蓄能电站发变组差动保护配置研究

何雪飞，牛聚山，刘浩，马建军

（1.吉林敦化抽水蓄能有限公司,吉林敦化133700；2.东北勘测设计研究有限责任公司，吉林长春130021）

蓄能电站发变组差动保护配置研究

何雪飞1，牛聚山2，刘浩2，马建军2

（1.吉林敦化抽水蓄能有限公司,吉林敦化133700；2.东北勘测设计研究有限责任公司，吉林长春130021）

通过对抽水蓄能电站继电保护特殊性的分析，对电站继电保护装置性能及接线提出基本要求。针对抽水蓄能电站继电保护高度依赖机组运行工况特点，本文根据蒲石河抽水蓄能电站继电保护运行经验，提出了一套简单可靠的继电保护运行工况切换逻辑，并对抽水蓄能电站发电机变压器纵联差动保护的配置及接线方案进行分析比较，提出优化建议方案，供同行参考。

抽水蓄能电站；发变组继电保护；配置优化

1 发变组差动保护的特殊性

蓄能机组具有运行工况多且转换频繁，机组除作为发电机运行外,作抽水运行时，变为电动机运行，机组反向旋转，电动机的交流电流、电压相序与发电机相反。发变组差动保护装置需要适应运行工况，自动进行相序匹配，使差动保护能正确工作。

另外，由于蓄能机组较常规发电机组增加了水泵启动工况,机组由静止启动过程中,电动机和连接母线及电压互感器、电流互感器等都承载低于工频的电流、电压。差动保护装置必须保证低频率下合理运算，避免误输出。

在水泵工况下,水泵SFC启动、背靠背启动、电制动等每种稳定工况或过渡工况需要投人的保护各不相同,发变组差动保护装置需根据工况信息确定保护的投退。

2 基本要求

按照《继电保护和安全自动装置技术规程》、《水力发电厂继电保护设计规范》、《国家电网公司十八项电网重大反事故措施》（修订版）防止继电保护事故的有关规定,抽水蓄能电站继电保护应满足以下的基本要求：

1）为了提高保护系统的可靠性和可用率，便于设备的维护和检修，发电电动机、主变压器保护应按双重化配置（非电量保护除外），配置完全独立的两组保护；电流互感器和电压互感器的二次回路应相互独立，并具有较好的低频特性；电源和出口继电器也应相互独立；保护范围应交叉重叠，避免死区；每组保护应布置在不同的屏体内。

2）差动保护装置的采样频率应保证在发变组区内故障情况下保护正确动作，并留有足够裕度；机组保护应采用合适的算法，使保护装置在机组起动到甩负荷的频率范围内，能保持完好的性能和灵敏度。

3）当机组工况转换引起相序改变时，保护装置应根据换相开关信号,通过保护软件运算匹配相序。

4）为了防止保护在运行工况转换中被误闭锁，保护系统应根据可靠外来独立信号，进行投运或闭锁。

5）保护装置应具有保护、测量、故障录波和时钟同步功能，含有逻辑跳闸电路、紧急停机电路、闭锁电路、电源、测量和测试以及信号监视等部件；应配有开关量输入通道，并具有与电站监控系统的通信及与电站继电保护信息网络的通信接口。

6）保护系统的硬件和软件应具有完善的自动检测功能、容错功能和动作记录存储功能，以提高保护系统的可靠性；保护装置在单元件损坏时不误动。

3 发变组差动保护投/退切换逻辑设计

抽水蓄能发变组差动保护装置保护范围一般包括换相开关等部件,换相开关在“发电”、“抽水”工况切换时，将引起保护装置输入电压、电流相位的改变，发变组差动保护在水泵启动工况时，由于差回路中存在启动电流而引起保护误动，为此一般应将该保护闭锁。闭锁条件可由计算机监控系统提供，为满足继电保护高可靠性的要求,建议利用保护装置本身的开关量输入通道及装置内逻辑编程功能，将反映机组运行状态的发电机换相开关Q9、出口断路器Q0、短路开关Q6、拖动开关Q92、被拖动开关Q91等辅助开关信号接点，输入到保护装置内部,经过保护装置逻辑组合，编制出机组背靠背拖动运行工况、机组抽水被拖动启动工况、电气制动工况等运行工况，以此条件闭锁发变组差动保护。

图1 发变组差动保护闭锁条件及逻辑图

机组背靠背拖动运行工况的必要条件是：换相开关Q9分断；出口断路器Q0合闸；被拖动开关Q91分闸；拖动开关Q92合闸等。

机组抽水被拖动启动工况的必要条件是：换相开关Q9水泵工况；出口断路器Q0分闸；被拖动开关Q91合闸；拖动开关Q92分闸。发变组差动保护闭锁工况条件及逻辑图如图1所示，当逻辑输出为“1”时，保护被闭锁。由于控制逻辑的输入信号直接来自一次设备，保护装置直接参与逻辑运算，与计算机监控系统送出的工况条件相比，具有简单、可靠、实用等特点。

4 配置及优化

抽水蓄能电站应分别配置发电电动机差动保护和主变压器差动保护。主保护及后备保护双重化配置（A套、B套）；2套保护分别通过跳闸矩阵出口继电器的两付触点，同时作用断路器的2个跳闸线圈，以确保故障情况下主设备安全切除。

4.1 发电电动机纵联差动保护

发电电动机（87GM-A，87GM-B）纵联差动保护作为发电电动机定子绕组内部及其引出线相间短路故障的主保护，保护采用比例制动特性原理。保护瞬时动作于发电电动机出口断路器、灭磁开关跳闸，并停机。

4.2 主变压器纵差动保护

主变压器纵差动保护（87T-A，87T-B）作为主变压器内部及引出线短路故障的主保护。保护装置应具有对区外短路的比率制动特性，具有对励磁涌流二次谐波制动和躲避外部短路时所产生不平衡电流的能力。保护瞬时动作于主变压器高压侧断路器、高压厂用变断路器、SFC输入断路器、发电电动机断路器跳闸，对发电电动机发出停机、灭磁命令。

4.3 发变组纵联差动保护配置及其接线改进

我国早期建成的抽水蓄能电站，发电机、变压器分别配有纵联大差及小差保护各一套，大差保护的保护范围包含被起动母线和起动母线，当机组抽水工况启动时，由于大差回路中存在启动电流，该电流约占发电机额定电流10%，会使差动保护灵敏度降低或引起误动。当机组水泵工况启动时，必须将大差保护退出，如若小差保护又因检修退出时，发电机、变压器将无法继续运行。为解决此类问题，可采取两种解决方法：

1）增加保护的冗余度

发电机、变压器分别配置2套大差及2套小差动保护。发电机装设纵差保护(87GM-A，87GM’-A，87GM-B，87GM’-B)，其中87GM’-A与87GM’-B保护范围包含被拖动开关Q91和拖动开关Q92及其相关母线，在同步拖动和被拖动过程中退出。保护动作于停机。

变压器装设纵差动保护(87T-A，87T’-A，87T-B，87T’-B)作为主变压器内部及引出线短路故障的主保护。保护装置应能满足多端CT接入要求。其中87T’-A和87T’-B保护范围包含换相开关、被拖动开关Q91和拖动开关Q92及其相关母线，在同步拖动和被拖动过程中退出。保护瞬时动作于断开主变压器各侧断路器并停机。保护配置方案见图2所示。

图2 双冗余发变组继电保护配置图

增加保护冗余度方案的优点：使用1套保护装置硬件设备和使用三组电流互感器，通过软件编程，可组成大差、小差2套保护，相互切换。正常运行时大差保护，在同步拖动和被拖动过程中退出大差，投入小差，保证发电机、变压器等设备始终具有2套主保护。

该方案的缺点是增加了保护装置运行软件的开销，还需要在发电机主引出母线上增加4套电流互感器（12只）及其引出电缆，不但增加建设投资，而且增加了外部接线的复杂性。

2）改变微机差动保护的运算条件，控制差动保护装置的保护范围

微机型主变继电保护装置一般采用多端电流输入。每端输入电流的极性、相位、量程等都可通过软件编程实现灵活控制，还可以通过外接开关量闭锁各端输入电流不参与保护运算（西门子电气公司7UT635差动保护就具备此功能）。据此，我们可以分析抽水蓄能机组的2种运行工况：

当机组处于被拖动工况时，其GCB处于分闸状态；当机组处于拖动工况时，其换相开关处于分断状态。在上述2种工况下，发电电动机与主变低压侧处于分断状态，对于主变压器4端电流差动保护，发电电动机母线支路CT电流应该为0，发电电动机侧CT电流不参与主变差动回路的电流运算，主变压器4端电流差动保护变为3端电流差动，主变差动高压侧电流、SFC支路电流及高厂变支路电流仍然构成完整差动保护，不影响变压器继电保护功能，整套保护不需退出，保护范围由发电机支路CT处退到断路器（或换相开关）的上断口。

该方案优点是接线简单，保护范围不受小差CT位置的影响，从图3可见，励磁变、换相开关及主变低压侧电压互感器等均不会退出，保护范围大。蒲石河抽水蓄能电站安装调试期间，已按上述方案对主变大差保护进行了修改，运行情况良好。

图3 优化的发变组纵差动继电保护配置图

总结蒲石河工程经验，抽水蓄能电站发变组纵差动保护的优化配置方案如图3所示。主变差动保护配置2组大差，发电机差动保护配置2组小差，发电机差动保护与主变差动保护的两组电流互感器在发电机出口与短路开关区间重叠配置。发电机差动保护可运行于任何工况，不必加闭锁条件；主变两组差动保护采用支路电流投/退控制方式，当保护运行于拖动工况、被拖动工况或电制动工况时，用保护外部形成的工况控制条件（见图1），将主变保护装置发电机支路CT电流退出，改变主变差动保护的保护范围，保证主变保护的正常运行。

［1］NB/T35010-3013，水力发电厂继电保护设计规范［S］.

［2］郑光伟，张全胜，牛聚山，等.蒲石河抽水蓄能电站电气二次设计［J］.水力发电，2012（5）.

［3］姜树德.抽水蓄能电站电气二次设备和接线特点［J］.电力设备，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