Power quality in low voltage areas

The Netherlands’ energy transition relies on sophisticated remote telemetry systems.

“While God created the Earth, the Dutch created the Netherlands,” goes the old saying — referring to how the country’s first settlers from around 400 BCE built the country from earth mounds and dikes to hold back the waters of the North Sea. Now, the country is building a smart grid infrastructure to move away from traditional energy sources to renewables. To overcome the challenges of monitoring these medium-voltage renewable energy sources, smart grid operator Juva turned to Ovarro, the specialist in remote telemetry solutions.

Transitioning to a low carbon energy system is now the primary focus of Dutch energy policy, according to the International Energy Agency. The Netherlands’ 2019 Climate Act has set legally-binding targets to reduce greenhouse gas (GHG) emissions by 2050. First, to reduce emissions to 95 per cent compared with 1990’s levels and, second, for 100 per cent of electricity to come from renewables by that year.

As reported by Reuters, the country also faces pressure to bring its end date forward to 2030 following COP26. Wind, wave, marine, hydro, biomass and solar are all proving themselves as viable alternative energy sources — but finding the right control technology to monitor these sources effectively presents a challenge for smart grid operators.

Effectively managing assets on a smart grid is only achievable through the capture, storage and interpretation of vast amounts of data from physical assets. However, renewable energy sources like solar rely on low- or medium-voltages, and monitoring these can be more challenging. Renewable sources are unpredictable. For instance, because the sun shines at certain times, solar panels feed energy back into to the grid periodically which can lead to potential instabilities and disruptions in the grid. What’s more, conventional remote monitoring systems — aside from being expensive — can be ill-suited to the task of properly interpreting the fluctuating performance data.

These were the challenges faced by Juva, an energy network management company that works together with the grid operator Westland Infra on distribution automation. Together, they manage a smart grid covering an area of 25 to 30 square kilometres in Westland, the Netherlands, which involves monitoring around 250  substations in the region. Juva sought a better solution for remote monitoring and managing low- and medium-voltages on the grid.

This need was getting bigger as more and more Dutch homes turn to renewable energy sources, like solar panels. Whereas photovoltaic systems accounted for just 0.05 per cent, or 56 gigawatt hours (GWh), of the Netherlands’ total energy consumption ten years ago, this figure had risen to 6.79 per cent or 8,144 GWh by 2020.

Outside the box

“We needed a flexible, customisable solution to handle the requirements typical of low- or medium-voltage networks,” says Roel van de Konijnenburg, operations technology specialist at Juva. “We found that monitoring and control technology platforms from other suppliers tend to focus on a standard template.

Juva was facing limitations with its existing systems. Changes to drives and operating systems were time-consuming and could be difficult to implement. Instead, Juva wanted a solution that would go beyond the normal boundaries — that was secure, cost-effective and could handle the unpredictable behaviours of renewable energy sources. Fortunately, it had a partner in mind.

“Ovarro has worked with Juva for many years,” says Ronald Robbertsen, a project engineer at Ovarro who specialises in configuring and implementing medium-voltage network telemetry solutions for grid operators. “We have worked together on all kinds of projects including for the monitoring and controlling of protection relays, energy meters and remote switching of medium-voltage fields.”

“We turned to Ovarro because they’re really flexible with implementation,” says Konijnenburg. “It’s easier to work with them, as a result.”

A consistent supply

To investigate how to implement a consistent medium-voltage energy supply cross the smart grid, Juva and Ovarro examined some of the key issues. That included issues relative to the three-phase grid, which is the world’s most common and economical way of alternating current power generation, transmission and distribution across a network.

Robbertsen says, “The customer saw that the low-voltage solar panels of various households in a neighbourhood were not equally distributed over the three-phase grid. In another instance, a wire in the cable was overloaded due to the high level of sunlight. Juva needed a solution with flexibility to detect these unique instances, and its existing hardware also made it difficult to detect instances of illegal energy use.”

Ovarro had to offer a solution that would help Juva manage its grid productivity, energy-efficiency and security with higher levels of quality of service (QoS). To achieve this, it paired-up with Eneida, which specialises in specially-designed smart sensor networks, data analytics and unique collaborative software to better analyse and control data on grids.

Ovarro devised a solution with Rogowski coils. Rogowski coils are commonly used to accurately monitor medium- and low-voltages in precision welding systems, arc melting furnaces, in short-circuit testing of electric generators and as sensors in protection systems of electrical plants.

“With this solution,” explains Robbertsen, “the installation time is reduced to less than 30 minutes to measure eight fields. Moreover the purchase price is much cheaper than those conventional solutions.”

Aside from the Rogowski coils, RTU systems were needed for the capture, storage and interpretation of vast amounts of data from physical assets in the network. RTUs are now a critical part of most power generation and distribution operations, and are essential for today and tomorrow’s smart grids. For Juva, Ovarro recommended the Datawatt Smart Grid (DSG) series which is designed for operation in the water, energy and industrial markets. The design operates under two main principles: flexibility and maximum security.

Flexibility and security

Flexible characteristics of the DSG include its ability to implement a variety of protocols in real-time including IEC104, COAP and Modbus, with other protocols available on request. New protocols can be created easily through the Linux operating platform and C# programming language, while programmable logic controller (PLC) programs can also be made with the latest standard from Codesys based on IEC61131-3 — this standard is the industrial protocol for control programs and is used by many national and international organisations and companies.

The DSG system greatly benefits the overall security of the network, adds Konijnenburg: “The hardware and software of DSG is a definite improvement. You can connect multiple networks in a station — one port is used for communications upwards and another for substation communications. We use a lot of firewall functions to protect these many inputs/outputs (I/Os). The security options aren’t limitless, but there are many.”

Meanwhile, Juva and Ovarro are also working on two pilot projects together. The first examines the Eneida system connected to the DSG, through which it is possible to monitor energy values in the area, such as from solar panels. For the second project, Ovarro is building Juva a steel cabinet with electrical components that can be placed outside to withstand temperature and weather changes.

“The cabinet has remote maintenance features that provide support when we don’t have many people in the field,” explains Konijnenburg. “So our engineers don’t have to drive out to a station every time there’s a fault. Instead, the problem can be monitored and managed through telemetry software in real-time from computer screen in the office. By always communicating data back to the DSG system, the cabinet can be the brains of any station in the smart grid.”

These technologies will prove vital as more homes and businesses in the Netherlands turn to low- and medium-voltage renewable energy sources, and as Juva expands its smart grid and the number of substations beyond the 250 it monitors currently. Just as the Dutch created the Netherlands all those years ago, the country is now on its way to creating a fully-sustainable energy grid by 2050 — if not sooner.