【正文】 Many transformer bodies were displaced even dropped from mounting bases. Varying degrees of displacements can be seen in many 220kV substations, such as Yuanjiaba Substation, Tianming Substation, Dakang Substation, Yongxing Substation, Anxian Substation and Xinshi Substation. These phenomena can also be seen in many 110kV stations, such as Shengmuquan Substation, Wanchun Substation, Sandui Substation, Jiange Substation, etc. Furthermore, transformer 2 in 500kV Maoxian Substation caught fire.Most of the mounting bolts of 220kV transformers were broken inXinshi Substation in Deyang City, and the transformers were moved along the skid (see Fig. 1).As shown in Fig. 1, although 14 of 16 mounting bolts were broken in the earthquake, the fixing clips still clipped the skid hard which counteracted the horiontal force acting on the transformer, so that it could be retained firmly on the skid. If fixing clips were disabled, transformers might be off the skid and upset, resulting in extremely serious consequences. Due to the high seismic intensity, some transformers without firm fixation fell off their mounting bases. A 220kV transformer designed in 1970s fell into an oil drainage pool, resulting in bending of HV bushing, leaking of oil and local deformation of chassis (see Fig. 2). By careful inspection, it was found that the transformer had neither anchor bolts nor locating and fixing devices that providefirm connection with the mounting base.Breaking and leaking at transformer bushingsThe earthquake also caused breaking of HV and MV bushings, disconnection, dislocation or leaking of oil at the joint of flange and porcelain, which in large scale resulted in outage transformers and reactors. Bushing’ s part at the junction with angled ascending base was most damaged, while bushing’s part inside main body was less damaged. Fig. 3 is a typical picture of bushings damaged in the earthquake. Most oil leaking could be attributable to bushing damage. Therefore, it is crucial to improveBushing’s aseismatic performance.SwitchgearThere were several types of damage to switchgears caused by the earthquake, such as break and collapse, body deformation, leaking of gas, mechanical failure and so on. Damage statistics on switchgears are shown in Table 2. It can be seen from the table that the main type of damage to switchgears was breaking and collapse.Table 2 Statistics on number of switchgeardamage by typeType of damageGIS252 kVCircuit252 kVBreaker126 kVDisconnector252 kV126 kVBreaking and collapse15222942Body deformation2255Leaking of gas51Mechanical failure166Others224total423314051Damage to disconnecting switches happened mostly in epicentre area with high seismic intensity. There were fewer disconnecting switches damaged in circumjacent areas.In respect of the damage to circuit breakers, it seemed to vary with types of products. There was one set of 252kV gas insulated switchgear (GIS) involved in this investigation. The earthquake just caused a bushing incline between two cubicles and the equipment was restored soon.For traditional circuit breakers, the degree of damage related closely to their structures. At the voltage level of 252 kV, the post porcelain insulators of oldtype doublebreak SF6 circuit breakers were broken widely because of heavy top (see Fig. 4). The new type of singlebreak SF6 circuit breakers were in better conditions thanks to light top, especially for some imported porcelain products (see Fig. 5). At the voltage level of 126 kV, most of the circuit breakers were damaged slightly except the oldtype ones in epicenter area where the intensity was very high. According to the investigation, most of the switchgears at various voltage levels were made of porcelain and were of openair type, so they had bad aseismatic performance. In parison, GIS and tank circuit breakers had better aseismatic performance. Therefore they can be considered as a choice in future equipment selection for earthquake areas. Bus bars and post insulatorsThere were two kinds of bus bar in the substations, that is, hard and flexible. The hard one was made of aluminum tube and aluminum conductor, and the flexible one was made of aluminum conductor. They were damaged in different ways by the earthquake. The damage relating hard bus bars was mainly breaking of solidcore post insulators (normally made of porcelain)。 it also inflicted a heavy loss on transmission and substation facilities. In order to minimize losses on these facilities, shorten repair time,resume electricity supply as soon as possible, thus to reduce secondary losses, it is necessary to make a survey on their afterquake conditions. In addition, based on the understanding about the aseismatic performance of the facilities, meaningful countermeasures can be put forward for improving their earthquake resisting abilities. To understand the detailed status of the transmission and substation facilities of Sichuan power grid and to gain experience for earthquake after math mitigation in the future, an expert group from China Electric Power Research Institute (CEPRI) was organized and sent to Sichuan for onsite investigation from May 18 till May 21. Experts inspected some disastrous 220kV and110kV substations. They also held a symposium to exchange with some local electric panies including Sichuan Electric Power Company, Sichuan Electric Power Test amp。8) 這次地震強化重點變電站和線路鐵塔在地震帶的設(shè)計標(biāo)準(zhǔn)應(yīng)該提高，適當(dāng)?shù)膫溆迷O(shè)備和備品備件準(zhǔn)備。6) 地震減少和變電設(shè)施隔離技術(shù)的研究應(yīng)進行進行深入探討。3)這次地震減少和隔離技術(shù)，應(yīng)適用于變電站工程建設(shè)。建設(shè)者在改造前應(yīng)記錄所有變電站設(shè)備損壞的整體細(xì)節(jié)。一般而言，建筑物和變電站結(jié)構(gòu)的設(shè)計和建造根據(jù)一個給定的地震強度強化，所以他們的抗震能力是有限的。有關(guān)硬母線受損，主要是母線的實心支柱絕緣子（通常是瓷器做的）破裂；有關(guān)軟母線受損，一般是打破瓷絕緣子。因此，在未來對震區(qū)設(shè)備選擇時可以作為一個選擇。而新式的單斷六氟化硫斷路器有頂部輕而情況好一些，尤其因為有一些進口的陶瓷產(chǎn)品（見圖5）。有一個252千伏氣體絕緣開關(guān)設(shè)備（GIS）在本次調(diào)查涉及的設(shè)置。關(guān)于開關(guān)損傷統(tǒng)計見表2。圖片三就是一張典型的在地震中受損的襯套。 因為這樣高強度的地震，有些沒有固定牢靠的變壓器從基座掉下來了。另外，茂縣有二座500kV變電所起火。許多變壓器的體位移動了，甚至從基座上掉了下來。