Market view: Making distribution smarter

The NTVV project is exploring ways of embedded measurement and telemetry in electricity distribution networks to make them smart enough to handle embedded generation.

The traditional model of low-voltage (LV) distribution has revolved around new connections, maintenance and fault management. Networks are maintained to a high standard but there is little need for centralised operational management. It is also accepted that LV networks draw power from upstream systems and there is little embedded generation.

This practicality and simplicity has allowed DNOs to construct networks that can be operated with no remote telemetry or local measurements, yet still ensure reliability. Because there is little measurement or telemetry, fault response tends to follow time-tested methods. Responders have to piece together clues from different sites along the LV feeder to diagnose the fault location.

However, network monitoring and automation on the LV network has been constantly improving as DNOs strive to enable customers to use low-carbon technologies with no loss of quality of supply.

To improve customer service, DNOs are considering technologies such as smart circuit breakers, smart links and substation monitoring, both on the low-voltage network and in customer premises. Smart meters also represent a great opportunity for DNOs to gather real-time indications of network failure or unacceptable system voltages.

This increase in data means the DNO will be able to respond to faults and restore supply faster, possibly before the customer notices any interruption. These changes prepare the network for the inevitable increasing take-up of low-carbon technologies and also help make new connections simpler.

Opportunities and challenges                                                                                

The sheer volume of LV networks means the adoption of new technology can be expensive and requires co-ordination across a range of stakeholders.

Delivery of smart LV networks needs to consider the most important stakeholder at the centre of all of this activity, the customer. Their participation in the operation of the network may become much more interactive. Electricity consumers have traditionally been passive, with most interacting with DNOs only to report network failures. In the future, they may control demand or generation for both their benefit and that of the network. Time-of-use tariffs may give consumers an incentive to change their consumption patterns and behave in a manner that could support network operation.

To make smart LV networks an attractive proposition for all stakeholders, the technology needs to be affordable and easily deployable. This could be a barrier to future success, although increased adoption will likely bring equipment costs down and provide learnings for larger installations.

NTVV                                                                                                                       

The NTVV project has made use of a distribution management system designed to address many of these challenges and demonstrate how extensive monitoring and control of the LV network can be implemented.

GE Grid Solutions, in conjunction with Scottish and Southern Electricity Networks, has integrated a system to provide an accurate and up-to-date network management and visualisation platform. This informs the decision-making and network planning. This will allow the DNO to control smart technologies connected to the network and also to add tools that can perform other operations, such as managing network faults.

NTVV has created a set of procedures that will help the transition from a trial of smart LV networks to business-as-usual. Under NTVV, Scottish and Southern Electricity Networks has also developed active distribution device management (ADDM) to automatically dispatch smart technologies such as energy storage management units (ESMU) and demand-side response (DSR). This means better use and improved quality of supply with potentially fewer interruptions for customers.

One of the most valuable lessons learnt from NTVV has been where and how to best deploy smart technologies such as ESMUs, ADDM and DSR on the network. One of the greatest benefits that will flow from smart networks is the ability to cope with changing demand patterns without always resorting to reinforcement. Effective control of smart technologies such as ESMU and DSR through a demand management system will become increasingly important in ensuring the DNO operates within its limits.

Things need to change                                                                                           

Currently, the cost of smart technologies is high. Costs need to fall before DNOs are able to widely implement the types of technologies used in NTVV. The LV network is large and widely distributed, which means large-scale implementation will take both time and resources.

The greatest change will be the way in which the DNO sees itself. Traditionally, a DNO has largely been an owner and maintainer of network assets. DNOs also install and supply the physical network needed to move electricity from the transmission level to the point of consumption. This is a largely passive approach to network management, where there is little control of energy flows. However, it will be increasingly necessary for DNOs to take a more active role in maintaining network power flows in real time.

This seems likely to lead to the differentiation between the system and network operation functions. In the future, DNOs may become distribution system operators (DSOs). While there is no clear model for what obligations and incentives will drive a DSO, it is clear from the NTVV learning that smarter, active LV networks can contribute to the DSO of the future being able to have increasing levels of control over the power flows through their network. Such control will undoubtedly lead to opportunities for greater investment efficiency and could open up new opportunities where LV network flexibility provides auxiliary services to the transmission system operator. The resulting cost synergies will ultimately benefit the end customer.

This article is the third of five looking at how Scottish and Southern Electricity Networks and the NTVV project have been exploring better ways of managing distribution networks.