陳繼勇 徐文亮 鄭 杰

（成都地鐵運(yùn)營有限公司，610058，成都∥第一作者，工程師）

地鐵35 kV中壓環(huán)網(wǎng)數(shù)字通信電流保護(hù)能適應(yīng)多級(jí)串行供電系統(tǒng)，具有“絕對選擇性”，解決了傳統(tǒng)保護(hù)的級(jí)差配合難題，適應(yīng)地鐵實(shí)際運(yùn)行環(huán)境，可有效實(shí)現(xiàn)地鐵中壓環(huán)網(wǎng)大分區(qū)供電。其在供電方式調(diào)整時(shí)能自動(dòng)適應(yīng)“正常供電”和“支援供電”兩種運(yùn)行方式，保護(hù)定值不再需要進(jìn)行調(diào)整，為地鐵線路快速恢復(fù)供電提供了有力保障。此外，數(shù)字通信電流保護(hù)的優(yōu)越性也對校驗(yàn)保護(hù)方案的完整性提出了更高的要求。如何對新建線路中壓環(huán)網(wǎng)數(shù)字通信電流保護(hù)進(jìn)行全面測試校驗(yàn)，為地鐵開通運(yùn)營保駕護(hù)航，是研究此項(xiàng)技術(shù)現(xiàn)場應(yīng)用的關(guān)鍵。

1 數(shù)字通信電流保護(hù)的實(shí)現(xiàn)原理

地鐵交流供電系統(tǒng)采用環(huán)網(wǎng)供電方式，每個(gè)變電所設(shè)置環(huán)網(wǎng)進(jìn)出線開關(guān)柜，并在進(jìn)出線開關(guān)柜設(shè)置線網(wǎng)電纜及母線保護(hù)。如圖1所示，數(shù)字通信電流保護(hù)常用近區(qū)加速實(shí)現(xiàn)，采用雙差動(dòng)保護(hù)形式，即后備保護(hù)裝置也兼具差動(dòng)功能。站內(nèi)進(jìn)、出線柜后備保護(hù)裝置用硬接線連接，傳遞故障定位a信號(hào)；站間差動(dòng)保護(hù)及后備保護(hù)裝置用光纖連接，傳遞過流同步開放信號(hào)。正常運(yùn)行過程中過流Ⅲ段永久運(yùn)行，過流Ⅰ段處于閉鎖狀態(tài)，通過a信號(hào)判斷是否開放過流Ⅰ段。在后備保護(hù)中，定義內(nèi)部故障定位信號(hào)a，當(dāng)本柜后備保護(hù)裝置差動(dòng)未啟動(dòng)且檢測到大電流時(shí)定義a=1，反之a(chǎn)=0。本柜a=1且對側(cè)后備裝置a=0時(shí)解鎖本柜過流Ⅰ段。同時(shí)通過后備光纖通道將過流開放信息發(fā)送至對端開關(guān)柜，開放對端后備裝置過流Ⅰ段，成為下級(jí)站開關(guān)失靈的后備保護(hù)。所內(nèi)饋線及母聯(lián)保護(hù)裝置不參與數(shù)字通信，通過常規(guī)時(shí)間級(jí)差實(shí)現(xiàn)保護(hù)選擇性，動(dòng)態(tài)級(jí)差確保不越級(jí)動(dòng)作。當(dāng)供電方向發(fā)生改變時(shí)，進(jìn)、出線柜功能互換，保護(hù)功能不變，故障定位信號(hào)自動(dòng)與之匹配，鎖定故障范圍。

2 測試技術(shù)

傳統(tǒng)的繼電保護(hù)測試儀主要應(yīng)用于供電系統(tǒng)中單體設(shè)備單裝置保護(hù)功能的精準(zhǔn)校驗(yàn)，在電力系統(tǒng)及地鐵供電系統(tǒng)應(yīng)用極為廣泛。目前國內(nèi)主流品牌的繼電保護(hù)測試儀售價(jià)為15萬～20萬元不等。隨著數(shù)字通信電流保護(hù)技術(shù)在地鐵環(huán)網(wǎng)供電系統(tǒng)的廣泛應(yīng)用，其保護(hù)實(shí)現(xiàn)原理決定了保護(hù)校驗(yàn)的特殊性，而傳統(tǒng)的繼電保護(hù)測試儀無法實(shí)現(xiàn)多臺(tái)設(shè)備聯(lián)機(jī)同步輸出功能，不能對數(shù)字通信電流保護(hù)進(jìn)行全面的測試校驗(yàn)。

由于數(shù)字通信電流保護(hù)的選擇性涉及多個(gè)變電所邏輯的同步判斷，任一環(huán)節(jié)出錯(cuò)將導(dǎo)致供電分區(qū)內(nèi)出現(xiàn)越級(jí)跳閘，所以實(shí)現(xiàn)邏輯功能的完整校驗(yàn)是數(shù)字通信電流保護(hù)得以可靠應(yīng)用的關(guān)鍵?？紤]到地鐵變電所所屬地下環(huán)境以及保護(hù)方法的差異性，基于GPS（全球定位系統(tǒng)）、光纖B碼等對時(shí)技術(shù)的多站同步輸出測試儀，為數(shù)字通信電流保護(hù)校驗(yàn)提供了新的測試思路。新型的繼電保護(hù)測試儀在傳統(tǒng)測試儀的基礎(chǔ)上集成配置了對時(shí)模塊，僅增加約5 000～8 000元的費(fèi)用，便可以實(shí)現(xiàn)多機(jī)同步輸出功能；同時(shí)可充分利用地鐵環(huán)網(wǎng)特有的站間差動(dòng)預(yù)留光纖，實(shí)現(xiàn)繼電保護(hù)測試儀多站同步信號(hào)發(fā)送接收，從而解決了環(huán)網(wǎng)供電系統(tǒng)站間同步聯(lián)調(diào)的難題。

圖1 環(huán)網(wǎng)進(jìn)出線開關(guān)柜保護(hù)配置圖

3 測試方法

多站同步加量測試可完全模擬實(shí)際運(yùn)營期間的各類型環(huán)網(wǎng)故障點(diǎn)位，以單元化的測試思路，在多站保護(hù)裝置進(jìn)行故障邏輯同步判斷，從而實(shí)現(xiàn)保護(hù)邏輯站內(nèi)、站間的同步校驗(yàn)。

現(xiàn)場測試以地鐵A、B、C三站同Ⅰ（Ⅱ）段母線為測試單元，A、B站放置同步加量測試儀器。利用站間預(yù)留的差動(dòng)光纖實(shí)現(xiàn)模塊時(shí)鐘同步，通過設(shè)定統(tǒng)一輸出時(shí)間實(shí)現(xiàn)繼電保護(hù)測試儀同步加量。測試順序以主變電所或開閉所電源出線為測試起點(diǎn)A站，測試主站為B站，逐站推進(jìn)；每一座變電站均在測試過程中成為主站。

結(jié)合當(dāng)前保護(hù)原理及測試方法，本文對典型故障實(shí)際測試方法及邏輯判斷進(jìn)行分析。

3.1 BC站間環(huán)網(wǎng)故障

如圖2所示，測試時(shí)，在A站103開關(guān)柜（以下簡為103，余類同）加故障電流I，時(shí)長0.4 s，硬線開入模擬103收到站內(nèi)101的a=1信號(hào)；在B站101和103加故障電流I，時(shí)長0.4 s。

圖2 區(qū)間環(huán)網(wǎng)故障示意圖

觀察分析B站103和C站101的差動(dòng)裝置、后備裝置差動(dòng)是否同時(shí)動(dòng)作。B站103差動(dòng)啟動(dòng)且有大電流a=0，B站101差動(dòng)未啟動(dòng)且有大電流a=1，因此101開放過流Ⅰ段，同時(shí)軟件開放A站103過流Ⅰ段。模擬A站103收到站內(nèi)101發(fā)出的a=1信號(hào)，上級(jí)站接收到大電流且差動(dòng)未啟動(dòng)的信息，即表明來電方向在A站。因測試加量時(shí)間0.4 s，即可模擬B站103和C站101的差動(dòng)裝置、后備裝置差動(dòng)動(dòng)作已將故障可靠切除。A站103和B站101過流Ⅰ段保護(hù)出口延時(shí)未達(dá)到，保護(hù)立即返回。模擬B站斷路器失靈，測試方法同上，通過對調(diào)整加量時(shí)長至0.6 s，模擬B站103切除故障失敗，由后備保護(hù)A站103和B站101過流I段動(dòng)作出口跳閘。

3.2 B站母線故障

如圖3所示，測試時(shí)在A站103加故障電流I，時(shí)長0.6 s，硬線開入模擬103收到站內(nèi)101的a=1信號(hào)；在B站101和103加故障電流I，時(shí)長0.6 s。

103過流Ⅰ段開放邏輯分析過程同BC環(huán)網(wǎng)故障。因測試加量時(shí)間0.6 s，即模擬A站103和B站101過流Ⅰ段動(dòng)作出口跳閘。因A站103和B站101過流Ⅰ段保護(hù)同步開放，當(dāng)B站101斷路器失靈后故障點(diǎn)仍可通過A站103予以可靠切除。

圖3 站內(nèi)母線故障示意圖

3.3 B站饋線故障

如圖4所示，測試時(shí)在A站103加故障電流I，時(shí)長0.25 s，硬線開入模擬103收到站內(nèi)101的a=1信號(hào)；在B站101和111加故障電流I，時(shí)長0.25 s。

B站101和A站103過流I段開放邏輯分析同BC環(huán)網(wǎng)故障。因測試加量時(shí)間0.25 s，即模擬B站111過流保護(hù)動(dòng)作出口跳閘。因A站103和B站101過流I段保護(hù)同步開放，當(dāng)B站111斷路器失靈，故障點(diǎn)仍通過A站103和B站101同步可靠切除。

圖4 站內(nèi)饋線故障示意圖

圖5 站內(nèi)II段母線故障示意圖

3.4 B站Ⅰ母支援Ⅱ母供電，Ⅱ母故障

如圖5所示，測試時(shí)在A站103加故障電流I，時(shí)長0.4 s，硬線開入模擬103收到站內(nèi)101的a=1信號(hào)；在B站101和110加故障電流I，時(shí)長0.4 s。

B站101和A站103過流I段開放邏輯測試分析同BC環(huán)網(wǎng)故障。因測試加量時(shí)間0.4 s，即模擬B站110過流保護(hù)動(dòng)作已將故障切除。A站103和B站101過流I段動(dòng)作延時(shí)未達(dá)到立即返回。模擬B站母聯(lián)110斷路器失靈，測試方法不變，通過對調(diào)整加量時(shí)長至0.6 s，模擬B站母聯(lián)110切除故障失敗，由A站103和B站101過流I段動(dòng)作出口跳閘。

4 結(jié)語

供電系統(tǒng)是地鐵新線建設(shè)的先頭工程和重點(diǎn)工程。一旦環(huán)網(wǎng)帶電，各專業(yè)調(diào)試將全面展開，再次大面積停電調(diào)試將嚴(yán)重影響其他專業(yè)的調(diào)試工作。因此，應(yīng)充分把握環(huán)網(wǎng)保護(hù)調(diào)試時(shí)間，系統(tǒng)性地驗(yàn)證各保護(hù)動(dòng)作的關(guān)鍵故障點(diǎn)。為使環(huán)網(wǎng)保護(hù)能得以成功應(yīng)用，離不開與之匹配的測試方法，應(yīng)充分發(fā)掘利用新技術(shù)、新設(shè)備來打破傳統(tǒng)的測試思路。多站同步加量測試技術(shù)在地鐵供電系統(tǒng)的成功應(yīng)用，從系統(tǒng)安全運(yùn)行的角度來分析模擬故障點(diǎn)位的發(fā)生，通過全面性的功能驗(yàn)證，保證了地鐵中壓環(huán)網(wǎng)供電系統(tǒng)的可靠穩(wěn)定運(yùn)行，進(jìn)而為地鐵運(yùn)營提供最有力的保障。

（收稿日期：2017-08-21）

（Continued from Commentary）

aging and generating a lot of failures，which need to be overhauled and refurbished.When it comes to signaling，due to the limitations of system mode，i.e.track circuit or intermittent ATP，or the aging of the existing system，the demand of ever growing ridership can no longer be efficiently fulfilled.

The modernization of an existing line is more complex than building a new line and faces multiple challenges.For example，we have to ensure the operation of the existing line and take the new system into consideration to allow for interfaces.Technical solutions may vary as cities are different from each other in terms of network，ridership，and signaling system.Globally speaking，in UK where the world′s earliest metro was built，the London 4 LM （Lines mondernization） is the world′s most complicated modernization project.In China，Shanghai Line 5 is the first urban rail line where operation，renovation，and construction were fulfilled at the same time.

The difficulty of resignaling resides in two aspects.Firstly，the new system replacing the old one should be as robust as the system for a new line.However，due to the constraints of the infrastructure of the existing line，many issues have to be tackled creatively.Secondly，resignaling cannot impact service or should at least keep the impact to the minimum.As there are many times of switchovers between the old and the new system，we have to ensure both safety and efficiency of commissioning.This makes it even more demanding fro system development，site deployment，and construction planning.Take Shanghai Line 5 for example.The line was originally opened in 2003.The equipment was aging and the intermittent ATP system could no longer meet the requirement of ever increasing ridership.The resignaling of Shanghai Line 5 includes not only the replacement of the the signaling system but also adding 6-car trains to run in mixed operation with the existing 4-car trains，as well as the installation of platform screen doors and renovation of auxiliary tracks.In the meanwhile，the south extension was carried out.The resignaling should have no impact on the service of the existing line.TST′s local innovation TSTCBTC?2.0 was selected for Shanghai Line 5.The system′s dual CBTC architecture enhances the core functions of signaling and helps achieve higher availability.Less wayside equipment is required，which reduces the conflict of space for outdoor facilities and suits the reality of opening in different sections and in different time.With no service disruption，the cutover between the old and new signaling system was successfully completed in Oct，2018 after more than 500 days of commissioning and over 1 000 switchovers.By the end of 2018，Shanghai Line 5 went into full line service.

The network of urban rail transport in China′s mega cities and big cities is becoming more and more mature.We are expecting fewer new lines in the future，whilst modernization of existing lines will become the new normal.Besides Shanghai，Tianjin，Dalian，Chongqing，and Guangzhou either have lines modernized or are planning for it.For urban rail operators and system integrators，it is an all-time focus of safe and efficient operation.How to ensure continuous operation with a highly available system and how to upgrade the system through highly safe modernization with little risk are what we all need to think about.The resignaling and south extension of Shanghai Line 5 made many ground-breaking achievements，providing a lot of experience that can be shared to the industry.This also sets the stage for the standardization of urban rail modernization in China.