- 學位論文
虛擬同步發電機控制策略補償頻率驟降事故之研究
Research on virtual synchronous generator control strategy to compensate the frequency drop event
摘要
一般電力系統當中，穩定情況下負載端與發電端處於平衡狀態，使頻率穩定維持在一定範圍內。然而當事故發生時，如用戶端瞬間加減載或是發電機組事故跳脫，皆會影響整體的電力系統的頻率變化。早期的系統架構中，傳統發電機組，如燃煤發電機、燃氣發電機、核能發電等等其機組內本身具有轉子的旋轉慣量，在發生發電機組事故或負載端加減載時，其內部轉子的旋轉慣量可作為功率的即時補償，以減緩頻率變化率。然而現今環境保育的意識抬頭，大量傳統發電機組逐漸被再生能源(Renewable Energy Sources, RESs)所取代，例如太陽能發電、風力發電等等，由於大部分的再生能源主要是以電力電子元件(如逆變器、轉換器等)的方式與電網做連接，因而導致電力系統內的整體慣量逐漸下降，進而在遭遇機組事故或負載擾動的現象時，頻率的變化尤為劇烈，容易產生低頻卸載或局部斷電的問題，使整體的電網系統更加敏感脆弱。 為因應再生能源占比逐年攀升，導致慣量不足的問題，本論文將利用電池儲能系統(Battery Energy Storage System, BESS)作為輔助裝置，並採用虛擬同步發電機(Virtual Synchronous Generator, VSG)的控制架構進行慣量補償，當儲能系統偵測到事故發生時，可以立即吸收或釋放部分功率進行補償，如同產生“虛擬”慣量效果，來減緩劇烈的頻率變動，維持系統穩定，減少低頻卸載或停電的問題發生。 儲能系統以虛擬同步發電機控制的方式中，其參數上的設定會直接影響其事故發生時輸出有效功率的大小以及運作的時間，也會對儲能系統本身以及電網中的頻率變化有直接影響，故本論文將設計一組電力系統，並基於虛擬同步發電機控制架構的儲能系統，分析在不同參數設定下其輔助效果，以此同時探討儲能系統的使用情形，並設計出在維持最低頻率限度的情況下，使儲能系統以較有效率的方式進行運作。最後本研究將利用台灣電力公司預估民國114年尖峰時段的用電情形進行事故模擬，來驗證儲能系統的成效及不同參數下的使用效果。
並列摘要
In the general power system, the generator output power and load demand are in a balanced status under stable conditions. That is, generator output power is equal to the load consuming power. Thus, the frequency is stable and maintained within a certain range. However, when an accident occurs, such as an instantaneous load increasing(or decreasing) at the demand side or generator set failure, it will lead to frequency oscillation of the overall power system. In the traditional power system, traditional generators, such as coal generators, gas turbine generators, nuclear power, etc., have the rotational inertia in the unit itself. When a sudden accident occurs like suddenly loaded or unloaded, the rotational inertia of the rotor inside the unit can be used as an instantaneous compensation of power to slow down the frequency change rate. However, due to the awareness of environmental conservation, a large numbers of traditional energy generator units are gradually being replaced by the renewable energy, such as solar power, wind power, etc. Most of the renewable energy is mainly composed of power electronic components (inverters, converters, etc.) which is connected to the power grid, so that the overall inertia in the power system gradually decreases, and then when a unit accident or load disturbance occurs, the frequency change is more drastic, which will prone to load shedding or partial power failure, also will lead to the overall system more sensitive and fragile. In order to deal with the increasing proportion of renewable energy sources in recent years, resulting in insufficient inertia, this thesis proposes a method assisted by battery energy storage system (BESS) and adopts a virtual synchronous generator (VSG) control structure for inertia compensation. When the energy storage system detects an accident or fault, it can immediately absorb or release a certain amount of active power for compensation to slow down drastic frequency changes, such as having “virtual” inertia. It can maintain system stability and reduce the probability of load shedding or power outage problems. In an energy storage system controlled by VSG, the setting of its parameters will directly affect the effective output power and operating time during the accident period. It will also affect the battery energy storage system itself and the frequency in the power grid. The parameter has a direct impact on VSG operating result, so this thesis will design and construct a set of power systems, using a battery energy storage system based on a VSG control structure to analyze the BESS effects under different parameter settings. Finally, an accident simulation will be carried out by using Taipower estimated 2025 Taiwan power network structure to verify the effectiveness of the battery energy storage system and the operation effect under different parameters.
參考文獻
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