​Network Resilience

Network Resilience

The investment in our network over the last 20 years has resulted in continuity of supply to our customers improving by more than 60%.

As our climate continues to change we must ensure that we continue to invest in making our network resilient to the changing weather patterns and more intense storms that we have seen over recent years.

Strong and reliable service

We must also ensure that our network is resilient enough to support our customers who will be using more electricity as they electrify heat and transport in their personal lives to support Ireland’s journey towards a clean energy system. Our network must be reliable and have enough capacity to enable this customer transition to a more electrified lifestyle. 

This will require that we continue to build and maintain our network to high standards. We will also have to invest in more monitoring and sensing technology to provide us with detailed data about the performance of or assets. This data allows us to make decisions and to create data and business intelligence platforms which will use this rich data asset to help us keep the network strong and reliable. Sharing our focus between fixed assets and sensing and data assets needs a new competence and focus on keeping the data and IT systems resilient to failure and intrusion. 

ESB Networks’ MV overhead network accounts for in excess of 85,000km over a service area of 70,000km2 and provides electricity to almost half of ESB Networks’ 2.3m customers. This network is vulnerable during extremely high wind speed events (gusts of more than 130km/hr), particularly where there are large trees growing within falling distance of the electricity network.

We are looking at a number of measures to increase the resilience of the network in certain targeted areas which are susceptible to timber related outages and are exposed to relatively higher wind conditions than other areas. The concept of ‘Hardening’ the overhead network has been implemented in North America where targeted actions increase the resilience of overhead networks to storm conditions. This project will trial a number of ‘Hardening’ initiatives on an MV outlet and its continuity performance will be tracked.

Sensitive Earth Faults (SEF) are difficult to detect as they have very low fault current values and are as a result relatively more dangerous to the public. During SEF operation, the protection device does not attempt to automatically reclose the circuit breaker to test if the fault conditions are still present. This means that every time the SEF conditions are detected (fault current of<40 but >4Amps for 5 seconds) the customers connected to that circuit will be disconnected until the fault site is visited to ensure that there are no public safety concerns at the fault location. This means that these customers will have relatively poorer network performance than other customers. 

Normal earth fault operation will attempt to clear temporary faults by rapidly opening and closing the circuit breaker or recloser. This project will implement a new protection methodology to improve continuity of supply to customers by reducing the range over which SEF operates while maintaining high levels of fault detection and public safety. 

Faults on the LV overhead network in urban areas generally result in a fuse blowing to isolate the faulted network. Most of the faults on the urban overhead LV network are caused by clashing or falling timber and are transient in nature as the timber clashes and generally falls clear a short time later. However, each time an LV fuse blows the only way of restoring electricity to the customers on that circuit is to dispatch a technician to replace the fuse. 

This results in relatively long outages for these customers, increased fault repair costs and lower customer satisfaction. Trials have been conducted in the Dublin area to improve LV overhead network performance. The trials included several pieces of technology operating in the place of the traditional circuit fuse. Two pieces of unique equipment, the REZAP Modular and BIDOYNG, were effective at reducing the amount of outages and have been selected for further, more extensive use. 

The devices will carry out the following functions:      

  • 5 shot auto-recloser for use on LV feeders. The unit detects a fault but, if the fault is transient, will reclose after a specified time period. This can be specified with a gateway which uploads real-time current and voltage, and transients, to an online platform which can be accessed online. Settings (current to trip ratings etc.) can also be changed by ESB Networks local staff online. The unit sends a text message direct to a phone or phones of our choice if there is any fault activity. 
  •  A single shot auto-recloser with 2 fuses for LV. This is placed on the 2 non faulted phases where the 5 shot auto-recloser is placed on the faulted phase. As faults develop the 3 units together give a complete picture of what is happening – single phase EF, 2 phase EF, Ph – Ph etc.

The 20kV resistance earthed system is proposed to be redeveloped into a hybrid earthing system with both arc suppression and Faulted Phase Earthing (FPE). This is designed so that the fault performance of this network will significantly improve. This is a unique system of fault protection that can safely sustain, instead of tripping for, earth faults. 

ESB Networks has been trialling alternative neutral treatments for the 20kV system since 2009 when the first Arc Suppression Coil (ASC) trial was implemented. This was enhanced in 2013 with the addition of FPE to this solution to develop the hybrid ASC/FPE approach which is proposed for PR4. The demonstration projects since 2013 indicate that the performance of the network under fault conditions will improve by up to 50%. 

This makes the 20kV system less complex for field and control centre staff to operate particularly under fault conditions. This will improve safety and performance for our customers and staff. 

The ESB Networks telecommunications networks consists of multiple platforms over various mediums and is the main means of providing connectivity for system critical services for the electricity network. The range of critical services that will require connectivity on the telecommunications network is predicted to grow significantly, with the bandwidth requirements per service also increasing. For example there is currently 2,400 remotely monitored and controlled devices on the network and it is expected the number of these devices will increase every year as ESB Networks installs more control and sensing devices at MV and LV. 

ESB Networks propose to invest in the installation of a scalable new IP core network to enable the data from these sensing and controllable devices to be captured and securely relayed back to the operational IT systems. This single consolidated new generation network will be a fundamental building block in fulfilling the existing and future communications requirements of the electricity network. This core network will also provide a platform for replacing legacy technologies and systems that are approaching end of life, particularly devices that have GSM and GPRS modems which are likely to fall out of vendor deployment in the coming years. In addition it will act as a key enabler of smart network operations. This is due to the fact that virtually all Smart Grid services use IP for communications and thus require an IP network. 

The existing telecoms infrastructure on ESB Networks’ Telecom Services network is designed to support connectivity to primary substations from 38kV to 400kV. Connectivity beyond the substations is currently supported by public radio networks such as Vodafone GPRS links. Due to the expected growth in equipment and applications on the distribution network seeking communications solutions for transport of data, such public telecommunications network are not sufficient to meet predicted growth in sensors and line equipment on MV feeders and substations. Using such 3rd party networks is a risk due to the proven vulnerability (e.g. cybersecurity, power resilience) and coverage issues (particularly in rural areas) of their networks. This is particularly the case during storm outages when power to the mobile high sites is lost and they cease communicating further delaying the ability of the Control Centre staff to issue commands to devices on the network communicating across 3rd party GPRS networks.

The development of a reliable cyber-secure national area radio access network, independent of the public mobile operators, is needed to meet the demand for machine-to-machine data communication for the control, protection and management of utility assets. This National Radio Access Network project will involve the development of a dedicated wireless network for the reliable transport of data for future smart grid applications. This network will enable the replacement of many of the current systems dependent on public mobile networks, such as fault passage indicators and energy meters, and will provide new systems with their communication needs. The network will also enable large-scale connection to individual devices for asset management purposes. 

Some examples of equipment and applications that will require communications in the future include:

  • Ultra TEV Partial Discharge Monitors        
  • MV Voltage Regulators       
  • Network Re-closers and Soule Switches       
  • SubStation Security Alarms       
  • Voltage and Current Sensing Devices        
  • Circuit Breakers       
  • Fault Passage Indicators        
  • Interface Transformers (20kV to 10kV)       
  • Dynamic Line Rating Sensors

The SUCCESS project is a European consortium made up of industry leaders, high-standing research institutions and the topmost ranked universities. This project aims to design, develop and validate on small scale field trials an adaptable security framework which is able to significantly reduce the risks of cyber threats and attacks when smart meters are deployed. The safe deployment of smart metering is important to ensure that innovative products and tariffs can be offered to customers enabled by these meters.

The SUCCESS project aims to develop three use cases which will incorporate:        

  • Security       
  • Resilience       
  • Survivability        
  • Privacy 

The concepts will drive investigations of threats and vulnerabilities of current and future smart meters. It will also expand out into wider threats to the general power network with smart devices.  The SUCCESS project addresses both electricity networks, and the communications networks and IT capabilities that support them. It considers both of these infrastructures together as they are equally important in the safe and reliable delivery of electricity to our customers. 

The Irish trial addresses the rapid growth of electric vehicle charging, and the resulting opportunities and requirements for grid stabilisation and distribution asset protection, in an environment shielded from cyber-attack.