capacitive divider. When the meter is equipped with

Ref/SENSE calibration channel U4 is disabled.

Note: These inputs are related to ground (ref)!

5.4 Ref/SENSE Calibration (optional)

This function is typically used for accurate harmonic measurement. Standard PTs have limited

frequency response which makes the harmonic measurement less accurate. To overcome this

problem a capacitive divider or any type of high bandwidth signal can be used. Often there is a

temperature or impedance demand that might cause these high bandwidth signals to be less accurate.

To compensate for the error in the high bandwidth signal, three additional voltage inputs L1-L3 are

used. L1-L3 are connected to a more exact voltage reference like the signal from a standard PT.

5.4.1 Ref/SENSE Connection

Connect the output from a PT to L1 and enter the constants for the PT ration in PQOnline. Constant

U1. Connect the output from high bandwidth signal to U1 and enter the actual expected voltage of

this signal in PQOnline reference “U1-3 actual” (typical value is 63.5V). Make sure that L1 and U1

measure on the same phase. Repeat the steps for channel L2-U2 and L3-U3. The high bandwidth

signals will now be calibrated continuously to the accurate reference signal for each phase. This

means that all parameters measured will have an accurate reading.

5.5 Front panel

On the front panel is a USB connector for communication with external PC. There is also a green and

a red status LED. They have the following meaning:

Green

LED (left)

Red LED

(right)

Meaning