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Atif Saleri, Market Development Manager for ABB Ability explains new peak time penalty charges for electricity and how the latest generation of smart circuit breakers can help avoid them.


he UK’s electrical utilities are preparing to apply new peak charges under new legislation being introduced on 1st April by Ofgem, the energy regulator. The new DCP161 regulation will allow grid operators to charge up to three times the standard rate for energy that exceeds a customer’s agreed peak consumption. Ofgem took the decision to introduce DCP161 after recognising that Distribution Network Operators (DNOs) have been incurring significant costs to manage ever-higher levels of peak consumption. Although utility customers pay a fee for a new connection, this only covers consumption up to an agreed level. Utilities reported a trend for some customers to regularly draw more than their agreed maximum and until this year, excess consumption has always been charged at the standard rate. Since this arrangement meant that utilities had to invest in network upgrades, Ofgem took the view that it was an equivalent to a discount – and therefore applying a penalty rate would encourage more careful energy consumption. The new penalty fee will vary between regions and voltage levels and will be applied over half-hour average consumption periods. This presents building operators with the challenge of controlling a building’s loads. For example, on a hot summer’s day, HVAC (Heating, Ventilation and Air Conditioning) systems may power up simultaneously, creating a peak in consumption and potentially incurring a penalty.

NEW GENERATION OF CIRCUIT BREAKERS For those who find that they regularly draw more than their agreed limit, there are two choices. They can either negotiate a new peak energy level with their DNO or install a fail-


safe system to cap consumption while maintaining uninterrupted services for the building’s occupants. The conventional way to limit electricity consumption to a specified maximum is to install load control devices to individually manage each load. These can be extremely complex and costly to engineer and maintain and require accurate metering, PLCs and switchgear controllers. However, the latest generation of low voltage circuit breakers has the capability to do more than its traditional role of controlling the flow of power in a facility. Modern circuit breakers benefit from in-built protection, control and automation technology. They were developed in anticipation of the trend for facility managers to exert more control over their energy consumption. In addition, they have applications on board ships and in other installations that have an absolute limit in available power and where exceeding peak power could lead to a blackout.

INTELLIGENT DECISION MAKING The key to keeping consumption below a peak is the ability to monitor consumption and switch off low priority loads automatically, before switching them back on again (also automatically) so that building occupants are not aware of any changes. With this type of intelligent decision making, integrated metering and control built into a single unit, such circuit breakers can completely replace the need for a load control installation. The new capabilities have given circuit breakers the ability to perform as a self-contained power manager. Inside the circuit breaker, accurate metering continuously measures the total power flow through the breaker and calculates the average consumption. In the case of DCP 161,


the building operator can choose to calculate consumption over half-hour periods and set a cap that is equal to the maximum in their contract. The breaker’s algorithm then runs a regular decision-making process. As well as constantly monitoring consumption, it also forecasts average consumption over the half-hour periods – and chooses either to maintain the existing loads, decrease or increase them. The final step is deciding which loads to switch and this is based on a set of rules that prioritise loads based on importance, “respect time” (the minimum time that a load must remain connected or powered down to avoid damage) and whether any loads are available again once their respect time is past.

SIGNIFICANT SAVINGS One manufacturing facility in Bergamo, Italy is using smart circuit breakers to control HVAC loads and save up to 11,000 Euros per year. The plant’s HVAC loads have a combined capacity of 400 kW and are controlled through four smart circuit breakers that are fed from two transformer units and control up to 15 individual loads or 15 groups of loads. Three of the breakers are operated as general low-voltage circuit breakers – but the fourth has been fitted with power management software. This is embedded into the breaker’s electronic trip unit – and because this is already used for overcurrent protection, no complex control system or dedicated software was required. A dedicated Ethernet communication cable connects the four breakers together to enable remote control. The breaker equipped with power management software monitors the total consumption through all four breakers, which have in-built metering. It then decides whether to disconnect or reconnect loads – as well as which loads.

Energy Manager March 2018  
Energy Manager March 2018