1Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Technical Assessment for the Installation of Dispersed

Generation in Distribution Networks

N. Kagan, C.C.B. Oliveira, J.C.B. Silva

Enerq/University of São Paulo

C. R. Benedik, A. Conceição

Elektro – Eletricidade e Serviços SA

2Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Objectives

• Assessing the impact of new DG units in Distribution Systems

• Power flow study

• Short circuit study

• Consideration of subtransmission and primary distribution networks

3Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

DG units in the Distribution System

4Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Power Flow Study• Subtransmission networks

– Newton Raphson Method

• Medium voltage networks– Radial/three-phase load flow method

• Integration of above methods

5Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Subtransmission Networks

- Swing bus (or slack bus): voltage magnitude and angle are known (multiple supply busses connected the transmission grid).

- PV or generation bus: active power and voltage magnitude are known (representing DG units).

- PQ or load bus: active and reactive power are known.

6Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Newton Raphson Formulation

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)(cos

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43

21

Reactive power are then obtained in DG units to be used as an input to MV network load flow

7Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Medium Voltage Networks

• Radial networks (usually)

P+jQ

8Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Medium Voltage Networks

• Three-phase modelling

• Load flow is based on ordering network busses and branches

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Network branch

9Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Short Circuit Calculations

External network

Studied network

Supply nodes

Studied network

Z1

Z2

Z12

DG unit

Complete network Equivalent network

10Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Short Circuit Calculations

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11Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Computational System

• Integrated (subtransmission + primary distribution network) analysis

• Interface with the company’s corporative data base

• Friendly user interface

12Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Subtransmission network

13Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Primary Distribution Network

Network reduction

14Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Load flow study

15Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Short circuit study

16Nelson Kagan BR Session 4 – Block 3 – Planning – Paper #66

Barcelona 12-15 May 2003

Conclusions

• computational tool to evaluate technical aspects related to the installation of DG units in electric power distribution systems

• DG units in the reduced MV network for conventional load flow and short circuit methods

• DG injected power flows are determined for different load levels and the MV network is analysed in detail by a specifically designed three-phase load flow algorithm