Secondary Substation Connection - Challenges and Solutions

The automation of primary and secondary distribution substations is the most challenging activity when it comes to developing a smart grid.
Published: Wed 05 Feb 2014

The utility industry experiences many challenges when it comes to balancing high energy demand with low energy generation.This has led to grid modernisation and increased adoption of smart devices such as synchrophasors, sensors, smart meters, and actuators which provide real-time assessment of power-system health and control of utility assets like transformers and capacitor banks.

The main reason why the automation of primary and secondary substations is challenging is because distribution substations are distributed across a wide area.

Jyrki Penttonen, CEO, Viola Systems, explains in his prersentation, Practical Techniques for Improving Efficiency in Transmission and Distribution Networks that the connection of secondary substations is more complicated because of their large numbers. Secondary substations must be wirelessly controlled and monitored and to arrange this automation can pose can number of complex challenges:

  • Communication with the nodes-Traditional methods in communicating to primary substations will not work with secondary stations as the scale is larger. Only wireless technologies can be considered.

  • Minimisation of engineering and planning efforts-Due to the large number of substations, costs and planning efforts must be reduced to ensure project viability.

  • Implementation of technology-The technology solutions in primary substations cannot be adapted for secondary substation usage as it will become expensive. Low cost hardware solutions are needed to ensure commercial viability.

  • Cyber security-Connection of these secondary substations leaves infrastructure vulnerable. Solutions must be developed to avoid security threats.

  • Integration to SCADA

Successful solutions for the connection of secondary connections include:

  • Intelligent control cabinets are created for switchgear control, MV fault indication, LV metering, condition monitoring, and integrated communication. These solutions are prefabricated and preconfigured so there will be no need for assembling.

  • Integrated connectivity has been developed for the above listed control cabinets. This facility, which establishes a virtual private network connection will-is connected to the SCADA center, with maximum cyber security. Servers are being deployed in central locations so that it is possible to facilitate a connection endpoint.

  • In this cloud, various tools will be able to manage secondary substations effectively. This includes cyber security, user interface for Intelligent Electronic Device control, monitoring and controlling interface for communication network, and SCADA integration. The firm also provides technology to provide complex reports about power flows.

According to Mr Penttone, the market needs the following in order to realise the successful connection of secondary substations:

  • Standardised automation packages with built-in applications as this reduces engineering and installation work. These are prefabricated and preconfigured.

  • Integrated wireless communication for real time visibility (end to end connectivity)

  • Cloud remote commissioning tools should be easy to deploy; and

  • Inbuilt drivers and protocols for connecting different protocols should include total integrated solutions.

The secondary substation occupies an ideal position in the grid network as it handles distributed grid management functions. This is done through a substation node that aggregates different communication technologies to orchestrate activities of the Intelligent Electronic Devices in substation, distributed energy resources, and smart meters.

Further Reading

Engerati: Practical techniques for improving efficiency in Transmission & Distribution networks