11

Standardization approaches in various countriesGrid Interconnection

1. IEEE 1547, Standard for interconnecting Distributed Resources with Electric Power Systems

2. Switzerland: STI 219.0201d, Parallelbetrieb von EEA mit dem Niederspannungsnetz

3. Austria: Paralllelbetrieb von Erzeugungsanlagen mit Verteilernetzen

4. Sri Lanka: CEB Guide for Grid Interconnection of Embedded Generators, December 2000

2

Standardization approaches in various countriesGrid Interconnection

Other references:

UK: Electricity Standard G83/1, for embedded generators up to 16Amps per phase

UK: Electricity Standard G59/1/NI: for embedded generators less than 5 MW and 20 kV

Canada: Various work ongoing

Ireland: Grid Code Connection Conditions (CC), CER/0104/01, 2001

Australia: AS 4509.1-1999, .2-2002, .3-1999, Stand-alone power systems

3

IEEE standardGrid Interconnection

27 pages The actual technical part

covers only 10 pages

4

IEEE standardGrid Interconnection

Terminology: Distributed Resource, Point of Common Coupling

Micro-grid aspect is implicitely covered (Area EPS) but not suitable for Nepali needs: The DR shall not energize the Area EPS when the Area EPS is de-energized.

Specified for 60 Hz

25

SwitzerlandGrid Interconnection

20 pages

Local grid is covered but only as local 400V loads

Typical connection diagrams are useful for showing area of application. Applicable to 400V only.

6

Swiss rules

Grid Interconnection

1. Synchronous generator without isolated operation

(400 V)

7

Swiss rules

Grid Interconnection

2. Asynchronous generator (without isolated operation)

400V connection

8

Swiss rules

Grid Interconnection

3. Synchronous generator with isolated operation

400V

39

Swiss rules: Protection and tolerances

Grid Interconnection

Setting of voltage relay: UN +/- 10%Setting of frequency relay: fN +/- 1%

Frequency relay is optional if a vector shift relay is provided.

Synchronizing conditions: At least UN +/- 10% fN +/- 0.5 Hz Dj +/- 10

Cos Phi shall be between 0.9 capacitive and 0.8 inductive (exactvalue may be fixed by the utility)

Remote command signals must not be disturbed (provide filters)

Utility staff must permanently have access to an isolator switch

10

Austrian rules

Grid Interconnection

31 pages

Slightly more global approach than Swiss guideline

Defines system services:- Power factor correction- Voltage stabilization- Frequency control

No detailed rules for protection; these have to be fixed individually

11

How the standards compareGrid Interconnection

Not relevant for Nepali micro-hydro contextDesigned for use by approx. 15 power retail companiesOften identical sell&buy rates

Basically focussed on inverter-based solar PVSmall systems = 10 kW

Australia

All kinds of plants but LV only

Switzerland

Focusses on MW-sizeIsolated start-up is prohibited

413

The Nepali ModelGrid Interconnection

The Nepali model is based on a long-term vision: The Dynamic Power Grid

14

The Nepali ModelGrid Interconnection

The Dynamic Power Grid: Flexible topology and free flow of energy. An information network is used to manage the power network. Substations are generally equipped with synchrocheck reclosers

Island

Island

Reduced network load

15

The Nepali ModelGrid Interconnection

Islands can participate in the grid or not; innovative technicalsolutions are to be developed.

- New versatile distribution system designs for instance, overlapping national grid with island grid for more flexibility

- Communication technology or other intelligent ways to exchange grid information

16

The Nepali ModelGrid Interconnection

Islands can participate in the grid or not; innovative technicalsolutions are to be developed.

- New versatile distribution system designs for instance, overlapping national grid with island grid for more flexibility

- Communication technology or other intelligent ways to exchange grid information