1KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

ACCURATE MODELING FOR LOSSES REDUCTION USING A REAL-TIME

POWER FLOW AT ENELVEN

I. Roytelman, A. Ilo

SiemensR. CESPEDES

KEMA Consulting

P. Parra, H. Socorro, L. Rodriguez, T. Romero

ENELVEN

2KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

Introduction ENELVEN - utility company in Zulia State, Venezuela

600,000 users, 1,700 MW of power300 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

3KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

DMS Main Components and Interfaces

RTUs

IEDs

Database

Distribution Management System

External Systems

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DistributionAutomation

ERPERP AMFM

/GIS

AMFM

/GIS

CISCIS SCADA

SCADA

4KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

Accurate Distribution Power Flow,

Why? Distribution Power Flow Needs for ENELVEN:

Monitoring the distribution feeder loading and voltages Input for power losses calculationsSupport of Volt-VAr Control with direct benefits

MODELING REQUIREMENTSMultiphase rather than positive sequence onlyDetailed transformer representation rather than lumped

loadsAccuracy adequate for losses calculation (few percent of

total load)

5KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

Accurate Distribution Power Flow, Why?Enelven Specific Distribution System Characteristics: Variety of transformer connections which need to be modeled

accurately.

Connection TypeTotal Number of Installed

Transformer Banks Total Installed

Power

1 Single-phase, phase-ground 35.84 % 22.37 %

2

Single-phase, phase-phase 44.03 % 24.62 %

3

Wye – wye 4.69 % 21.75 %

4

Wye – delta 6.07 % 17.76 %

5

Open wye – open delta 3.05 % 4.50 %

6

Delta – Wye 4.95 % 6.90 %

7

Delta – Delta 0.96 % 1.42 %

8

Open delta – Open delta 0.41 % 0.68 %

  Total 100.00 % 100.00%

Connection Type Transformers Installed in ENELVEN/ENELCO

6KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

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

Phase P 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)

39.21 42.82 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 159.25 157.40 69.92 69.95 174.12 172.24   

7KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

Accurate Distribution Power Flow, Why?Example (cont):

The same for 50/100/50 kVA transformer bank

Loading % wye/wye

Phase P 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)

15.09 16.41 10.91 9.46 18.62 18.94 37.24 37.88

B (bc)

34.81 32.76 19.43 19.04 39.86 37.89 39.86 37.89

C (ca) 16.21 16.40 7.56 9.45 17.89 18.93 35.78 37.86

Total 66.11 65.57 37.90 37.95 76.37 75.76    

8KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

DSPF Input Data

Load ModelingDRTPF

Distribution Network

Applications

GIS DataNetwork elements

geographical location

Distribution SystemOperational Model

(DSOM)

Network Elements Electrical

ParametersLine/transformer

impedances, phases, taps, loads, capacitors

SCADANetwork

description and topology

Field equipment statuses,

measurements

Structure of Distribution

System Operational

Model Interaction

9KEM_Cespedes_A1 Colombia Session 3 – Block 1

Barcelona 12-15 May 2003

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.