MicroLogic 5.0H and 6.0H Trip Units with Harmonic Metering

MicroLogic 6.0H Trip Unit

In addition to the P functions, the MicroLogic H trip units offer:

In-depth analysis of power quality including calculation of harmonics and the fundamentals.
Diagnostics aid and event analysis through waveform capture.
Customized alarm programming to analyze and track down a disturbance on the ac power system.
Systematic time stamping of all events and creation of logs.

Type of Measurement		Unit of Measurement	Measurement Source
Current	IRMS	A	ØA, ØB, ØC or N
	IAVERAGE	A	(ØA + ØB + ØC) / 3
	IPEAK/÷2	A	ØA, ØB, ØC or N
	IIMBALANCE	%	ØA, ØB, ØC or N
Voltage	VRMS	V	(ØA–ØB), (ØB–ØC) and (ØC–ØA)
	VRMS	V	(ØA–N), (ØB–N) and (ØC–N)
	VIMBALANCE	%	VRMS
Power	P, Q and S	W, VAR, VA	Total
	EP, EQ and ES	Wh, VARh, VAh	Total
	W, VAR, VA		Total
Frequency	F	Hz	ØA, ØB, or ØC
Power Quality Indicators	Fundamentals	50/60 Hz component	V, I, P, Q, and S
THD	THD	%	V/I
V and I harmonics	V and I harmonics	Amplitude to phase	1, 2, 3, 4...50

Demand Metering: Similar to the MicroLogic P trip unit, demand values are calculated over a fixed or sliding time window that can be set from five to 60 minutes.

Type of Measurement		Unit of Measurement	Measurement Source
Current	IDEMAND	A	ØA, ØB, ØC or N
Power	P, Q and SDEMAND	W, VAR, VA	Total

Waveform Capture

MicroLogic H trip units can capture and store current and voltage waveforms using digital sampling techniques similar to those used in oscilloscopes. Using the information available in the captured waveform, it is possible to determine the level of harmonics as well as the direction and amplitude of the flow of harmonic power.

Users of MicroLogic H trip units can record manually via the keypad the following waveforms:

The four currents: I_a, I_b, I_c, and I_N
The three phase-to-phase voltages: V_ab, V_bc, and V_ca

Waveforms may be displayed on the graphic screen of MicroLogic H trip units or communicated over a networked system. The recording takes place over one cycle with a measurement range of 0 to 1.5 I_N for current and 0 to 690 volts for voltage. The resolution is sixty-four points per cycle.

Customized Alarm Programming

The instantaneous value of each measurement can be compared to user-set high and low thresholds. Overrun of a threshold generates an alarm. Programmable action can be linked to each alarm, including

Harmonic Trip Unit Event Log

Each event is recorded with:

The date, time, and name of the event.
The event characteristics.