Smart Grid Technologies Feasibility Study : Increasing Decentralized Generation Power Injection Using Global Active Network Management
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C I R E D 21st International Conference on Electricity Distribution Frankfurt, 6-9 June 2011 Paper 0316 SMART GRID TECHNOLOGIES FEASIBILITY STUDY : INCREASING DECENTRALIZED GENERATION POWER INJECTION USING GLOBAL ACTIVE NETWORK MANAGEMENT Olgan DURIEUX Vanessa DE WILDE Jean-Jacques LAMBIN ORES - Belgium Elia - Belgium Elia - Belgium [email protected] [email protected] [email protected] Stéphane OTJACQUES Michel LEFORT Elia - Belgium ORES - Belgium [email protected] [email protected] exchange for managing those flows and safeguarding the ABSTRACT system security. The current paper presents how smart grids technologies like Active Network Management (ANM) can be used as A high potential for distributed generation deployment an alternative solution to network infrastructure (mainly wind farms) has been detected in Belgian areas reinforcement in order to increase Distributed where connecting these new power injections could Generation (DG) connection/injection possibilities. threaten the grid security as the grid is subject to potential The paper describes an ANM feasibility study that is thermal overload in worst case situation. currently led by both the TSO Elia and the DSO ORES in One of these areas is situated in the eastern part of the east area of Belgium on a whole network facing Belgium and the electrical network is the so-called “east potential congestion problems. The study is performed by loop”. Both transport (70 kV) and MV distribution (15 Elia and ORES with the competences and know-how of kV) networks are facing potential congestion problems. Smarter Grid Solutions Ltd. (UK, Glasgow). Therefore, ORES and Elia decided not to wait for the Principles of access to the network and new rules of infrastructure reinforcement, which could lead to long connection are presented. delays, but would like to preventively address the The global approach needed to find an economical and problem and enable the connection of additional technical optimal solution on a coordinated way with the generation units using technologies like real time active TSO and the DSO is underlined. network management solutions. So they have launched a Besides the ANM feasibility study, the paper also Smart Grid project on this part of the network aiming at presents how Elia and ORES are currently testing flexible studying the feasibility of a solution which could be access methods in a concrete and limited pilot project. replicated on other congested networks. INTRODUCTION The Belgian energy landscape has got one TSO, which is unique and federal, and several DSO’s, which are regional. Elia s.a. (www.elia.be) is the single TSO (owner and operator of the electricity transmission network) in Belgium. ORES s.c.r.l. (www.ores.net) is the distribution network operator (distribution of 36 TWh in electricity per year and 61 TWh in gas per year) for the great majority of distribution network owners in the Walloon area (south of Belgium). Due to the increasing amount of distributed generation injecting active power at distribution level, the power Figure 1 : Belgium, map of Wallonia, location of the flow through the HV/MV transformers in the substations “east loop” network. connecting the transmission (Elia) and distribution (ORES) networks became clearly bidirectional, requiring ANM takes control actions to automatically maintain closer TSO/DSO collaboration and extended data networks within their normal operating parameters. What is ANM could be explained in many ways but a good Paper No 0316 1/6 C I R E D 21st International Conference on Electricity Distribution Frankfurt, 6-9 June 2011 Paper 0316 reference definition is given in the report issued by the eastern area of Belgium. A simplified topology of this CIGRE C6.11Working Group relative to active network area is shown on figure 3. distribution networks [1]. Heid de Goreux 70 kV Romsée 70 kV T2 T1 S 0 M 6 kV 6 The growing penetration of distributed generation makes A 3 . 2 0 8 T8 7 1 HY 70.360 energy flows variable in value and direction, which is a Soiron Pepinster 9 15.6 kV 4 Romsée 3 . S 0 9 2 220 kV M 7 5 complete change and a big challenge to face for network 6 A 3 3 . 2 0 0 8 7 7 operators. As it is not economically possible to replace 1 70.351 Beverce Bomal Comblain existing network infrastructure by a new “fit-&-forget” T1 T2 T3 70.362 6 kV 0 Bronrome 5 3 . one and as energy flows can change at any time, existing 0 15.8 kV 7 HY 1 3 3 2 . 6 0 HY 3 networks have now to be managed in an active way 7 . Rimière Coo 0 70 kV 7 T2B 70.332 within compressed delays (as close as possible to real Stephanshof T3 T2A time). This is only possible with the deployment of robust Trois-Ponts 15.7 kV Rimière T1 T2 0 Bütgenbach telecommunications networks and ICT systems (data 3 220 kV 3 . 7 0 4 7 . 5 management systems, power flow simulators, state 1 Amel 5 2 3 . estimators, SCADA, etc.) as a critical basis of the power 0 Legend T1 T2 7 HYHydroelectric network. Switch (disconnector) Circuit breaker Brume 15.7 kV Overloaded circuit 380 kV 9 2 3 . 0 7 Up to now, criteria for new generators connection onto T1 T4 T3 the network were based on installed power, i.e. a Brume St Vith 220 kV producer is accepted if it is possible to permanently inject T1 T2 15.6 kV its maximum power on the network in N-1 situation. 8 2 3 3 6 4 . 3 0 0 . 5 7 0 . 7 0 2 Typical on shore wind farms generation can be below 2 50% of the rated maximum power for 85 % of the 220.504 Cierreux operation time. Villeroux As an example, figure 2 shows the monotone curve of a 220 kV T3 T2 T1 15.8 kV 7 TJ 2 CHP 3 wind farm injected power versus percentage of time. 0 15.8 kV T11 7 T1 East Loop Houffalize 70 kV 8.4 MVA P max Figure 3 : east loop network simplified topology. All 70 kV equipments including 70/15 kV transformers 0,5 Pmax are managed by Elia; the MV network is managed by ORES. The 70 kV loop is directly connected to 380 kV and 220 kV networks through two substations of the east loop Power % time (Brume and Houffalize) and indirectly through two 15 % overhead lines connected to substations located outside Figure 2 : example of wind farm monotone curve. the area (Romsée and Rimière). Most of the HV/MV substations are operated with one transformer (a second This fact leads us to conclude that the non used reserved one is ready for backup situation). Some generators are capacity could be dynamically allocated for new directly connected to the 70 kV network but most of them incoming generators if network and production systems are connected to the distribution network. Most of the are both managed in an active way. This new concept of loads are connected to the MV network. capacity allocation requires dynamic injection rules to be The east loop was initially designed for a rural area. A defined and applied. large amount of wind generators and other DGs connected on this network (solar panels generation on ACTIVE NETWORK MANAGEMENT distribution low voltage networks are significant) leads to power flow “inversion” (i.e. from distribution to transmission) and 70 kV lines overload. Analysis Current congestions Topology of the network There are currently no thermal overload on the east loop The so-called “east loop network” is a set of 70 kV network and all generators have a firm connection i.e. transmission lines supplying substations located in the they can produce their contracted maximum power in N-1 Paper No 0316 2/6 C I R E D 21st International Conference on Electricity Distribution Frankfurt, 6-9 June 2011 Paper 0316 situation. Load flows studies however show that thermal and maximizing power injection at substation level) on overload problems due to power flows on the the 70 kV loop. A shared percentage method proportional transmission circuits are expected with existing to the output power at the time of the constraint has been generators and future (contracted) ones in case of low chosen to curtail generators in the substations consumption. contributing to the constraint as issued by the power flow calculation. Curtailment needs If non technical aspects (which are not developed in the current paper) are taken into account, this method is The east loop is the focus of interest for many potential maybe not a final and replicable choice but it appears to producers. Reinforcements of potentially overloaded technically address the constraint problem and is circuits offer a solution for contracted generators but equitable for generators. don’t allow to host further more firm DGs on the network. Substations have 2 or 3 output circuits through Curtailment simulations which extra power can be flown away. Reinforcements will modify constraint locations and move thermal The curtailment assessment would give an estimation of overload problems to others circuits under different yearly energy production (MWh) and constraint volumes outage conditions. i.e. it estimates how much energy can be produced and Overloads level depends on production and consumption how much production must be curtailed for each time conditions. Static line rating is currently used for the step (1/4 hour), in each substation. definition of line overload limit but Elia is performing A minimum viable generation capacity depending on the some tests with Ampacimon© monitoring systems [2] [3] type of the generator (wind or CHP) is defined with an for dynamic line rating, which would lead to a real time utilization factor.