摘 要 近年來,由於高科技產業對電力品質之要求甚高,一些不良電力品質因素如電力諧波(Harmonics)、電壓驟降(Voltage sags)、電壓升(Swell)、電壓閃爍(Flickers)及三相不平衡(Three-phase unbalance)等皆會對電機、電子及通訊設備造成長期危害。另直流偏壓也會影響變壓器的性能,而低壓用戶的負載會產生部份直流偏壓,此與地磁所感應引起的直流有類似的效應,即造成飽和的問題。 本論文利用Elgar Model SW5250交流電壓產生器及ADX3010電力品質分析器以不同直流偏壓波形對單相非晶質鐵心桿上25KVA之變壓器做開路及短路試驗,可得到變壓器在不同直流偏壓下之銅損、鐵損。本文中測試電壓有效值從40V ~ 120V來分析比較。本文實驗中所量測得到的數據包括原始輸入電流、輸入電壓波形及經ADX3010電力品質分析器運算後之各種損失(P)及電流電壓值。從本實驗中所得到的結果可以發現,直流偏壓對於台電目前使用中單相變壓器所造成的損失增加量之影響,及電壓、電流波形之變異。
ABSTRACT In recent years, the quality of electrical power supply had getting worse, some poor power quality factors such as harmonics, voltage sags, swell, flickers, and three-phase unbalance will do long-term harm to electricity engineering, electronics, and communication equipments. In addition, dc bias will also affect the function of transformers. This dc bias can be from loads of low-voltage users, also con be from earth magnetic field induction. This research uses Elgar Model SW5250 AC voltage generator and ADX3010 power quality analyzer to test a 25KVA single-phase Amorphous Metal Cored Transformers under different DC offset waveforms in open circuit and short circuit experiments. The paper analysis and comparison the test results obtained under different dc offset values, the measured data including : initial input current, input voltage waveform. From the results of the experiment, it can be found that dc bias really influences single-phase transformer to cause additional losses.