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Projects: Projects for Investigator
Reference Number NIA_SSEPD_0029
Title 11kV power electronics providing reactive compensation for voltage control
Status Completed
Energy Categories Other Power and Storage Technologies(Electricity transmission and distribution) 100%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 100%
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
Scottish Hydro Electric Power Distribution plc (SHEPD)
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 June 2016
End Date 01 December 2019
Duration 42 months
Total Grant Value £732,000
Industrial Sectors Power
Region Scotland
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , Scottish Hydro Electric Power Distribution plc (SHEPD) (99.999%)
  Other Investigator Project Contact , Southern Electric Power Distribution plc (SEPD) (0.001%)
Web Site http://www.smarternetworks.org/project/NIA_SSEPD_0029
Objectives 1. Determine the operational requirements of the device and the standards that it should be constructed to. 2. Confirm that the device meets the construction standards. 3. Establish a safe connection methodology for both overhead line, and ground mounted variants of the device. 4. Determine, by testing, that the device meets the operational specifications. 5. Install two pole mounted and one ground mounted device on the distribution network. 6. Monitor the effects on the network by comparing voltage profiles from before and after the installation of the devices. 7. Confirm that the device is reliable in service, and across a range of weather conditions, and determine the cost of maintenance. 8. Determine the suitability of the method for business as usual deployment This project will be successful if we are able to determine the ability of the devices to maintain the voltage within statutory limits and to reduce apparent step changes in voltage.
Abstract Rural areas of GB are supplied by networks which often experience large voltage changes. These are a consequence of changing customer loads or generation output in the network. When these changes take place in a network with a high source impedance they result in noticeable changes in voltage. The voltage can in some cases go outside of the statutory limits. At low voltage these are 230v plus 10% to minus 6% or from 253 volts down to 216. 2 volts. There are several ways to tackle this problem as follows. 1. Reduce the source impedance by installing larger transformers, cables and overhead lines. 2. Install voltage regulators to increase or decrease the voltage. 3. Install reactive power compensation equipment to increase or decrease the reactive power flowing in a network. Reactive power can have a significant effect on the voltage. Typically generating reactive power at the remote end of a circuit will boost voltage and absorbing reactive power will reduce voltage. If there is only one requirement then capacitors can be used to boost voltage. Shunt reactors can be used to reduce voltage. A range of manufacturers have produced power electronic reactive power compensation units, these can be used to both create reactive power like a capacitor, or to absorb reactive power like a shunt reactor. The power electronics in these devices typically operate at 400 to 480 volts and at the smallest end of the range are directly connected to LV networks. Where connection is required to high voltage networks this is carried out using suitable interposing transformers. Typically the power electronics require cooling, which is usually carried out by blowing air through the unit with a fan. For larger units the air may be cooled using an air conditioning system. Power electronic reactive power compensation units have several advantages over fixed capacitors and shunt reactors. ; Firstly they can be fitted with very fast acting control systems which can correct voltages so quickly that customers do not notice that they have operated. ; Secondly they can be controlled to provide small steps in output to closely match the required reactive power to that required to keep a constant voltage on the network. ; Thirdly they can continue to provide reactive voltage support during both voltage and frequency deviations from normal. The currently available power electronic reactive power compensation units have the following disadvantages; Firstly, they need an interposing transformer to allow connection an HV network; Secondly, the cooling system is noisy, and can be unreliable; Thirdly, overall cost of ownership tends to be high. A technical method is proposed. This involves the deployment of a newly developed power electronic reactive power compensation unit, of a novel design which operates with a direct connection at 11kV. This may eliminate most of the issues noted above with current products; The device uses power electronics connected directly at 11kV hence eliminating the expense of an interposing transformer between low voltage power electronics and the high voltage network. By removing the transformer the overall weight is reduced considerably. A device with a rating of +-1MVAr can be mounted in three tanks. These along with a control box and external HV switches can be mounted on a wood pole structure comprising two poles. This type of arrangement is often used for 100kVA and 200kVA transformers. ; In addition, cooling isdone passively using an oil based cooling liquid. This eliminates the need for fans, air filters etc which both reduces noise and eliminates lots of components which are prone to failure. The cooling liquid is based on a vegetable oil. In the unlikely event of a leak the liquid is biodegradable. The liquid also has a relatively high flash point reducing the risk of fire should the tank be ruptured. The device will be tested at the Power Networks Demonstration Centre (PNDC) in Cumbernauld. This will ensure that it can operate over the full voltage, and frequency envelope it is designed for. This testing is important as these extreme events are unlikely to occur very often, if at all, on our normal network. However the capability of the electronic reactive compensation unit to operate under these unusual conditions to maintain voltage is very important. The equipment supplier has developed the device and will own all the associated Intellectual Property. Scottish and Southern Energy plc will develop installation methods and the communications required to allow the device to be integrated into our overall voltage control system. All development carried out by SSEPD will be shared with other DNOsNote : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications (none)
Final Report (none)
Added to Database 20/03/18