【正文】 to prevent damage to equipment. EMeter in and around the RS232 port RS232 installation of the overvoltage surge protector. Location should choose to install electronic power meter in and around the port, RS232. The location of protection: electronic power meter through the acquisition of information on the collector39。s MODEM (modem) from telephone lines to send data to a remote, since the introduction of telephone lines from the outside, the lines on the sensor to sensor lightning current relatively strong, easy to Modem interface equipment damage, it is necessary in the telephone line modem interface, the installation of an interface overvoltage surge protector. Location should choose to install telephone Chuxian inside and outside phone linestheline people. distance munication interface overvoltage protection Protective position: Since the basic use of unmanned substation. On the first circuit protection, measurement, control, regulation of signal through the optical and data munications work or carrier to the distance (in tune, and stressed that the centralized control stations, etc.) to transmit data. If the carrier, the carrier and the puter automation of the signal devices connected relatively long lines, substations in the vicinity of a direct lightning strike or be a strong overvoltage sensors, to be near the puter automation devices to signal I: Ithe installation of signal arrester, while in the area and extend to LPZOB LPZOA area of munication lines (DDN, ) very easy Lightning sensors on the overvoltage, must also be the installation of overvoltage surge protector. Installation location should choose the remote device munication line interface Department. Secondary system overvoltage substation protection issues in recent years by a new task, the above is only related to the scene of the unit into the actual situation on the Protection of the preliminary measures, it will be in continuing to draw on practical experience of running a summary analysis and continuous improvement, Hope that the new substation in the future or the old substation automation of integrated, strengthen the secondary overvoltage protection system of planning and design, equipment and ensure the safe and stable operation of power grids. 變電站系統(tǒng)過電壓防護(hù)技術(shù) 變電站的過電壓保護(hù)是以電子信息系統(tǒng)為保護(hù)核心，為被保護(hù)設(shè)備構(gòu)建一個均壓等電位系統(tǒng)，并通過各級過電壓浪涌保護(hù)器逐級把電流泄放入大地，使變電站設(shè)備安全和可靠地運行。變電站內(nèi)的過電壓形式主要有：雷電過電壓、工頻過電壓及諧振過電壓、操作過電壓等，這些過電壓以傳導(dǎo)或電磁感應(yīng)的方式在線路及設(shè)備上形成危險的過電壓，特別是雷電 過電壓，雷擊變電站時，會在低壓供電系統(tǒng)及弱電系統(tǒng)產(chǎn)生很強的感應(yīng)過電壓，同時使變電站的地電位升高 (例如：變電站的接地電阻為 1 Q，雷電流為 10 kA，則地電位為 10 kV)，因地電位升高造成對線路及設(shè)備的反擊而損壞線路及設(shè)備的事件時有發(fā)生，因此，盡管變電站的外部防雷系統(tǒng) (避雷針．引下線及接地裝置 )符合國家及部頒標(biāo)準(zhǔn)的要求，且其綜合自動化和通信自動化等二次弱電系統(tǒng)也采取了諸如屏蔽、接地、隔離、濾波等措施，但卻不能完全避免強大的雷電過電壓及電壓反擊對系統(tǒng)造成的干擾和破壞，因此，變電站二次弱電系統(tǒng)內(nèi)部防雷及過電壓也 必須采取相應(yīng)的防護(hù)措施，按照 IEC 內(nèi)部防雷 EMP 的分區(qū)，對設(shè)備的電源線、信號線、數(shù)據(jù)線等加裝內(nèi)部防雷及過電壓器件，防止雷電感應(yīng)、雷電流沿線竄人、電壓反擊、浪涌過電壓等瞬間暫態(tài)過電壓造成系統(tǒng)故障及損壞電子設(shè)備。根據(jù)變電站的現(xiàn)狀，對變電站的二次系統(tǒng)感應(yīng)雷及操作過電壓采用兩級防護(hù)。安裝位置宜選擇在直流充電屏交流電源空氣開關(guān)處。與這些設(shè)備相連的有信號線、數(shù)據(jù)線、測量和控制線路，并且這些線路基本上是處于 LPZOB 區(qū)域，也有穿過 LVZOA 區(qū)域的，線路上的感應(yīng)過電壓相對較強，根據(jù) IEC 的測試，當(dāng)電磁場強度增大到 0． 07GS 時，微型計算機設(shè)備將產(chǎn)生誤動，丟失數(shù)據(jù)。由于電能表與站內(nèi)微機遠(yuǎn)動設(shè)備的通信采用 RS232 的接口，其通信線路較長，又處在 LVZOB區(qū)域，在變電站附近或變電站遭受直接雷擊時，將感應(yīng)出較強的感應(yīng)過電壓，為了防止設(shè)備的損壞。安裝位置宜選擇在遠(yuǎn)動裝置通信線路接口處。對一次回路的各種保護(hù)、測量、控制、調(diào)節(jié)信號通過光纖、數(shù)據(jù)通信網(wǎng)絡(luò)或載波向遠(yuǎn)方 (省調(diào)、地調(diào)、集控站等 )傳送數(shù)據(jù)。安裝位置宜選擇在微機遠(yuǎn)動裝置通信線路接口處。 3． 4 通信接口過電壓防護(hù) 通信接口過電壓防護(hù)同電網(wǎng)供電系統(tǒng)相比，此回路對過電壓的敏感程度要高得多，且這些設(shè)備在有過電壓的情況下顯得非常脆弱。 3． 1． 2 第二級防護(hù)處理措施 對于較為重要的交流饋線上的設(shè)備，此處為直流充電屏，加裝 c 級三相電源避雷器。 B 級防雷一般采用具有較大通流容量的防雷裝置，可以將較大的雷電流泄散 人地，從而達(dá)到限流的目的，同時將過電壓減小到一定的程度， c 級防雷采用具有較低殘壓的防雷裝置，可以將回路中剩余的雷電流泄散人地，達(dá)到限制過電壓的目的，使過電壓減小到設(shè)備能耐受的水平。 2 過電壓保護(hù)設(shè)計 IEC(國際電工委員會 )TC／ 81 技術(shù)委員會將防雷分為外部防雷和內(nèi)部防雷兩個部分 ，外部防雷是指避雷針 (或避雷帶、避雷網(wǎng) )、引下線和接地系統(tǒng)，是被保護(hù)物體免受直接雷擊；內(nèi)部防雷則是防止雷電和其他內(nèi)部過電壓侵入設(shè)備造成的毀壞。s segregation measures, because its grounding, protection and other electrical grounding all Grounding devices using the same equipment, and equipment are in a LPZOB, the relative strength of strong electromagic pulse, the station changed to prevent lowpressure side although there are lines intrusive wave arrester, but the residual pressure high, in the substation of lightning, through the line Coupling and the potential rise caused by overvoltage counterattack still