Smart farms: Avoiding power quality issues with automated systems
However, automation technologies form a critical part of modern livestock and farm management systems. Many farmers though, especially those operating small and medium sized farms, might be overlooking a critical aspect of power quality in their automated livestock farming systems.
The smart agriculture market is currently growing at a compound annual growth rate (CAGR) of 13.8 per cent and is expected to be worth $18.45 Billion by 2022, according to research firm MarketsandMarkets. The main factors driving growth include an increased adoption of technology in agriculture generally, a higher demand for food globally and assistance in monitoring livestock performance and health.
The types of automation technologies farmers now use is hugely varied, ranging from automatic feed control, milking systems, electronic identification and herd tracking, automatic drafting and gate control as well as in all areas of health, treatment, breeding and farm maintenance.
These complex systems, made up of IoT sensor-enabled devices connected to industrial computing systems provide a wealth of data for farmers to maintain the welfare of their animals while maximising yield.
Automatic milking
Take automatic milking systems in the dairy industry for example. Here, radio frequency identification (RFID) tags are attached to a cow’s ears. Used in everything from warehousing and logistics to fridges and washing machines, RFID tags have found a useful home in the farming sector where the RFID tag communicates with a base station to provide an up to date location for each animal.
As the cow is drafted in for milking, the system logs the cow’s identity and, as the robotic milking system automatically begins to milk the cow, it continues to track real time yield against a historical record, which is then used to tailor the cow’s feed characteristics.
The data generated from an entire herd is sent to a centralised system where a single farmer overseeing the entire process can manipulate the data to forecast trends relating to yield, feed demand, breeding and medical treatment, among other things, to make informed decisions on best practice. This level of traceability afforded by smart systems is helping the farming industry to overcome years of stigma associated with many high profile incidents such as the horsemeat scandal of 2013.
However, despite the benefits provided by all of this big data, the rising complexity of automated systems is resulting in power quality problems for many farmers. Automatic milking systems for example are made up of a large network of motors, actuators, pumps and variable speed drives (VSDs), often connected using miles of power cables on a commercial farm.
These networks typically use power line communication (PLC) otherwise known as ripple control technology. Power line communication offers a cheap and readily available method of using the same electricity grids and power cables to transmit data. It is typically used to control smart meters, street lighting and Wi-Fi range extenders.
The problem is that this is a very inefficient transmission that results in high levels of mains and airborne sources of electromagnetic interference (EMI) and radio frequency interference (RFI). Combine this with inadequately earthed equipment, often installed in close proximity, and it’s not difficult to see why many highly automated farming systems are plagued with power quality problems.
What’s worse is that typical output mains filters designed to eliminate electromagnetic compatibility (EMC) problems are simply not effective for networks that employ power line communication.
For example, one of our customers, who is a large US-based manufacturer, was using tagging in its automated milking systems. During routine operation, the company was facing a variety of electromagnetic and radio-frequency interference (EMI/RFI) issues and couldn’t quite figure out what was causing the problem. They had tried everything from using EMC filters on the input and output to their variable speed drives as well as reconfiguring the system to try to eliminate these problems.
It wasn’t until a REO engineer suggested that they try using a power line communication filter, that the problem was solved. The company subsequently eliminated its power quality issues and made efficiency and operational gains as a result.
For these applications, farmers should consider dedicated PLC filters such as REO’s CNW163, a 16A power line communication filter designed to filter wide ranging signal frequencies from 50 kHz to 20 MHz, a vital feature when you consider that there is no global standard for PLC whose operating frequencies can range from 95-148.5 kHz for European applications.
By carefully considering ways of eliminating power quality problems in their smart farming applications, farmers can continue to enjoy the benefits of automated farming technologies without any of the downsides. Perhaps then farmers can truly embrace buzzwords such as big data, industry 4.0 and the Internet of Things.
About the author:
Steve Hughes is managing director of power quality specialist REO UK – www.reo.co.uk
