Sensor proliferation is a common occurrence in modern distribution switchgear evolution. The latest generation of Protection Relays, Controllers and even standalone protection devices boast an ever-growing myriad of sensor capabilities. With the rapid pace of integration of additional sensors in the growing network of intelligent electricity utility distribution assets, it is a challenge to stay up to date with the motivations behind the adoption of new functions. Whilst some of these features have more merit than others, a recent addition to distribution switchgear which is rising in popularity is the inclusion of GPS in Automatic Circuit Reclosers (ACRs).
Automatic Circuit Reclosers are today typically characterised as outdoor pole-top circuit breakers with advanced microcontroller based control systems. These integrated systems boast astonishing capability and complexity, and the latest advent of onboard GPS augments the already impressive list of features. It does however beg the question, “Why would you need a GPS tracker on a device that is permanently installed in a stationary location?”
Firstly, GPS has been a mainstay in substation installations in the form of a central GPS clock. Time, and timestamp synchronisation across multiple intelligent utility devices is imperative for effective post-fault analysis. Traditional SCADA time synchronisation techniques do not always provide accuracy below 1 second, particularly when the latency to various devices on a utility network is uneven. For protection engineering, the modus operandi is well within the millisecond or even microsecond range. GPS time synchronisation provides the level of accuracy for timestamping that is far beyond the capability of conventional time sync techniques.
Secondly, GPS allows for time synchronisation when communications are lost. For remote switchgear installations which may be without communications or with poor connectivity, GPS allows for time synchronisation independent of centralised communications. This feature also gives the remote devices the ability to combat clock drift even when the link to the control centre is tenuous at best.
Another common application is for the benefit of managing centralised control. Engineering Access, or the ability to remotely login to the control system of an outdoor field switchgear is emerging as a highly successful method of reducing network operating costs. Logging in remotely can save on field operative expenses such as dispatching teams for minor settings changes and data gathering, but the operational security of such a system requires special consideration. When remotely logging into a device, being able to confirm device location provides peace of mind that engineers are in fact communicating with the device they think they are, mitigating the risk of a sending wrong settings to a device.
In consideration of Distribution Automation, Recloser GPS co-ordinates are also highly valuable when integrating into mapping into automatic dispatch systems or Fault Location Isolation Restoration (FLIR) automation systems.
Lastly, new distribution protection techniques such as synchrophasors are gaining popularity within the utility engineering fraternity. Functions such as this requires microsecond accuracy for timing, making GPS an absolute necessity to gain the accuracy required. Utilities who are seeking to future proof their assets are entering GPS as a standard requirement, regardless of whether the feature is in use immediately. With the evolving needs of managing smart grids, distributed generation proliferation and integration of renewables, high accuracy protection will almost certainly be required for the network of the future.
“In today’s connected world it makes sense for your recloser to be able to tell you its installation location when you power it up,” says NOJA Power Group Managing Director Neil O’Sullivan.
NOJA Power is no exception to the implementation of this capability. The NOJA Power OSM Recloser System with RC15 Control is one of the industry leaders in GPS technology. The inclusion of GPS as a standard feature in this system has been eagerly deployed around the globe, as utilities improve their protection, post fault analysis and remote management of their assets.
To learn more about NOJA Power, the OSM Range of Automatic Circuit Reclosers and Control Systems, visit www.nojapower.co.za