engineering intelligent solutions

Case Study: St Kitts Electricity Company

St. Kitts, a Caribbean island, currently relies almost entirely on diesel for electricity generation, leaving it vulnerable to global oil price variations that directly impact the cost of electricity.

The island’s electrical power generation, transmission, distribution and retail are provided by the St. Kitts Electricity Company (SKELEC), a public utility company. At present, SKELEC has one power station with a total capacity of approximately of 43 MW, to service a peak demand of approximately 24 MW and a base SKELEC, together with the St Kitts’ Government, aims to shift away from diesel powered electricity to more sustainable sources of energy.

 

The Customer

As an island nation, it has the opportunity to take advantage of renewable sources such as tidal and off-shore wind, as well as geothermal and solar. Using these energy sources will create a more diversified energy mix, meaning the company, and its customers, are less likely  to be impacted by unpredictable fluctuations in oil price. 

 

The Challenge

The economic growth and development of a country depends substantially on the reliability of its electrical power supply.  Furthermore, the growth of embedded renewable generation brings its own challenges, including lower voltage generation, changes in power flow, and changes in supply and demand.

SKELEC identified that a network management system comprising a SCADA Control Centre and Remote Terminal Units (RTUs) installed throughout the electrical network in secondary switching stations, would prepare the utility to embrace future challenges. The new system would enable the transfer of real-time data using standard communications protocols and enable instantaneous remote control and state monitoring of the overall grid. 

It would also would allow the company to proactively manage the increase in variable load caused by different sources, in real-time, and support the implementation of an ongoing smart grid project, including efficient smart metering and smart electricity utilisation.

Moving to a fully remote-automated system was a big step for SKELEC, since only a small number of its switching substations contained locally automated switchgear; the majority were manual.

Lucy Electric’s goal was to create a bespoke network management solution, flexible enough to integrate into SKELEC’s ongoing smart grid project. The solution comprised a robust SCADA Control Centre to control and monitor the primary power station including the 10 generators and the vital secondary switching substations, through a secure communications architecture.

 

The Solution

Lucy Electric’s solution was implemented over a two year period and included the following elements:

  • Build the SCADA server and Control Centre rooms in SKELEC premises, scoping the civil work and designing the necessary SCADA interface infrastructure at the first stage

  • Develop an in-depth understanding of the specifics of the power station’s electrical operation and electrical circuit drawings for the generators and feeder bays

  • Define and establish a reliable and fast communication system between the existing power station Protection relays (IEDs) and the SCADA server room

  • Develop the SCADA system to allow the real-time control and monitoring of the entire power station

  • Develop and provide a DMS system with the geographical topology of the controlled electrical network

  • Define and establish a dual redundant SCADA LAN between the Control Centre and server room, and provide remote access throughout VPN tunneling and firewall gateways - Understand the SKELEC distribution network in terms of network operation and protection selectivity

  • Deep survey each secondary substation in terms of premise conditions, location, existing electrical switchgear, local field operations and available communication coverage

  • Define and establish the secondary (backhaul) communication system between the secondary switching substations and the SCADA server room using public GPRS and broadband service providers and dynamic IP’s via VPN tunneling and firewall secured polices

  • Establish the primary communication system  between the secondary switching substations and the SCADA server room using the SKELEC’s smart grid communication link 

  • Develop the SCADA system and databases to allow real-time control and monitoring of the vital secondary switching substation

  • Field installation of new SF6 Lucy Electric automated Ring Main Units (RMUs) and retrofit kits at the vital secondary switching substations

  • Field installation of new Lucy Electric Gemini RTUs, and set up of the primary and secondary communications medium to SCADA

  • Provide factory and site acceptance tests throughout all stages of the project Lucy Electric successfully met SKELEC’s expectations by providing an overall distribution management system as show in figure 1 (below). The technical solution was designed to be interoperable with the third party smart grid project, and the first step towards developing a fully advanced DMS system in future

  • Overcoming the technical and environmental challenges


During commissioning, hot and humid weather conditions were a daily challenge for the teams, with temperatures of 50 degrees Celsius common at the substation sites. Lucy Electric switchgear and RTUs were specified to meet these challenging environmental conditions and operated effectively despite the high humidity and temperatures.

The smooth running and delivery of the project was largely down to Lucy Electric maintaining a very positive working relationship with the SKELEC team. Over the course of the project the team built up trust with the client by consistently delivering the project to plan. When any issues were encountered, be they technical or operational, SKELEC and Lucy Electric were able to resolve them by working together.

A further complication was that during all stages of the project, Lucy Electric, in consultation with SKELEC, had to deploy the solution under live operating conditions in order to minimise the impact on SKELEC’s daily network operations. Additionally owing to the criticality and redundancy of the Distribution Network and tight implementation schedule constraints, a comprehensive, structured and detailed outage plan had to be created.  

  

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