Power quality analyzer cl. A PLA44

Power quality analyzers is designed according to the norm IEC 61000-4-30 cl. A ed. 3 for continuous measurement of electrical parameters in LV and MV systems for further power quality investigation. The PLA44 is built with a powerful RISC processor that provides sufficient processing capabilities for real-time measurement and calculation of all parameters and values.

Continuous sampling of the voltage and current inputs at 40 kHz, guarantees the highest accuracy. The PLA44 is the instrument for power quality monitoring according to EN 50160 of the incoming energy supply side as well as on the consumer side in order to find and analyse the root cause of network problems.

U and I accuracy 0.1
sampling frequency 40 kHz
communication interfaces Ethernet, USB, RS485
communication protocols Modbus RTU, Modbus TCP, SNTP, SMTP, FTP, HTTP, MTP, MQTT
RS485 Modbus gateway
2 x digital I/O
4 voltage and 4 current inputs

measuring according IEC 61000-4-30 ed.3 cl. A
harmonics, interharmonics EN 61000-4-7 up to 64th
flicker EN 61000-4-15
suitable for PQ reports EN 50160
transient detection > 25 μs
events detection > 10 ms
avg, max, min recorded value
external temperature sensor

on board logging Flash memory 1GB
WWW-server and email notification
panel mounting design 144x144mm
PMS SW for configuration, monitoring and evaluation
MQTT support
PQDIF export
EN50160, PGC PQ logging

Function

Voltage and current signals are digitalized by high class A/D converter and computing with RISC microprocessor. Effective values are computed continuously in 200 ms (10 periods) windows. Independently on this computing is for events detection each 10 ms counted effective value of U and I. Another absolutely independent part is transient detection that are directly detected from samples of digitalized U and I.

IEC 61000-4-30 ed.3 cl. A

PQ analyzer PLA44 measures according the standard IEC 61000-4-30 ed. 3 class A. Such type of analyzers are used in applications where there is necessary precise measurement for power quality evaluation according norms EN 50160, EN 61000-4-7 and EN 61000-4-15. If two devices of class A measures the same signal of voltage and current, measurement results at the same moment have to be same with defined measurement uncertainty.

Events

Events are unexpected signal changes with duration from 10ms up to days. In some installations these events can cause material damages and economical lost. Norm EN 50160 defines limits of events and its quantity that can appear in electrical grid during a year. PQA PLA44 evaluates following type of events DIP, INT, SWELL, RVC and I_MAX.

Transients

Voltage transients are short commutation, impulse or oscillatory events in electrical grid. Their source can be inductive load switching, power factor correction instruments, atmospheric events, protection instruments action or malfunction of switching elements in the grid.

PLA44 analyser detects two types of transients. Absolute transients and differential transients.

• Absolute transients are detected according to override of defined voltage level. The trigger for detection of the absolute transients is defined by absolute threshold (percentage of Udin).

• Differential transients are detected according to the difference between two consecutive voltage measurements. The difference between measurement is defined by differential threshold (percentage of Udin).

WWW server

Device has embedded web server for remote monitoring of the PLA44 instrument over the Internet.

Software

Software PMS - Power Monitor System offers possibility for essential configuration of PLA44. More over it is a tool to define recording template, alarms, and defined events and transients limits for PQ evaluation. Another part of PMS SW is used for PQ evaluation and report generation.

MQTT

integration of this protocol into power quality analyser PLA44 allows implementation of instrument into any SW. Measured data are divided into several topics in which user can chose which one want to receive. Measured data are transferred in file format JSON.

Measured parameters

parameter	Range	Display	Accuracy
phase voltage	10...600 V	1 V...1 MV	0.1%
line-line voltage	18...1000 V	0...1 MV	0.1%
system frequency	40...70 Hz	40...70 Hz	10 mHz
current	0.001...8.5 A	1 mA...1 MA	0.1%
cosφ	0.01L...0.01C	0.01L...0.01C	1 %
power factor	0.01L...0.01C	0.01L...0.01C	1 %
THDU L-N	0...99.9%	0...999%	1 %
THDU L-L	0...99.9%	0...999%	1 %
THDI	0...99.9%	0...999%	1 %
U harmonicics	0...99.9%	0...999%	class 1
group of U interharmonics	0...99.9%	0...999%	class 1
group of U harmonics	0...99.9%	0...999%	class 1
P harmonics	0...99.9%	0...999%	class 1
Q harmonics	0...99.9%	0...999%	class 1
I harmonics	0...99.9%	0...999%	class 1
group of I interharmonics	0...99.9%	0...999%	class 1
group of I harmonics	0...99.9%	0...999%	class 1
short-term flicker	0.4...10.0	0.4...10.0	class A
long-term flicker	0.4...10.0	0.4...10.0	class A
under-voltage	0...100%	0...100%	0.2%
over-voltage	0...100%	0...100%	0.2%
asymmetry of voltage	0...100%	0...100%	0.15%
N wire voltage	10...600 V	0...1 MV	0.2%
K-factor
asymmetry of current			0.5%
PQ transients			25 μs
PQ events			10 ms
ripple control
active power	0...15.3 kW	0...999 GW	0.2%
reactive power	0...15.3 kvar	0...999 Gvar	0.2%
aparent power	0...15.3 kVA	0...999 GVA	0.2%
distortion power			0.2%
active energy +/-	0...999 GWh	0...999 GWh	class 0.5S
reactive L energy +/-	0...999 Gvarh	0...999 Gvarh	class 1
reactive C energy +/-	0...999 Gvarh	0...999 Gvarh	class 1
temperature			1°C

Technical features

Parameter	Value
auxiliary supply voltage	85 ... 250 VAC/DC (±10%) or 24 ... 60 VAC/DC (±10%)
self consumption	< 8 VA
time uncertinity	< 1 s a day
number of I/O	2
VT and CT ratio	1...750 000
sampling rate	40 kHz
event detection	> 10 ms
transient detection	> 25 μs
logger memory	1 GB flash
display	TFT VGA 5.6"
external temperature sensor	NTC 10 kΩ / 25°C
communication interfaces	RS485 / LAN / USB
communication protocols	Modbus RTU, Modbus TCP, SNTP, SMTP, HTTP, FTP, MTP, MQTT
ambient temperature	-25°C ... +70°C
dimensions	144 x 144 x 80 mm
weight	1350 g
protection degree	IP20 rear side / IP54 front panel
related standards	EN 61000-4-30 class A / EN 61000-4-7 / EN 61000-4-15 class A / EN 61557-12