Testing and measurement equipment for smart metering

Smart meter is one of the advancements to the grid systems, and is common form of a grid technology. It’s primarily monitors and records your electrical consumption, digitally. As an attempt to minimise the power consumption, India is chalking out plan to install smart meters in every single house hold and commercial premises.

Infrastructural scope in testing programme
Smart metering infrastructure testing program includes various test instruments, such as signal analyser, spectrum analyser, protocol analyser o cable analyser, EMI EMC test of the meter and modules installed inside smart meter.

A signal analyser is based on a sweep type spectrum analyser that installs carious options, supports varied measurements to cater to the customers requirements. It further evaluates Wireless modules TX and RX characters. For instance, using the MX268017A Vector modulation analysis software for TX tests, supports modulation analysis Wi-SUN devices. Moreover, its functions permits observation of changes in the TX signal spectrum, in time domain. They play a significant role in understating and evaluating changes in the spectrum of burst signals sent especially from Wi-SUN devices. Since the TX signals from Wi-SUN can be restored, one can perform a protocol analysis using the saved data.

Cables, connectors must be of high quality and immune to RF EMI EMC interference. Similar enclosure where all electronics lies must be tested well and must be sure. Various environmental testing are also performed for individual modules and entire meter which includes temperature, humidity, vibration etc. testing. Products life cycle, MTTB testing are also performed at various stages to ensure good quality finished product.

Standard assessments for smart meters
Anritsu offer MS2830A Signal Analyser/ Spectrum Analyser which support smart meter testing. Testing is carried with help of software (installed on PC) that supports use of a signal analyser for evaluating the PHY layer (802.15.4g PHY) of Smart Utility Network wireless communications (Wi-SUN). The signal analyser is controlled by remote commands from this PC software to perform efficient RF tests of Wi-SUN devices, showing its usefulness in improving R&D efficiency.

Wi-SUN PHY measurement software in smart meters, remotely controls the signal analyser connected to the PC via a USB cable. This software requires the following tests:

Wi-SUN PHY Transmitter Test
Wi-SUN PHY TX tests quality modulation Where the two quality parameters specified in the FSK modulation EYE diagram, are measured to evaluate whether the quality falls within the standards or not. Also checks whether the frequency deviation error and zero crossing offset are within the permissible range, or, aren’t specified.

• Transmitter frequency offset – the offset of specified transmission frequency is measured to evaluate whether it is within the range or not.
• Transmitter adjacent channel power ration – The leakage power at 4 points adjacent to the specified channel is measured to evaluate and keep it within the specified range.
• Test Vectors – Frames are analysed to evaluate if it is framed in the designed format.

Wi-SUN PHY Receiver Test
Receiver sensitivity test and the Packet test – The RX sensitivity is tested and are evaluated under the (PER measurement). The specified number of packets (tested at a frame size of 20 octets) are output from the vector signal generator at the specified output level. On successful transmission, receipt of the packets by the Wi-SUN device is confirmed and the results are further added to the software.

Suggested advanced techniques
There must be sufficient R&D facility or common test lab for smart meter testing. These labs may be spread across country for faster response. Testing instruments like signal analyser or spectrum analyser must be able to test in lesser time to improve efficient during R&D and production. At the same time measuring instrument must be scale for other supported technologies.

Article  by:

Madhukar Tripathi
Anritsu India Pvt Ltd
M: +91 9310666466