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本次设计的课题是ZY1市郊110kV变电站电气一次部分设计，该站建成后与110KV电网相连，具有110KV、35KV、10KV等三个电压等级，35KV、10KV线路以接受区域小水电电力为主，区域小水电电力大部分向110KV主网输送，小部分就地消化。本变电站位于ZY1市郊区，向市区工业、生活及郊区乡镇工业与农业用户供电，为新建变电站。110kV母线主接线形式为单母线分段，110kV出线2回，主变压器2台，总容量2×50MVA，自然油循环风冷，有载调压变压器；10kV母线主接线形式为单母线分段，10kV出线14回，每回线路长度5km，导线LGJ-240，负荷5000kVA。所址地理位置及环境条件。站址地区海拔高度200m，地势平坦，地震烈度6度。年最高气温＋40℃，年最低气温-20℃，最热月平均最高温度+30℃，最大复冰厚度10mm，最大风速25m/s，土壤热阻率ρt=100℃·cm/W，土壤温度20℃，地下水位较低，水质良好，无腐蚀性。
10KV侧装设两台站用变压器，分别接于两分段母线上，平时两台站用变压器分列运行，当一台站用变出现故障，分段断路器由自投装置动作合闸，实现备用。由于本站35KV、10KV线路所接的机组大部分为同步电机，具有调相功能，故不考虑无功补偿问题。本变电站配电装置采用普通中型配电装置，110KV及35KV采用断路器单列布置，将隔离开关放置母线下，使其与另一组隔离开关电器距离增大，缩短配电装置的纵向距离。主变中性点及出线均装设避雷器，中性点经隔离开关直接接地，并装设有两段零序保护及放电间隙保护。
关键词：变电站；主变压器：电气设备；保护设计
The subject of this design is the preliminary electrical design of a 110KV substation， which is connected to the 110KV network after its completion. It has three voltage-grade lines， such as 110kV， 35kV， 10KV， and 35kV / 10KV， which are mainly composed of receiving regional small hydropower power， most of which are transmitted to the 110KV main network. A small portion is digested locally. The substation is located in the suburb of ZY1. It supplies electricity to the industrial， rural and rural industries and agricultural users in the urban area and the suburbs. The main wiring form of the new substation. 110kV busbar is a single busbar sub-line with 2 main transformers， with total capacity. 2 × 50MVA， natural oil circulating air cooling， main connection form of 10kV busbar of load regulating transformer is 14 times of single busbar section 10kV， length of each circuit is 5km， conductor LGJ-240， load 5000kVA. Location and environmental conditions. Site area 200 m altitude， flat terrain， earthquake intensity of 6 degrees. Annual maximum temperature of + 40 ℃， annual minimum temperature of -20 ℃， maximum monthly mean maximum temperature of 30 ℃， maximum icing thickness of 10 mm， maximum wind speed of 25 m / s， soil thermal resistance of ρ _ t ~ (100 ℃) cm / w， soil temperature of 20 ℃. In 2000， the groundwater level was low， the water quality was good and non-corrosive.
Two station transformers are installed on the 10KV side， respectively connected to the two segment busbars， and usually the two stations are operated separately by transformers. When one station has a fault， the segmented circuit breaker is operated by the automatic switchgear to realize the standby. Since most of the units connected to the 35kV / 10KV line are synchronous motors with phase modulation function， reactive power compensation is not considered. The substation distribution device adopts ordinary medium distribution device (110KV) and 35KV adopts single row arrangement of circuit breaker. The switchgear is placed under the busbar to increase the distance between the switchgear and another group of isolating switchgear and shorten the longitudinal distance of the distribution device. Main transformer Lightning arresters are installed at both the performance point and the outlet line， the neutral point is directly grounded by the isolator， and two sections of zero sequence protection and discharge gap protection are installed.
Key words: substation; main transformer: electrical equipment; protection design
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