The National Commission for Energy State Regulation of Ukraine Energy The Public Utilities Commission of Ohio Distribution System Losses

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1 The National Commission for Energy State Regulation of Ukraine Energy The Public Utilities Commission of Ohio Distribution System Losses Michael D Simms PE 11/8/13

2 US Utility Industry Loss Data Total losses Total distribution losses, not including the substation transformer averaged 3.2% of total consumption. 75% of circuits had losses exceeding 2.16%, and 25% of circuits had losses exceeding3.94%. Line losses Line losses averaged just under 1.5% of total consumption. Circuit length is a reasonably good predictor of percentage line losses. Transformer no-load losses Transformer load losses averaged about 1.4% of total consumption. These losses were the most consistent across circuits, depending mainly on transformer age and transformer utilization (connected kva versus load). Secondary losses For the most part, these tend to be low. Demand At peak load, losses average 4.2% of consumption. 75% of circuits had peak losses exceeding 2.52%, and 25% of circuits had losses exceeding 5.40%. One circuit it had peak losses of 13.6%. Losses at peak are predominantly line losses. 2

3 US Utility Industry Loss Data Voltage optimization for energy reduction Voltage reduction to reduce energy successfully reduces energy consumption on almost all circuits. The median reduction in energy was 2% with upper and lower quartiles of 1.3 and 2.8%. Reactive power improvements Most circuits did not see significant savings with improved reactive power support. A few circuits have opportunity for significant savings. Phase balancing As with var improvements, options for phase balancing tend to be circuit specific. Simplified modeling Traditionally, utilities evaluate losses based on a peak case and use an estimated loss factor to evaluate annual performance. Comparing our detailed simulations to the simplified approach shows that the simplified approach is relatively accurate with the right loss-factor estimation equation. The outliers that don t conform to this tend to be the lossiest circuits. 3

4 Loss Improvement Phase balancing rearranging loads on each phase of the circuit to reduce residual flows Reactive power optimization additional capacitor banks or altered switching scheme Voltage optimization also known as conservation voltage reduction intentional lowering of distribution circuit voltage within the allowed ANSI range Selected reconductoring replacing selected conductor sections with larger, lower-resistance conductors High-efficiency line transformers replacement of lower-efficiency line transformers with higher-efficiency transformers 4

5 Loss Analysis Practices Peak Model typically used Power factor is estimated Capacitance sized for peak load with some margin for capacitance not being available Planning, engineering i and standards d guidelines utilized to minimize i i losses 5

6 Distribution Management System (DMS) Model Enterprise Geospatial Information System (EGIS) Based Model Foundation for DMS and load flow Field verified for accuracy 6

7 Distribution Management System (DMS) /Integrated Volt/Var Control (IVVC) Overview Voltage control actions based circuit load flow modeling with near real time feeder load input Capacitor switching and LTC/regulator tap position based on combination that will produce the lowest load as measured at the substation Calculates customer load + losses System Optimization Engine including IVVC and Loss reduction 7

8 Integrated Volt/Var Control (IVVC) Problem Formulations Minimize Loss The Minimize Loss problem formulation is used to reduce the total losses in the distribution system. These losses include line losses, reactor losses, and transformer losses, including station transformers, auto-transformers, regulators, and distribution transformers. Minimize Demand The Minimize Demand problem formulation minimizes the total demand (loads plus loss) in the distribution system. IVVC most likely attempts to reduce the load voltages, lowering the overall demand (the load-to-voltage dependency data has a great impact). Based on the available controls and the existing voltage profile, it may not always be possible to reduce the total demand. d 8

9 Integrated Volt/Var Control (IVVC) Strategy Near real time load flow based calculations Power Factor Goal-unity at the transmission side of power transformer Capacitance managed by IVVC control Loss reduction managed by IVVC control Ultimate goal is to reduce load measured at substation Substation ti load = customer load + losses 9

10 Distribution Management System (DMS) Loss Summary Data Substation Loss Summary Name Total Loss kw Total Loss kvar Power Power Station Station Transformer Transforme Regulator Regulator Loss kw r Loss kvar Loss kw Loss kvar Station Series Reactor Loss kw Station Series Reactor Loss kvar Feeder Loss kw Feeder Loss kvar ABC

11 Distribution Management System (DMS) Loss Summary Data Transformer Loss Summary Name ID Type Source Phasing Rating Real Copper Loss Reactive Copper Loss Reactive Core Real Core Loss Loss BK1 1 Regulator ABC MVA kw kvar kw kvar Regulated VR_1 A 2 Regulator AN kva 1.27 kw 3.18 kvar 0.54 kw kvar VR_1 B 3 Regulator BN Regulated kva 1.21 kw 3.02 kvar 0.54 kw kvar Regulated VR_1 C 4 Regulator CN kva 1.24 kw 3.10 kvar 0.54 kw kvar 11

12 Distribution Management System (DMS) Loss Summary Data Feeder Loss Summary Name TotalFeeder Loss TotalFeeder Loss kw kvar Total Distribution Transformer Loss kw Total Distribution Transformer Loss Total Regulator kvar Loss kw Total Regulator Loss kvar

13 Green Circuits: Distribution Efficiency Case Studies. EPRI, Palo Alto, CA:

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