The Metropolitan Electricity Authority (MEA) is a Distribution Network Operator (DNO) in Thailand, operating across the Bangkok metropolitan region.

As part of a strategy to upgrade its infrastructure, MEA planned to replace its overhead switches to improve the efficiency of its overhead network, reduce supply interruptions and enhance the quality of supply to MEA’s customers. This project contributes towards the company’s ultimate aim of automating its network to improve its overall efficiency and effectiveness.

The challenge

The project scope was to deliver a full turnkey solution replacing the existing overhead load break switches with new switches and adding integrated remote terminal units (RTU) to enable faster fault resolution.

The new equipment would need to operate under challenging local climactic conditions (high ambient temperatures and humidity) and meet MEA’s stringent cyber security requirements by using enhanced communications security protocols.

The Gemini 3 RTU, developed in the UK, would require customising by Lucy Electric’s local automation team in Thailand to suit MEA’s application and requirements.

The solution

Lucy Electric was able to provide a fully engineered, bespoke solution, supplying and installing 1800 GX overhead switches with integral Gemini 3 RTU. The unique modular design of the latest generation Gemini 3 provides a highly flexible platform for advanced feeder automation. Using a range of plug-in modules, the unit can be configured to work as a simple monitoring-only device or scaled-up to a sophisticated HV multi-switch controller, and anything in between.

The Gemini 3 RTUs were configured to be able to automatically transfer the power source for the overhead network using the international standard IEC 61499 programming language for distributed systems.

This ensures that supply can be automatically switched from one circuit to another so under fault conditions the network can reconfigure itself to maintain supply. This is a unique feature given the majority of the network in the city is on overhead lines.

The RTUs were also able to monitor key power, temperature and humidity measures to ensure network resilience can be maintained.

Due to the climatic conditions a high temperature NiMH battery was fitted. This is suited to standby power applications whilst also able to deliver enough power to operate the overhead switch in the absence of line voltage. The RTU ran Lucy Electric’s temperature compensated intelligent charging algorithm to maximise the service life of the battery. This is the first load break switch supplied to MEA with an advanced RTU incorporating high temperature batteries and automatic battery testing.

The equipment was supplied with DNP 3 secure protocols to deliver the enhanced security levels requested by the client. DNP 3 secure authentication allows the Gemini 3 RTU and MEA’s SCADA to unambiguously determine if they are communicating with each other. This provides a safeguard, ensuring the Gemini 3 RTU has verified that the command to operate the GX Load Break Switch has come from the SCADA. This is in addition to the standard “select-before-operate” control procedure.

The outcome

Lucy Electric successfully provided a flexible, secure solution which delivered on the company’s objectives of upgrading the network to improve its overall efficiency.

The built-in circuit switching protocols will allow automatic reconfiguration to ensure power supplies are maintained, significantly improving the overall customer experience. Bangkok residents and businesses can look forward to consistent and reliable power supply in the future.

The design of the installed Gemini 3 RTUs is future-proofed to meet customers’ evolving needs as it can be upgraded with new modules, without the need to recalibrate. This gives MEA the flexibility to add further functionality in the future as network and customer needs evolve.

Alongside this enhancements to communications security protocols fully met the highest cyber security protocols required by the company.

Commenting on the successful completion of the project, Sombat Jungkrajung, Director of Distribution Equipment Department, MEA, said

Lucy Electric proved an excellent partner, providing us with the deep technical knowledge, equipment tailored to our requirements and excellent project management which made it possible for us to future-proof our network for the benefit of customers.

Carl Sellick, Lucy Electric Regional MD, added

This is the next stage in our successful relationship with MEA. Our project engineers have been able to add value to the project by developing solutions which not only meet the needs of MEA’s customers today but provide a simple and flexible upgrade route as customer and network needs change. This is particularly important in high density population areas where future upgrades need to be carried out with minimal disruption.