Direct current de-icing devices—Part 2: Thyristor valves
1 Scope
This part of GB/T 31487 specifies the basic requirements for the function, design and test of thyristor valves of DC de-icing devices.
This part is applicable to water cooling thyristor valves of DC de-icing devices. It may also serve as a reference for thyristor valves adopting other cooling methods.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3859.1-2013 Semiconductor converters - General requirements and line commutated converters - Part 1-1: Specification of basic requirements
GB/T 13498 Terminology for high-voltage direct current (HVDC) transmission
GB/T 16927.1 High-voltage test techniques - Part 1: General definitions and test requirements
GB/T 20990.1-2007 Thyristor valves for high voltage direct current (HVDC) power transmission - Part 1: Electrical testing
GB 50150-2006 Standard for hand-over test of electric equipment electric equipment installation engineering
IEC/TS 60815-1: 2008 Selection dimensioning of high-voltage insulators intended fuse in polluted conditions - Part 1: Definitions, information general principles
IEC 61803: 2011 Determination of power losses in high-voltage direct current (HVDC) converter stations with line-commutated converters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 13498 and the following apply.
3.1
valve
electrical and mechanical combination composed of power electronic devices and auxiliary components, which can realize unidirectional or bidirectional conduction
Note: At present, the commonly used valves include diode valves, thyristor valves, insulated-gate bipolar transistors (IGBT), etc.
3.2
thyristor valve
valve whose power electronic devices are thyristor valves
3.3
converter
electrical device capable of realizing complete commutation function
3.4
single valve
valve composed of several thyristor levels in series, which is an arm of 6-pulse converter
3.5
thyristor level
component of a valve, which consists of a thyristor or several parallel thyristors and auxiliary equipment adjacent to them
3.6
valve electronics
electronic circuit that performs control, monitoring and protection functions at valve potential
3.7
valve base electronics
electronic equipment that provides an interface between a ground potential control equipment and valve electronics or valve device, also known as a valve interface electronic equipment
3.8
firing angle
time from the forward zero crossing of the ideal sinusoidal commutation voltage to the beginning of the forward current conduction, measured from an electrical angle
3.9
rated direct current
direct current (average value) output by the converter according to the specified load conditions and service conditions
3.10
maximum direct current
maximum direct current output by the converter to the load under specified operating conditions (theoretically within an infinite time)
Note: Generally, there are different values under different cooling media and ambient temperature.
3.11
2h overload direct current
direct current that the converter can output to the load within the specified 2h
Note: Generally, there are different values under different cooling media and ambient temperature.
3.12
maximum ideal no-load direct voltage
maximum direct voltage (Udi0max) of the converter under no-load condition
Note: At this time, all kinds of voltage drops and grid voltage fluctuation factors are ignored.
3.13
rated direct voltage
average value that the direct voltage output by converter shall reach under the specified conditions
3.14
rated direct power
product of rated direct voltage and rated direct current of converter
3.15
coefficient of current distribution
ratio of the average value of branch current in parallel operation to the maximum branch current value when the thyristor valve of DC de-icing device adopts double-bridge parallel connection type
3.16
rated junction temperature
maximum junction temperature allowed for normal operation of thyristor
3.17
large angle and high current operation
operation mode in which DC de-icing device outputs rated direct current output and the firing angle is approximately 90°
3.18
zero power test
test for inspecting the direct current control function and current withstand capacity of the DC de-icing device, in which the direct current side of the DC de-icing device is short-circuited through a reactor and the direct current is increased to the set value
4 Technical requirements
4.1 Environmental conditions
The normal use environment conditions of thyristor valve of DC de-icing device include the following aspects:
a) the altitude is less than 2,000m;
b) the ambient temperature is not less than -20°C and not higher than 50°C;
c) the maximum relative humidity is 85% (below 20°C);
d) the pollution grade is b;
e) the magnitude of the earthquake is not more than Grade 8;
f) the frequency fluctuation range of AC power grid shall not exceed ±5%.
Note 1: When the altitude is greater than 2,000m, the altitude correction design shall be carried out according to relevant standards.
Note 2: The outdoor pollution grades are designed generally according to Grade d in IEC/TS 60815-1: 2008.
4.2 Access system
The converter of DC de-icing device should be connected to the low voltage side (10kV or 35kV) of the main transformer meeting the de-icing capacity requirements through special converter transformer or commutation reactor, or directly connected to the low voltage side of the main transformer. Otherwise, it shall be connected to the upper power bus through a special transformer.
4.3 Load properties
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
4.1 Environmental conditions
4.2 Access system
4.3 Load properties
4.4 Functional requirements
5 Electrical connection type of thyristor valve
6 Design of thyristor valve
6.1 Electrical design of thyristor valve
6.2 Mechanical design of thyristor valve
6.3 Thermal design of thyristor valve
7 Tests
7.1 Introduction
7.2 Type test and routine test
7.3 Field test
Annex A (Normative) Loss calculation method of thyristor valve
直流融冰装置 第2部分：晶闸管阀
1 范围
GB/T 31487的本部分规定了直流融冰装置晶闸管阀的功能、设计和试验等的基本要求。
本部分适用于直流融冰装置水冷却晶闸管阀，采用其他冷却方式的晶闸管阀可参照本部分。
2 规范性引用文件
下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。
GB/T 3859.1—2013 半导体变流器 通用要求和电网换相变流器 第1-1部分：基本要求规范
GB/T 13498 高压直流输电术语
GB/T 16927.1 高压试验技术 第1部分：一般定义及试验要求
GB/T 20990.1—2007高压直流输电晶闸管阀 第1部分：电气试验
GB 50150—2006 电气装置安装工程 电气设备交接试验标准
IEC/TS 60815-1：2008 污染环境中所用高压绝缘子的选择和尺寸测定 第1部分：定义、信息和一般原理(Selection dimensioning of high-voltage insulators intended fuse in polluted conditions—Part 1：Definitions，information general principles)
IEC 61803：2011 采用电网换相换流器的高压直流(HVDC)换流站功率损耗的确定[Determination of power losses in high-voltage direct current (HVDC) converter stations with line-commutated converters]
3 术语和定义
GB/T 13498界定的以及下列术语和定义适用于本文件。
3.1
阀 valve
由电力电子器件及辅助部件组成的电气和机械联合体，能实现单向或者双向导通。
注：目前常用的阀有二极管阀、晶闸管阀、绝缘栅双极晶体管(IGBT)阀等。
3.2
晶闸管阀 thyristor valve
电力电子器件为晶闸管的阀。
3.3
换流器 converter
能实现完整换流功能的电气装置。
3.4
单阀 single valve
由若干个晶闸管级串联组成，是6脉波换流器的一个臂。
3.5
晶闸管级 thyristor level
阀的部件，由一个晶闸管或若干并联的晶闸管与紧靠它们的辅助设备构成。
3.6
阀电子电路 valve electronics
在阀电位上执行控制、监测和保护功能的电子电路。
3.7
阀基电子单元 valve base electronics
提供地电位控制设备与阀电子电路或阀装置之间接口的电子设备，又称阀接口电子设备。
3.8
触发角 firing angle
从理想正弦换相电压正向过零点至正向电流导通开始时刻的时间，以电角度度量。
3.9
额定直流电流 rated direct current
按规定的负载条件和使用条件，换流器输出的直流电流(平均值)。
3.10
最大直流电流 maximum direct current
换流器在规定的运行条件下，(理论上可在无限时间内)向负载输出的最大直流电流。
注：一般在不同冷却媒质和环境温度下有不同值。
3.11
2h过载直流电流 2h overload direct current
换流器在规定的2h内，能向负载输出的直流电流。
注：一般在不同冷却媒质和环境温度下有不同值。
3.12
最大理想空载直流电压 maximum ideal no-load direct voltage
一般指换流器在空载情况下的最大直流电压(Udi0max)。
注：此时，将各种电压降和电网电压波动的因素忽略不计。
3.13
额定直流电压 rated direct voltage
在规定条件下，换流器输出的直流电压应达到的平均值。
3.14
额定直流功率 rated direct power
换流器额定直流电压与额定直流电流之积。
3.15
均流系数 coefficient of current distribution
直流融冰装置晶闸管阀采用双桥并联型式时，并联运行支路电流的平均值与最大支路电流值之比。
3.16
额定结温 rated junction temperature
晶闸管正常工作允许的最高结温。
3.17
大角度大电流运行 large angle and high current operation
直流融冰装置输出额定直流电流且触发角近似90°的运行方式。
3.18
零功率试验 zero power test
直流融冰装置直流侧经电抗器短接，将直流电流升至设定值，检查直流融冰装置直流电流控制功能及电流承受能力。
4 技术要求
4.1 环境条件
直流融冰装置晶闸管阀正常使用环境条件包括以下方面：
a)海拔小于2000m；
b)环境温度不低于－20℃，不高于50℃；
c)相对湿度最大值为85％(20℃以下时)；
d)污秽等级为b级；
e)地震震级，不超过8级；
f)交流电网频率波动范围不超过±5％。
注1：当海拔高度大于2000m时，应根据相关标准进行海拔修正设计。
注2：户外污秽等级，在设计时，一般按照IEC/TS 60815-1：2008中的d级考虑。
4.2 接入系统
直流融冰装置换流器宜通过专用换流变压器或者换相电抗器接在满足融冰容量要求的主变压器低压侧(10kV或35kV侧)，也可与主变压器低压侧直接连接。否则，应通过专用变压器接在上一级电源母线上。
4.3 负载性质
直流融冰装置换流器的负载，主要是不同规格和不同长度的架空导线、架空地线、光纤复合地线(OPGW)、电抗器及其组合。
对直流融冰兼静止无功补偿装置换流器，在静止无功补偿模式下为三相交流电压控制电路，负载为电抗器。
4.4 功能要求
4.4.1 输出直流电流的范围
直流融冰装置换流器输出的直流电流，在稳定运行时，允许选择从设计要求最小值到最大电流之间的任意电流值。
4.4.2 输出直流电流的偏差
直流融冰装置换流器输出的直流电流，在稳定运行时，其输出电流的偏差应在目标设定值的±5％以内。
4.4.3 输出直流电压的要求
直流融冰装置换流器输出的直流电压应满足设计要求。
4.4.4 输出电流的断续要求
在电流较小的情况下，直流融冰装置晶闸管阀的输出电流可能出现断续的情况。如果每周波电流断续的次数少于6次，晶闸管阀应能短时间运行(至少10min)。一般情况下应加装平波电抗器以保证零功率试验和架空地线(或光纤复合地线OPGW)融冰等工况下的电流连续。
4.4.5 大角度大电流运行的要求
直流融冰装置晶闸管阀应允许在大电流大角度方式下持续稳定运行。在输出直流电流达到额定电流，触发角度近似90°的工况下，连续运行时间大于2h。
4.4.6 工作于静止无功补偿模式的要求
对直流融冰兼静止无功补偿装置，晶闸管阀需要满足直流融冰和静止无功补偿两种运行模式的要求。
5 晶闸管阀的电气联结型式
直流融冰装置晶闸管阀的电气联结型式为6脉波换流器或12脉波换流器。12脉波换流器由两组6脉波换流器串联或者并联组成。6脉波换流器每相的臂称为单阀。
为了满足电能质量的要求，减少直流融冰装置运行对供电系统的影响，在将两组6脉波换流器串联或并联时，阀侧绕组间的相位(角)差应为30°，以构成12脉波换流器。
6脉波换流器如图1所示，两组6脉波换流器串联构成的12脉波换流器如图2a)所示，两组6脉波换流器并联构成的12脉波换流器如图2b)所示。
