Demand Response and Wind Power Ramp Limitation for Reducing

Frequency Excursions in Power Systems with High Wind Penetration

J. E. Villena Lapaz1, A. Vigueras Rodríguez1, E. Gómez Lázaro1, A. Molina García2, I. Muñoz Benavente2

1Renewable Energy Research Institute (IER), University of Castilla-La Mancha2Department of Electrical Engineering, Universidad Politécnica de Cartagena

EWEA Conference. Brussels, 15th of March, 2010

Index Introduction

Power System model

Simulation and results

Conclusions

Index Introduction

Power System model

Simulation and results

Conclusions

Index Introduction

Power System model

Simulation and results

Conclusions

Index Introduction

Power System model

Simulation and Results

Conclusions

Index Introduction

Power System model

Simulation and results

Conclusions

Motivation Current and future rising of wind power

Stochastic nature of the wind:- Active power fluctuations of the wind farms

- Balance between produced and consumed power

- Grid frequency excursions High penetration of cooling and heating loads,

which cycle on and off

Grid Code requirements

Aim of the work Studying the contribution of the demand side to

the primary frequency control

Assessing the effect of positive ramp limitation

(PRL) applied to the active power generated

form wind, on both the frequency excursions and

the Demand Response

Index Introduction

Power System model

Simulation and results

Conclusions

Power System Model Conventional generation

Wind farm generation

Load

Power System model

Power System Model Conventional generation

Thermal Plant

Power System Model Conventional generation

Hydraulic Plant

Power System Model Wind power generation (500 MW

simulated offshore wind farm)

Power System Model Wind power generation (with PRL)

Power System Model Load- Constant demand (1 GW)- Controllable Load (0.1 pu)

Power System Model Power System- ΔPm , generated power variation

- ΔPD , demanded power variation

- Δf , frequency error

- Df , damping factor

- ωk , kinetic energy stored in the rotating masses

Power System Model

Thermal Plant

Wind Farm

Hydro Plant

Power System

Load+

+

-

+

ΔPT

ΔPH

ΔPWF

ΔPm-ΔPD

Δf

ΔPD

+

+

-

-

AGC

AGC

Gain

Gain

Index Introduction

Power System model

Simulation and results

Conclusions

Simulation and Results 2-hour simulation Wind farm power between 15 % and 40 %

during the simulation Two conventional plants involved in

frequency control 1 GW constant load 10 % controllable load (only negative

frequency excursions) PRL (1 % energy losses)

Simulation and Results Scenario 1: Uncontrolled customer-side

power demand (constant Load) Scenario 2: Demand Response facing

frequency excursions (variable Load) Scenario 3: Demand Response & PRL

(1 % energy loss)

Simulation and ResultsScenario 1 (uncontrollable

load)

Simulation and ResultsScenario 2 (controllable

load)

Simulation and ResultsScenario 2 (controllable

load) Example of Demand Response

Simulation and ResultsScenarios 1 & 2

Example of comparison of frequency excursions

Simulation and ResultsScenarios 1 & 2

Comparison of frequency excursions (reduction of 18.15 %)

Simulation and ResultsScenarios 1 & 2

Example of comparison of conventional generators behaviour

Simulation and ResultsScenario 3 (PRL)

Simulation and ResultsScenarios 2 & 3

Simulation and ResultsScenarios 2 & 3

Example of comparison of Demand Response and frequency excursions

Index Introduction

Power System model

Simulation and Results

Conclusions

Conclusions Demand-side must be considered as a

potencial contributor to the primary frequency control.

Simulations have shown a significant reduction of grid frequency excursions for a reasonable amount of controllable loads.

Only negative frequency errors have been considered for the Demand Response model.

Conclusions Regulation techniques such as PRL can be

usefull for improving the behaviour of big wind farms in the power system.

A 1% curtailment of the available wind power can reduce significantly the frequency fluctuations caused by wind farms.

Thank you very much for your attention!