ENA-NXG is based on modular architecture, allowing combination of one CPU module and up to six selected input modules into one meter. The input modules are providing input signal isolation, filtering and A/D conversion, sending the data using digital backplane bus. The CPU module is equipped with FPGA receiving all digital input data, and the real-time controller running meter firmware and providing all interfaces and data storage.

Resulting meter functionality is based on the selected input module type and count, and on the meter firmware.


Power Quality (PQ)

The firmware calculates power quality parameters according EN50160 fully follows requirements described in IEC 61000-4-30 Class A and others (61000-4-7, 61000-4-15)

Main measurement functions are:

  • U, I, P, Q, S, frequency, THD U, THD I, power factor, energies – AP, AQ, AS, APin, APout, all quantities are per phase and total
  • Harmonics – U and I, up to 50, optionally also power harmonics
  • All quantitates are calculated on 200 ms (10/12 period basis) according to IEC 61000-4-30
  • Voltage quality according to EN50160, IEC 61000-4-30 Class A (U, freq., THD U, flicker, unbalance, harmonics)
  • Voltage events according EN50160, IEC 61000-4-30 Class A (dip, swell, interruption – time, extrema, length)
  • Waveform capture – in case of trigger, the device captures the waveform
    • Trigger can be activated by selected quantities (U, I, P, Q, S, freq., PF) crosses specified limits
    • Waveform means raw voltage/current signal with sampling rate at 128 samples/period, waveform length is 20 periods
    • Waveforms are stored in files in standard protocol and the device is able to hold at least 100 of them in local storage
  • Data are provided in two ways:
    • Real-time – using standard protocol (MODBUS), refreshed every 200 ms, all above mentioned quantitates
    • Historical – the device calculate (gapless) true RMS/average of all above quantities in user pre-defined interval, for example 1 minute and store these data in files in standard protocol (comma/tab separated txt file). The device is able to hold these data/files for 12 month at minimum in local storage (SD card). The historical data also includes voltage events details according to EN50160.

ENA NXG 3web


Phasor Measurement (PMU)

PMU - Phasor Measurement Unit is a device for accurate synchrophasor measurements.

The measurement results are used for on-line detection of electrical grid status based on comparing the phase angle of the fundamental harmonic measured at different points of the distribution or transmission network using several devices in synchronized points in time. The meter has to be equipped by the internal/external GPS for receiving synchronizing timestamps.

The PMU firmware measures voltage and current phasors (with a Total Vector Error less than 0.5 %), frequency, calculates the positive symmetrical components of voltages and currents. It can apply measuring transformers error correction. The measured data is sent to the superior system according to the IEEE C37.118-2005 communication protocol. By default, the device fully complies with the requirements of IEEE C37.118-2005, which defines PMU accuracy in stabilized state and a communication protocol for real-time phasor transmission.


Feeder Monitoring (MFM)

Meter input modules can be combined in a way of measuring one 3-phase voltage and multiple 3-phase current systems. The intention of such meter is typically to monitor the distribution transformer powering multiple output feeders.

Functionality of multi-feeder-monitor is similar to PQ meter, with possibility to measure up to 10 3-phase feeders in total. Multi feeder monitor also provides detailed information about power and energy consumption of each feeder.


Mixed/Custom Functionality

The ENA-NXG is an open hardware and software platform. It allows mix of different input modules count and type, allowing to build device following end user needs. Also the firmware functionality can be prepared as a mix of above mentioned functions, and additional user requirements can be applied into the firmware.

In special cases ENA-NXG platform can be provided as open OEM system with set of development examples for customer’s own development.



ENA-NXG-CPU.A CPU module based on NI-SOM (667 MHz dual-core, FPGA, real-time OS, NI LabVIEW) with 8-32 GB SD card, Ethernet, serial port, USB for data download and direct PC connection, 24 V DC power is required
ENA-NXG-CPU.B ENA-NXG-CPU.A extended with integrated GPS receiver
ENA-NXG-CPU.C ENA-NXG-CPU.A extended with fiber optic interface for ENA-TIR (ENA-TIR is external GPS receiver)
Input Modules
All analog input modules are providing 24 bit sigma-delta A/D conversion
ENA-NXG-HVI.A 4 channel high voltage input module, 300 V RMS range (measuring up to 600 V RMS), 16/32 kSa/ch., 6 kV isolation
Used for direct voltage measurement
ENA-NXG-HVI.B ENA-NXG-HVI.A with additional 4 low voltage input channels, 1 V RMS range, 2.5 kV isolation
Additional inputs are used for indirect current measurement using XX Amp / 0.33 V CTs
This single module can cover one 3-phase system (4V, 4I)
ENA-NXG-LVI.A 16 channel low voltage input module, 1V RMS range, 16 kSa/ch.
2 channels can be switched to temperature measurement / PT1000
Used for indirect current measurement (XX Amp / 0.33 V CTs)
ENA-NXG-LVI.B 8 channel low voltage input module, 1 V RMS range, 16 kSa/ch.
Used for indirect current measurement (XX Amp / 0.33 V CTs)
ENA-NXG-HCI.A 4 channel current input module, 1 A RMS range, 16 kSa/ch.
Used for indirect current measurement (XX Amp / 1 A CTs)
ENA-NXG-HCI.B 4 channel current input module, 5 A RMS range, 16 kSa/ch.
Used for indirect current measurement (XX Amp / 5 A CTs)
ENA-NXG-DI 16 channel digital input module