蓄能電站發(fā)變組差動保護配置研究

何雪飛，牛聚山，劉浩，馬建軍

（1.吉林敦化抽水蓄能有限公司,吉林敦化133700；2.東北勘測設計研究有限責任公司，吉林長春130021）

蓄能電站發(fā)變組差動保護配置研究

何雪飛1，牛聚山2，劉浩2，馬建軍2

（1.吉林敦化抽水蓄能有限公司,吉林敦化133700；2.東北勘測設計研究有限責任公司，吉林長春130021）

通過對抽水蓄能電站繼電保護特殊性的分析，對電站繼電保護裝置性能及接線提出基本要求。針對抽水蓄能電站繼電保護高度依賴機組運行工況特點，本文根據(jù)蒲石河抽水蓄能電站繼電保護運行經驗，提出了一套簡單可靠的繼電保護運行工況切換邏輯，并對抽水蓄能電站發(fā)電機變壓器縱聯(lián)差動保護的配置及接線方案進行分析比較，提出優(yōu)化建議方案，供同行參考。

抽水蓄能電站；發(fā)變組繼電保護；配置優(yōu)化

1 發(fā)變組差動保護的特殊性

蓄能機組具有運行工況多且轉換頻繁，機組除作為發(fā)電機運行外,作抽水運行時，變?yōu)殡妱訖C運行，機組反向旋轉，電動機的交流電流、電壓相序與發(fā)電機相反。發(fā)變組差動保護裝置需要適應運行工況，自動進行相序匹配，使差動保護能正確工作。

另外，由于蓄能機組較常規(guī)發(fā)電機組增加了水泵啟動工況,機組由靜止啟動過程中,電動機和連接母線及電壓互感器、電流互感器等都承載低于工頻的電流、電壓。差動保護裝置必須保證低頻率下合理運算，避免誤輸出。

在水泵工況下,水泵SFC啟動、背靠背啟動、電制動等每種穩(wěn)定工況或過渡工況需要投人的保護各不相同,發(fā)變組差動保護裝置需根據(jù)工況信息確定保護的投退。

2 基本要求

按照《繼電保護和安全自動裝置技術規(guī)程》、《水力發(fā)電廠繼電保護設計規(guī)范》、《國家電網公司十八項電網重大反事故措施》（修訂版）防止繼電保護事故的有關規(guī)定,抽水蓄能電站繼電保護應滿足以下的基本要求：

1）為了提高保護系統(tǒng)的可靠性和可用率，便于設備的維護和檢修，發(fā)電電動機、主變壓器保護應按雙重化配置（非電量保護除外），配置完全獨立的兩組保護；電流互感器和電壓互感器的二次回路應相互獨立，并具有較好的低頻特性；電源和出口繼電器也應相互獨立；保護范圍應交叉重疊，避免死區(qū)；每組保護應布置在不同的屏體內。

2）差動保護裝置的采樣頻率應保證在發(fā)變組區(qū)內故障情況下保護正確動作，并留有足夠裕度；機組保護應采用合適的算法，使保護裝置在機組起動到甩負荷的頻率范圍內，能保持完好的性能和靈敏度。

3）當機組工況轉換引起相序改變時，保護裝置應根據(jù)換相開關信號,通過保護軟件運算匹配相序。

4）為了防止保護在運行工況轉換中被誤閉鎖，保護系統(tǒng)應根據(jù)可靠外來獨立信號，進行投運或閉鎖。

5）保護裝置應具有保護、測量、故障錄波和時鐘同步功能，含有邏輯跳閘電路、緊急停機電路、閉鎖電路、電源、測量和測試以及信號監(jiān)視等部件；應配有開關量輸入通道，并具有與電站監(jiān)控系統(tǒng)的通信及與電站繼電保護信息網絡的通信接口。

6）保護系統(tǒng)的硬件和軟件應具有完善的自動檢測功能、容錯功能和動作記錄存儲功能，以提高保護系統(tǒng)的可靠性；保護裝置在單元件損壞時不誤動。

3 發(fā)變組差動保護投/退切換邏輯設計

抽水蓄能發(fā)變組差動保護裝置保護范圍一般包括換相開關等部件,換相開關在“發(fā)電”、“抽水”工況切換時，將引起保護裝置輸入電壓、電流相位的改變，發(fā)變組差動保護在水泵啟動工況時，由于差回路中存在啟動電流而引起保護誤動，為此一般應將該保護閉鎖。閉鎖條件可由計算機監(jiān)控系統(tǒng)提供，為滿足繼電保護高可靠性的要求,建議利用保護裝置本身的開關量輸入通道及裝置內邏輯編程功能，將反映機組運行狀態(tài)的發(fā)電機換相開關Q9、出口斷路器Q0、短路開關Q6、拖動開關Q92、被拖動開關Q91等輔助開關信號接點，輸入到保護裝置內部,經過保護裝置邏輯組合，編制出機組背靠背拖動運行工況、機組抽水被拖動啟動工況、電氣制動工況等運行工況，以此條件閉鎖發(fā)變組差動保護。

圖1 發(fā)變組差動保護閉鎖條件及邏輯圖

機組背靠背拖動運行工況的必要條件是：換相開關Q9分斷；出口斷路器Q0合閘；被拖動開關Q91分閘；拖動開關Q92合閘等。

機組抽水被拖動啟動工況的必要條件是：換相開關Q9水泵工況；出口斷路器Q0分閘；被拖動開關Q91合閘；拖動開關Q92分閘。發(fā)變組差動保護閉鎖工況條件及邏輯圖如圖1所示，當邏輯輸出為“1”時，保護被閉鎖。由于控制邏輯的輸入信號直接來自一次設備，保護裝置直接參與邏輯運算，與計算機監(jiān)控系統(tǒng)送出的工況條件相比，具有簡單、可靠、實用等特點。

4 配置及優(yōu)化

抽水蓄能電站應分別配置發(fā)電電動機差動保護和主變壓器差動保護。主保護及后備保護雙重化配置（A套、B套）；2套保護分別通過跳閘矩陣出口繼電器的兩付觸點，同時作用斷路器的2個跳閘線圈，以確保故障情況下主設備安全切除。

4.1 發(fā)電電動機縱聯(lián)差動保護

發(fā)電電動機（87GM-A，87GM-B）縱聯(lián)差動保護作為發(fā)電電動機定子繞組內部及其引出線相間短路故障的主保護，保護采用比例制動特性原理。保護瞬時動作于發(fā)電電動機出口斷路器、滅磁開關跳閘，并停機。

4.2 主變壓器縱差動保護

主變壓器縱差動保護（87T-A，87T-B）作為主變壓器內部及引出線短路故障的主保護。保護裝置應具有對區(qū)外短路的比率制動特性，具有對勵磁涌流二次諧波制動和躲避外部短路時所產生不平衡電流的能力。保護瞬時動作于主變壓器高壓側斷路器、高壓廠用變斷路器、SFC輸入斷路器、發(fā)電電動機斷路器跳閘，對發(fā)電電動機發(fā)出停機、滅磁命令。

4.3 發(fā)變組縱聯(lián)差動保護配置及其接線改進

我國早期建成的抽水蓄能電站，發(fā)電機、變壓器分別配有縱聯(lián)大差及小差保護各一套，大差保護的保護范圍包含被起動母線和起動母線，當機組抽水工況啟動時，由于大差回路中存在啟動電流，該電流約占發(fā)電機額定電流10%，會使差動保護靈敏度降低或引起誤動。當機組水泵工況啟動時，必須將大差保護退出，如若小差保護又因檢修退出時，發(fā)電機、變壓器將無法繼續(xù)運行。為解決此類問題，可采取兩種解決方法：

1）增加保護的冗余度

發(fā)電機、變壓器分別配置2套大差及2套小差動保護。發(fā)電機裝設縱差保護(87GM-A，87GM’-A，87GM-B，87GM’-B)，其中87GM’-A與87GM’-B保護范圍包含被拖動開關Q91和拖動開關Q92及其相關母線，在同步拖動和被拖動過程中退出。保護動作于停機。

變壓器裝設縱差動保護(87T-A，87T’-A，87T-B，87T’-B)作為主變壓器內部及引出線短路故障的主保護。保護裝置應能滿足多端CT接入要求。其中87T’-A和87T’-B保護范圍包含換相開關、被拖動開關Q91和拖動開關Q92及其相關母線，在同步拖動和被拖動過程中退出。保護瞬時動作于斷開主變壓器各側斷路器并停機。保護配置方案見圖2所示。

圖2 雙冗余發(fā)變組繼電保護配置圖

增加保護冗余度方案的優(yōu)點：使用1套保護裝置硬件設備和使用三組電流互感器，通過軟件編程，可組成大差、小差2套保護，相互切換。正常運行時大差保護，在同步拖動和被拖動過程中退出大差，投入小差，保證發(fā)電機、變壓器等設備始終具有2套主保護。

該方案的缺點是增加了保護裝置運行軟件的開銷，還需要在發(fā)電機主引出母線上增加4套電流互感器（12只）及其引出電纜，不但增加建設投資，而且增加了外部接線的復雜性。

2）改變微機差動保護的運算條件，控制差動保護裝置的保護范圍

微機型主變繼電保護裝置一般采用多端電流輸入。每端輸入電流的極性、相位、量程等都可通過軟件編程實現(xiàn)靈活控制，還可以通過外接開關量閉鎖各端輸入電流不參與保護運算（西門子電氣公司7UT635差動保護就具備此功能）。據(jù)此，我們可以分析抽水蓄能機組的2種運行工況：

當機組處于被拖動工況時，其GCB處于分閘狀態(tài)；當機組處于拖動工況時，其換相開關處于分斷狀態(tài)。在上述2種工況下，發(fā)電電動機與主變低壓側處于分斷狀態(tài)，對于主變壓器4端電流差動保護，發(fā)電電動機母線支路CT電流應該為0，發(fā)電電動機側CT電流不參與主變差動回路的電流運算，主變壓器4端電流差動保護變?yōu)?端電流差動，主變差動高壓側電流、SFC支路電流及高廠變支路電流仍然構成完整差動保護，不影響變壓器繼電保護功能，整套保護不需退出，保護范圍由發(fā)電機支路CT處退到斷路器（或換相開關）的上斷口。

該方案優(yōu)點是接線簡單，保護范圍不受小差CT位置的影響，從圖3可見，勵磁變、換相開關及主變低壓側電壓互感器等均不會退出，保護范圍大。蒲石河抽水蓄能電站安裝調試期間，已按上述方案對主變大差保護進行了修改，運行情況良好。

圖3 優(yōu)化的發(fā)變組縱差動繼電保護配置圖

總結蒲石河工程經驗，抽水蓄能電站發(fā)變組縱差動保護的優(yōu)化配置方案如圖3所示。主變差動保護配置2組大差，發(fā)電機差動保護配置2組小差，發(fā)電機差動保護與主變差動保護的兩組電流互感器在發(fā)電機出口與短路開關區(qū)間重疊配置。發(fā)電機差動保護可運行于任何工況，不必加閉鎖條件；主變兩組差動保護采用支路電流投/退控制方式，當保護運行于拖動工況、被拖動工況或電制動工況時，用保護外部形成的工況控制條件（見圖1），將主變保護裝置發(fā)電機支路CT電流退出，改變主變差動保護的保護范圍，保證主變保護的正常運行。

［1］NB/T35010-3013，水力發(fā)電廠繼電保護設計規(guī)范［S］.

［2］鄭光偉，張全勝，牛聚山，等.蒲石河抽水蓄能電站電氣二次設計［J］.水力發(fā)電，2012（5）.

［3］姜樹德.抽水蓄能電站電氣二次設備和接線特點［J］.電力設備，2004（12）.

Discussiononthereinforcementschemeofliningstructureofhydraulictunnel

XU Lan

[Abstract]In view of the lack of testing strength of the 143 segment(m ile number 8+432.00)concrete lining structure in the end of the secondary pressure tunnel of TP hydropower station in Ecuador,these reinforcement measuresare put forward to discussing.In thispaper,through the scheme comparison,the thickening lining structure ischosen as the finalselection combiningw ith the engineering practice.The demonstration and analysisof the finite element calculation show that the structuremeets the safety requirementsof the project.

[Key words]water diversion tunnel;lining structure;reinforcementmeasure;finite element calculation

Studyonthestabilityagainstslidingofdamfoundation forWatuohydropowerstation

QILi-wei,DU Xing-yang,ZHENG Yu-ling,NINGWei-qi

[Abstract]W ith the power house behind dam,the arrangement form of the W atuo hydropower station adopts the high foundation plane in upstream and the low foundation plane in downstream because of the bottom elevation control of the water diversion pipeline,which leads to the sliding problem of the double sliding surface along the dam foundation in the stability calculation against sliding of the dam foundation.In this paper,three kinds of transm ission methods are drawn up,and the anti-sliding stability calculation is carried out respectively.The final calculation results show that the resistance action ratio coefficients of the dam foundation stress distribution method can be increased by 10%than theweight distribution method.The dam body weight distribution method is too conservative,which cannot reflect truly the load distribution of the dam foundation rock.Therefore,it is reasonable to use the dam foundation stress distribution method for the special double sliding surface.

[Key words]gravity dam;dam foundation;double sliding surface stability calculation;resistance action ratio coefficients;W atuo hydropower station

DrawingpipeconstructionofPEPipecrossinghighway

ZANG De-xuan

[Abstract]For the first time,draw ing pipe construction method is applied let part PE pipe in network laying to crossing the highway for the 300,000 tonswater supply project in Lanshan district of Linyi City.In thispaper,the technologymeasuresin the construction processare introduced in detail,the inspection shows that the construction quality of crossing the highway isbetter,which could achieve the good social,econom ic and ecologicalbenefits.

[Key words]PE pipe;draw ing pipe construction;crossing;highway

ConstructionschemeoptimizationofDahuofangreservoirwater conveyance(phaseII)projectcrossingtheDaliaoheriver

WANG Yong-hai

[Abstract]At present,the long-distancewater conveyance projectsare being builtmore andmore in the country, the water conveyance pipeline is inevitable to cross the rivers,highways,railways and other transportation hub, and then the pipe jacking construction isw idely used.The paper describesbriefly the comparison and selection of construction schemes for the Dahuofang reservoir water conveyance(phase II)project crossing the Daliaohe river and recommends the pipe jacking construction considering the investment,construction period,land acquisition, water supply and other factors.The desired purpose isachieved based on the construction effect.It isvery effective to adopting the pipe jacking construction method under the suitable geological conditions when the water conveyance pipeline crossing the rivers.

[Key words]Daliaohe river;long distance water conveyance project;construction scheme;Dahuofang reservoir

Safetymeasuresofcollapsecavitytreatmentintunnelconstruction

DONG Bing

[Abstract]The surrounding rock collapse isoften happen in the processof the tunnel excavation,how to quickly and properly handle the collapse to ensure the follow-up safe construction is key.The paper elaborates the large crosssection collapse cavity situation in the excavation processof themain tunnel10#for the Dahuofang reservoir water conveyance project,analyzes the causes of collapse and discusses the detailed treatment measures for the collapse cavity,which could provide the references for sim ilar projects.

[Key words]tunnel;collapse cavity;treatmentmeasure;Dahuofang reservoir water conveyance project

ApplicationofimprovedfuzzyCmeansclusteringmethodinthe clusteranalysisofwatersavingirrigationlevel

WANG Tong-xu,WANG Tie,LEIGuan-jun

[Abstract]The paper elaborates the basic principlesof the fuzzy C means clusteringmethod for the clustering the samples,analyzes the existing problemsof the fuzzy C means clusteringmethod that can not determ ine the number of clusters effectively,puts forward the improvement of the fuzzy C means clustering method in the prem ise of the clustersnumber is calculated by using the dynam ic clusteringmethod.The improved fuzzy C means clustering method is used to carry out the cluster analysis for the water-saving irrigation level in a certain area,the results show that the fuzzy C meansclusteringmethod has the high applicability.

[Key words]fuzzy C means clustering method;dynam ic clustering method;inconsistency coefficient;index system ofwater saving irrigation

Protectionresearchonwaterhammerofwaterconveyance projectwithhighliftandlargeflow

MA Jun-bin

[Abstract]The paper introduces the characteristics of the water hammer produced in the long distance water conveyance condition w ith the high liftand large flow and studies themain algorithmsofwater hammer.The paper researches the hydraulic problems of the water conveyance w ith the high lift and large flow according to the selection of pipe roughness degree and the decompression of water conveyance w ith the high lift and large flow, and introduces the water hammer produced easily in the water conveyance w ith the high lift and large flow. Taking some an engineering project as an example,the computer analog simulation method is used to research the prevent effect of water hammer under the differentmeasures,which has certain instructive effect on the safe operation of the sim ilar projects.

[Key words]high lift;large flow;water hammer;protection measures

Based on the large water conveyance pipeline crossing the Beijing-Harbin railway project,considering the requests of the open digging is strictly prohibited on both sidesw ithin 30m of the high-speed rail and the design thicknessof soil cover adopt the 0.8m,the partial upheaval and offset are happen because of the too small cohesive force of the natural soil in the process of the pipeline jacking,then natural soil need to replacement. However,the natural soil is not considered to replacement in the design process of the pipeline jacking.The paper analyzesand discusses the stress situation of the processof soil cover replacement at the top of the pipeline and the confined water stress in the service processof the pipeline.

pipeline jacking;soil cover replacement;crossing;confined water;largewater conveyance pipeline

TV743；TM773+.4

B

1002－0624（2017）07－0068－03

2017-03-20

Studyonthestressunderdynamicloadoflargewaterconveyance pipelinecrossingthehigh-speedrailway

CHEN Tao-tao