Power Quality Meters | GE Multilin PQMII-T20

GE Multilin PQMII-T20 Power Quality Meter

The GE Multilin PQMII-T20, also cataloged as the PQMII-T20-C-A Power Quality Meter, operates as a dedicated hardware component for power quality monitoring and feeder protection within electrical distribution networks. This panel-mounted digital unit samples three-phase voltage lines (100-480 VAC) and 1 A / 5 A current transformer (CT) inputs, calculating total harmonic distortion (THD), power factor, frequency, and active energy parameters in real time. The device coordinates waveform capture, sequence-of-events logging, four programmable output relays, four isolated analog outputs, and digital switch inputs to execute automated load shedding and alarm logic across SCADA and automation platforms.

Suffix Breakdown & Model Matrix

The PQMII base ordering matrix determines the hardware architecture, auxiliary power supply parameters, transducer outputs, and environmental options:

• PQMII: Base series designation for the GE Multilin Power Quality Meter.
• T20: Transducer output option code denoting four isolated 4-20 mA analog outputs and four programmable control relays.
• C: Optional internal conformal coating designation for corrosion and dust protection.
• A: Control power supply rating code (20-60 VDC or 20-48 VAC auxiliary power input).

Hardware Specifications

Backplane Bus Communication Velocity and Firmware Flash Compatibility

The PQMII-T20 integrates dual RS-485 serial interfaces and an optional Ethernet module to maintain deterministic data transmission across SCADA and network backbones without bottlenecking backplane bus communication velocity. Internal digital signal processors isolate analog 4-20 mA loops and field digital inputs, updating system registers continuously while suppressing high-frequency noise. The unit features built-in flash memory to maintain firmware flash compatibility across legacy Modbus RTU loops and modern DNP 3.0 master platforms, permitting remote configuration and synchronized event logs without interrupting active metering functions.

Frequently Asked Questions

Q: How do technicians perform firmware updates or access diagnostic logs on the PQMII-T20?

A: Connect a PC cable directly to the front RS-232 port or communicate remotely over Ethernet using Modbus TCP/IP. The device permits non-disruptive log retrieval and flash firmware maintenance while the primary monitoring loops remain energized.

Q: Can the 4-20 mA analog outputs be mapped directly to external PLC analog input modules?

A: Yes, all four onboard analog outputs are electrically isolated and user-assignable. Engineers map measured parameters such as current, voltage, active power, or THD directly to standard 4-20 mA channels for automation control.

Q: What grounding protocols apply when wiring the 1 A / 5 A CT secondary circuits?

A: Terminate all CT secondary wiring securely at the rear screw terminals and establish a solid, single-point ground connection on the secondary return circuit to prevent high-voltage induction or ground loop offsets.

Field Installation Guidelines

Panel Cutout and Mechanical Mounting: Insert the PQMII-T20 into the standard panel cutout, securing the side mounting brackets firmly to ensure a low-impedance connection between the metallic enclosure case and the switchgear cabinet chassis.

CT and VT Wiring Integrity: Wire the three-phase 100-480 VAC potential transformer (VT) inputs and 1 A / 5 A current transformer (CT) secondary loops using recommended wire gauges. Observe strict polarity markings to ensure correct power factor and directional power calculations.

Shielding and Communication Lines: Route RS-485 twisted-pair communication cables away from high-voltage busbars and motor control lines. Ground the RS-485 cable shield at one end only to prevent ground loop noise from corrupting Modbus or DNP 3.0 serial communications.