1. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 1 ACCURATE MODELING FOR LOSSES REDUCTION USING A REAL-TIME POWER FLOW AT ENELVEN I. Roytelman, A. Ilo Siemens R. CESPEDES KEMA Consulting P. Parra, H. Socorro, L. Rodriguez, T. Romero ENELVEN

2. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 2 Introduction  ENELVEN - utility company in Zulia State, Venezuela  600,000 users, 1,700 MW of power  300 feeders voltages range 6.9 - 34.5 kV  ENELVEN goals - improve the distribution system operation efficiency  GIS based central data repository and Distribution Management System Implementation  Maintain the technical losses at a minimum level  Improve quality of service

3. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 3 DMS Main Components and Interfaces RTUs IEDs Database Distribution Management System External Systems A P I s User Interface Fault Location, Isolation and Service Restoration Fault Location, Isolation and Service Restoration Support Functions Crew Management Outage Management System Switching Order Management Distribution System Power Flow (DSPF) Trouble Call System D S O M (Tools + Methods) Historical Information System Distribution Automation ERP AM FM /GIS AM FM /GIS CIS SCADASCADA SCADASCADA

4. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 4 Accurate Distribution Power Flow, Why?  Distribution Power Flow Needs for ENELVEN:  Monitoring the distribution feeder loading and voltages  Input for power losses calculations  Support of Volt-VAr Control with direct benefits  MODELING REQUIREMENTS  Multiphase rather than positive sequence only  Detailed transformer representation rather than lumped loads  Accuracy adequate for losses calculation (few percent of total load)

5. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 5 Accurate Distribution Power Flow, Why? Enelven Specific Distribution System Characteristics:  Variety of transformer connections which need to be modeled accurately. Connection Type Total Number of Installed Transformer Banks Total Installed Power 1Single-phase, phase-ground35.84 %22.37 % 2 Single-phase, phase-phase44.03 %24.62 % 3 Wye – wye4.69 %21.75 % 4 Wye – delta6.07 %17.76 % 5 Open wye – open delta3.05 %4.50 % 6 Delta – Wye4.95 % 6.90 % 7 Delta – Delta0.96 % 1.42 % 8 Open delta – Open delta0.41 % 0.68 % Total100.00 % Connection Type Transformers Installed in ENELVEN/ENELCO

6. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 6 Accurate Distribution Power Flow, Why? Example: the same transformer bank ( wye/delta) and (wye/wye) with similar load produces different primary side phase loadings and power losses. Primary side power flow for 100/167.5/100 kVA transformer Bank Connected in wye/delta and wye/wye with the same secondary side load PhaseP kW wye/delta P kW wye/wye Q kVAr wye/delta Q kVAr wye/wye S kVA wye/delta S kVA wye/wye Loading % wye/delta Loading % wye/wye A (ab) 39.2142.82 18.88 19.01 43.52 46.85 43.52 46.85 B (bc) 73.92 71.7 35.21 31.91 81.87 78.48 48.87 46.86 C (ca) 46.12 42.88 15.73 19.03 48.73 46.91 48.73 46.91 Total 159.25157.40 69.92 69.95 174.12172.24

7. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 7 Accurate Distribution Power Flow, Why? Example (cont) : The same for 50/100/50 kVA transformer bank Loading % wye/wye PhaseP kW wye/delta P kW wye/wye Q kVAr wye/delta Q kVAr wye/wye S kVA wye/delta S kVA wye/wye Loading % wye/delta A (ab) 15.0916.41 10.91 9.46 18.62 18.94 37.24 37.88 B (bc) 34.8132.7619.4319.0439.8637.8939.8637.89 C (ca) 16.21 16.40 7.56 9.45 17.89 18.93 35.78 37.86 Total 66.1165.57 37.90 37.95 76.3775.76

8. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 8 DSPF Input Data Load Modeling DRTPF Distribution Network Applications GIS Data Network elements geographical location Distribution System Operational Model (DSOM) Network Elements Electrical Parameters Line/transformer impedances, phases, taps, loads, capacitors SCADA Network description and topology Field equipment statuses, measurements Structure of Distribution System Operational Model Interaction

9. KEM_Cespedes_A1 Colombia Session 3 – Block 1 Barcelona 12-15 May 2003 9 Conclusions  An accurate three-phase unbalanced power flow is required by ENELVEN to improve operation efficiency.  ENELVEN different distribution transformer connections combined with an strategic requirement of correct calculating of the power loss (a significant percent of the total load), makes the requirement for accurate DSPF.  Results obtained with the DRTPF are promising both in terms of performance and usefulness. DRTPF will become certainly of great interest for utilities with similar problems.