GB/T 45119-2024 Technical requirement for insulation monitoring of low voltage power system in power plants and substations
1 Scope
This document specifies the basic requirements, monitoring requirements, installation acceptance, operation and maintenance requirements for insulation monitoring of low voltage power system in power plants and substations.
This document is applicable to the design, selection, installation and use of insulation monitoring of low voltage AC and DC power systems in power projects such as power plants, substations and converter stations.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 2423.1-2008 Environmental testing for electric and electronic products - Part 2: Test methods - Tests A: Cold
GB/T 2423.2-2008 Environmental testing for electric and electronic products - Part 2: Test methods - Tests B: Dry heat
GB/T 2423.5-2019 Environmental testing - Part 2: Test methods - Test Ea and guidance: Shock
GB/T 2423.10-2019 Environmental testing - Part 2: Test methods - Test Fc: Vibration (sinusoidal)
GB/T 2900.1 Electrotechnical terminology - Fundamental terms
GB/T 2900.33 Electrotechnical terminology - Power electronics
GB/T 17626.2 Electromagnetic compatibility - Testing and measurement techniques - Electrostatic discharge immunity test
GB/T 17626.3 Electromagnetic compatibility - Testing and measurement techniques - Part 3: Radiated, radio-frequency, electromagnetic field immunity test
GB/T 17626.4 Electromagnetic compatibility - Testing and measurement techniques - Electrical fast transient/burst immunity test
GB/T 17626.5 Electromagnetic compatibility - Testing and measurement techniques - Surge immunity test
GB/T 17626.6 Electromagnetic compatibility - Testing and measurement techniques - Immunity to conducted disturbances, induced by radio-frequency fields
GB/T 17626.8 Electromagnetic compatibility - Testing and measurement techniques - Power frequency magnetic field immunity test
GB/T 17626.10 Electromagnetic compatibility - Testing and measurement techniques - Damped oscillatory magnetic field immunity test
GB/T 17626.18 Electromagnetic compatibility - Testing and measurement techniques - Damped oscillatory wave immunity test
DL/T 860 (All parts) Communication networks and system for power utility automation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.1, GB/T 2900.33 and GB/T 4365 and the following apply.
3.1
insulation monitoring
monitoring and measuring the insulation condition of low voltage AC and DC power supply system bus and branch circuit to ground
3.2
grounding resistance
insulation resistance to ground of bus or branch of AC and DC power system with ungrounded operation mode
3.3
balancing bridge
(Wheatstone) detection bridge composed of positive and negative equivalent artificial grounding resistance and DC bus grounding resistance. When the bus insulation is good or the resistance value of the grounding resistance is similar, the detection bridge is in balanced state
3.4
unbalanced bridge
invention relates to a bridge composed of (alternately) switched positive and negative artificial grounding resistors, and forms a detection bridge with a balance bridge resistance
3.5
signal injection method
method of inputting known AC, DC, square wave pulse and adaptive pulse signals into the branch, monitoring the corresponding grounding fault signal, detecting the grounding branch or locating the grounding point
4 Basic requirements
4.1 Working environment
Normal working environment of insulation monitoring equipment (hereinafter referred to as "insulation monitoring equipment") of low voltage AC and DC power systems in power plants:
a) The ambient temperature is -5°C~+40°C;
b) The daily average relative humidity shall not exceed 95%, the monthly average relative humidity shall not exceed 90%, and there is no condensation;
c) The altitude is not exceeding 2,000 m;
d) Good ventilation, no explosion hazard, no corrosive gas, and no mold;
e) There is no violent vibration source, no strong electromagnetic interference, and the external magnetic field induction intensity does not exceed 0.5 mT;
f) The horizontal acceleration of vibration does not exceed 0.3 g and the vertical acceleration does not exceed 0.15 g.
Note: Special environmental conditions shall be considered when formulating relevant standards for insulation monitoring equipment.
4.2 Electrical performance
4.2.1 Working power supply
4.2.1.1 The working power supply of insulation monitoring equipment shall be connected from the busbar through the protective appliance. DC input power supply shall be used when monitoring DC system; when monitoring the AC system, AC input power supply or DC input power supply shall be used, and AC and DC power supply shall not be input at the same time.
4.2.1.2 The DC input power supply shall work normally within the following ranges:
a) The voltage range of the 220 V power supply is 176 V~286 V;
b) The voltage range of the 110 V power supply is 88 V~143 V;
c) Ripple coefficient ≤ 5%.
4.2.1.3 The AC input power supply shall work normally within the following ranges:
a) The voltage range of the 380 V power supply is 304 V~456 V;
b) The voltage range of the 220 V power supply is 176 V~264 V;
c) The frequency range is 47.5 Hz~52.5 Hz;
d) The voltage is a sine wave, and the total harmonic content does not exceed 10%.
4.2.2 Dielectric capability
The electrical insulation performance of the following parts of the insulation monitoring equipment shall not be lower than the requirements in Table 1:
a) Between non-electrically connected live circuits;
b) Between each independent live circuit and the ground (metal frame);
c) Between the communication interface and the ground (metal shell of the chassis).
Contents Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Basic requirements 4.1 Working environment 4.2 Electrical performance 4.3 Communication and others 5 Test requirements 5.1 Classification 5.2 Functional indexes 5.3 Main way 6 Installation acceptance 6.1 Inspection 6.2 Arrangement 6.3 Acceptance 7 Operation and maintenance 7.1 Operation 7.2 Maintenance Annex A (Normative) Environmental adaptability and electromagnetic compatibility requirements Annex B (Informative) Insulation monitoring of low voltage DC ungrounded systems Annex C (Informative) Insulation monitoring of low voltage AC ungrounded systems Annex D (Informative) Insulation monitoring of low voltage AC grounding systems Bibliography
电力厂站低压用电系统的绝缘监测技术要求 1范围 本文件规定了电力厂站低压用电系统的绝缘监测的基本要求、监测要求、安装验收和运行维护等要求。 本文件适用于发电厂、变电站、换流站等电力工程低压交直流用电系统绝缘监测的设计、选型、安装和使用。 2规范性引用文件 下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。其中,注日期的引用文件,仅该日期对应的版本适用于本文件;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 2423.1-2008 电工电子产品环境试验 第2部分:试验方法试验A：低温 GB /T 2423.2-2008 电工电子产品环境试验 第2部分: 试验方法 试验B:高温 GB/T 2423.5-2019 环境试验 第2部分: 试验方法 试验Ea和导则: 冲击 GB/T 2423.10-2019 环境试验 第 2 部分: 试验方法 试验Fc : 振动(正弦) GB/T 2900.1 电工术语 基本术语 GB/T 2900.33 电工术语 电力电子技术 GB / T4365 电工术语 电磁兼容 GB / T 17626.2 电磁兼容 试验和测量技术 静电放电抗扰度试验 GB / T 17626.3 电磁兼容 试验和测量技术 第 3 部分: 射频电磁场辐射抗扰度试验 GB / T 17626.4 电磁兼容 试验和测量技术 电快速瞬变脉冲群抗扰度试验 GB / T 17626.5 电磁兼容 试验和测量技术 浪涌(冲击)抗扰度试验 GB / T 17626.6 电磁兼容 试验和测量技术 射频场感应的传导骚扰抗扰度 GB / T 17626.8 电磁兼容 试验和测量技术 工频磁场抗扰度试验 GB / T 17626.10 电磁兼容 试验和测量技术 阻尼振荡磁场抗扰度试验 GB / T 17626.18 电磁兼容 试验和测量技术 阻尼振荡波抗扰度试验 DL / T860 (所有部分) 电力自 动化通信网络和系统 3术语和定义 GB / T2900.1、 GB / T2900.33、 GB / T4365 界定的以及下列术语和定义适用于本文件。 3.1 绝缘监测 insulation monitoring 监视及测量低压交、直流电源系统母线和支路对地绝缘状况。 3.2 接地电阻grounding resistance 采用不接地运行方式的交、直流电源系统母线或支路的对地绝缘电阻。 3.3 平衡桥balancing bridge 一种 正、负极等值人工接地电阻与直流母线接地电阻构成的(惠斯通)检测电桥, 在母线绝缘良好或接地电阻阻值相近时检测电桥处于平衡状态。 3.4不平衡桥unbalanced bridge 一种由(交替)投切的正、负极等值人工接地电阻构成的电桥, 并与平衡桥电阻构成检测电桥。 3.5 信号注入法 signal injection method 用已知交流、直流、方波脉冲以 及自 适应脉冲的信号输入在支路中, 监测对应产生的接地故障信号, 侦测接地支路或定位接地点的方法。 4基本要求 4.1工作环境 电力厂站低压交直流用电系统绝缘监测设备(以下简称“绝缘监测设备”)的正常工作环境: a )环境温度为 -5 ℃ ~+40 ℃ ; b ) 日平均相对湿度不超过 95% , 月 平均相对湿度不超过 90% , 无凝露; c )海拔不超过 2 000 m ; d )通风良好, 无爆炸危险, 无腐蚀性气体, 无霉菌; e )无剧烈振动源, 无强电磁干扰, 外磁场感应强度不超过 0.5 mT ; f )振动水平加速度不超过 0.3 g , 垂直加速度不超过 0.15 g 。 注: 特殊环境条件在制定相关绝缘监测设备标准时考虑。 4.2电气性能 4.2.1工作电源 4.2.1.1绝缘监测设备的工作电源应从母线上经过保护电器引 接。 用于监测直流系统时应采用直流输入电源; 监测交流系统时应采用交流输入电源或直流输入电源, 不应采用交直流电源同时输入。 4.2.1.2直流输入电源应在以下范围内正常工作: a)220 V 电源电压范围为 176 V~286 V ; b) 110 V 电源电压范围为 88 V~143 V ; c)纹波系数 ≤5% 。 4.2.1.3交流输入电源应在以下范围内正常工作: a )380 V 电源电压范围为 304 V~456 V ; b ) 220 V 电源电压范围为 176 V~264 V ; c )频率范围为 47.5 Hz~52.5 Hz ; d )电压为正弦波, 总谐波含量不超过 10% 。 4.2.2绝缘性能 绝缘监测设备的下列部位的电气绝缘性能应不低于表 1 的要求: a )非电连接的各带电电路之间; b )各独立带电电路与地(金属框架)之间; c )通信接口 对地(机箱金属外壳)之间。
