Aggregation and Control of Flexible Thermal Demand for Wind Power Based Power System Analysis
Author
Tróndheim, Helma Maria
Term
4. term
Education
Publication year
2018
Abstract
Dette speciale undersøger, om fleksibelt termisk forbrug i form af aggregerede varmepumper kan bidrage til sekundær frekvensregulering i et vinddomineret, isoleret elsystem med udgangspunkt i Færøerne, som sigter mod 100 % vedvarende onshore energi i 2030. Et net med diesel- og vandkraftenheder samt vindkraft er modelleret i DIgSILENT PowerFactory, og der er udviklet og valideret en varmepumpemodel. Med en load frequency controller (LFC) gennemføres dynamiske simuleringer baseret på målte belastninger, vejrdata og varmebehov for vinter- og sommerdage med forskellige vindandele (op til ca. 50 % af det daglige elforbrug). Uden vind eller med konventionelle enheder og LFC blev frekvensen genoprettet til 50 Hz efter ubalancer og holdt inden for ca. 49,87–50,07 Hz. Tilføjelse af vindkraft øgede afvigelserne til omkring 49,5–50,3 Hz, hvilket indikerer en negativ påvirkning af frekvensbalancen. Inkludering af varmepumper i LFC gav kun små, i praksis ubetydelige forbedringer, og minimums- og maksimumsfrekvenserne blev generelt ikke forbedret. De beskedne gevinster tilskrives bl.a. controllerbegrænsninger og en i forvejen relativt stabil frekvens i de analyserede scenarier.
This thesis examines whether flexible thermal demand, represented by aggregated heat pumps, can support secondary frequency regulation in a wind-dominated, islanded power system, using the Faroe Islands’ pursuit of 100% onshore renewables by 2030 as context. A grid with diesel and hydro generators plus wind power was modeled in DIgSILENT PowerFactory, and a heat pump model was developed and validated. A load frequency controller (LFC) was implemented, and dynamic simulations were run for winter and summer days using measured load, weather, and heat demand data, with wind shares up to about 50% of daily energy. With conventional units and LFC, the system restored frequency to 50 Hz after disturbances and maintained it within approximately 49.87–50.07 Hz. Adding wind increased deviations to roughly 49.5–50.3 Hz, indicating a negative impact on frequency balance. Incorporating heat pumps into the LFC yielded only minor, practically negligible improvements, and minimum/maximum frequencies were generally not improved. The limited gains are attributed to controller constraints and an already relatively stable frequency under the studied conditions.
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