Inställning av automatikermed spänningsreglerande verkani det sydsvenska 400-130 kV nätet
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The voltage level in the power grid varies due to variations in load and production. Normally these variations are manageable, but they may be excessively large during a disturbance. If the voltage is too high it may damage the equipment in the grid and too low voltages may cause problems like voltage instability. The magnitude of the voltage variation depends on the short circuit power capacity of the point of interest.This problem may become lore prominent due to automatic voltage regulation that acts on shunt reactors and shunt capacitors. When the shunt reactor is connected or disconnected to the grid it may cause such large changes in the voltage that the shunt reactor starts hunting. Hunting is a phenomenon that manifests itself in a sequence of undesired connection and disconnection of some reactive compensation equipment connected in shunt. Hunting may also include shunt capacitors, and the emergency power and special protection schemes that acts on the HVDC links may increase the hunting problem.An earlier master thesis done at Svenska Kraftnät analysed the hunting problem in the middle parts of Sweden. Svenska Kraftnät now finds it suitable to analyse the problem with hunting for the southern part of Sweden.The main task in this master thesis is to present new settings for the automatic voltage control in the southern parts of Sweden, 400-130 kV. The purpose of this is to minimize the risk encountering of hunting. The thesis should also include an inquiry of reversed voltage control. The purpose of this is to raise the voltage limit that controls the activation of shunt capacitors in Sydkraft’s 130 kV grid and evaluate the impact of this action on the hunting problem.The work will be performed with the real time simulator ARISTO.One of the major findings of this thesis work can be summarized as follows.Due to a fairly wide range of operation conditions, finding a single set of optimal settings for the voltage automatics appears to be infeasible, at lest in general. But there are settings that can reduce the risk with hunting e.g. to separate the time settings in buses close to each other.
Place, publisher, year, edition, pages
2005. , 91 p.
EES Examensarbete / Master Thesis, X-ETS/EES-0515
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-118082OAI: oai:DiVA.org:kth-118082DiVA: diva2:604569
Master of Science in Engineering - Electrical Engineering
Ghandhari, Mehrdad, Professor