DNV-电压总畸变率消除稳定器
 

• 电压总畸变率的概念
  1. 电压总畸变率国标要求，根据国标GB/T 14549-93《 电能质量 公用电网谐波》

母线电压公用电网谐波电压(相电压)限值

电网标称电压KV	电压总谐波畸变率%	各次谐波电压含有率,%
		奇 次	偶 次
0.38KV	5.0	4.0	2.0
6KV	4.0	3.2	1.6
10KV
35KV	3.0	2.4	1.2
66KV
110KV	2.0	1.6	0.8

 

1. 2. 什么是电压波形总畸变率

电压波形畸变率又称总谐波失真率，是用来衡量电力系统电压谐波含量的一项重要指标。它反映了负载对电网谐波污染的严重程度以及电力设备对电网中谐波的发出情况。

1. 3. 电压波形总畸变率的计算方法

电压波形畸变率通常用 THDu 表示，计算公式为:
THDu=((∑Un)/Un)1/2x100%
其中，Un是电压的基波值，Un是电压基波的有效值，∑Un是所有谐波电压的平方和。

1. 4. 电压总畸变率过高的由来
2. 、负载设备谐波电流过大，各次的谐波电压过高叠加造成总电压谐波畸变过高。
3. 、背景谐波电压，供电电网并网不同高次的谐波电压，电压等电位反馈到低压侧引起的供电背景电压畸变率过高。
4. 、光伏，风力，储能等不同的新能源发电并网，并网电压不稳引起的电压拉扯引起电压波形畸形的电压波动引起电压畸变率过高。

• 电压总畸变率过高的危害

2.1、 电压总畸变率过高对变压器危害，引起变压器噪音变大，铁心尖叫声较大，铁损，线损增加。严重会引起磁通量变大，变压器严重过热烧毁 。
2.2、 电压总畸变率过高对配电开关线圈及保护危害，会引起电压击穿二次操作线圈，会引保护仪表电路板电压击穿，烧坏电子电路元件 。
2.3、 电压总畸变率过高对仪器仪表危害，会直接电压击穿烧坏仪器仪表的电源模块 。
2.4、 电压总畸变率过高对电动机的危害，会引起电机励磁改变，电压击穿电动机线圈绝缘，烧坏电动机 。

• 电压总畸变率过高处理选择方案

  3.1、 很多行业对电压畸变率过高都是以为谐波电流引起，只要治理谐波电流就能降低电压畸变，针对是负载侧引起的电压畸变过高确实可以治理谐波后，电压总畸变率确实能下降达到国标要求。
3.2、 现今电力电子发展已经发生质的变化，大部分负载设备都已经配套电子滤波功能，由于电子滤波的特性只能消除各次的谐波电流同时引起反馈到电网侧的各次电压谐波值变大，由于不同的次数谐波电压相互叠加在电网中引起了电压总畸变率变高 。
3.3、 很多电力电子应该用的现场都反馈一个问题，谐波电流不高的条件谐波电压比例较高，电压总畸变率达到6%-30%不等。经常引起负载设备电子烧坏或故障报警。
3.4、 针对不同的电压总畸变率过高的问题，励特电能专门开发出一种新型电压总畸变率消除稳定器，DNV-电压总畸变率消除稳定器是一款针对不同电压谐波的消除补偿。可以为负载电压总畸变率消除也可以为电网侧电压总畸变率消除 。

• DNV-产品应用

1. 半导体行业（芯片制造，测试和封装）
2. 新能源行业（太阳能多晶硅，单晶硅拉硅，电池测试，老化及封装等）
3. 医疗器械行业（医疗检测仪器，放射化疗仪器，液相分析仪等等）
4. 汽车制造行业（自动焊接，涂装，油漆烘烤等等）
5. 食品饮料行业（食品烘焙，包装，罐装，制瓶机等等）
6. 石油化工行业（加油机，炼油机，磕头机，化工厂等等）
7. 纺织行业（丝印机，缠绕机，卷扬机等等）

• DNV-产品原理
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• DNV-产品接线图

DNV Voltage Total Distortion Elimination Stabilizer
 

• The concept of total voltage distortion rate
  1. According to the national standard requirements for total voltage distortion rate, according to the national standardGB/T 14549-93Harmonics in Power Quality Public Grid

Limit values for harmonic voltage (phase voltage) of bus voltage in public power grid

The nominal voltage of the power grid is KV	Voltage total harmonic distortion rate%	Content of each harmonic voltage,%
		Qi Ci	My times
0.38KV	5.0	4.0	2.0
6KV	4.0	3.2	1.6
10KV
35KV	3.0	2.4	1.2
66KV
110KV	2.0	1.6	0.8

 

1. 2. What is the total distortion rate of voltage waveform

Voltage waveform distortion rate, also known as total harmonic distortion rate, is an important indicator used to measure the harmonic content of voltage in power systems. It reflects the severity of harmonic pollution caused by loads on the power grid and the emission of harmonics in the power grid by power equipment.

1. 3. Calculation method for total distortion rate of voltage waveform

The voltage waveform distortion rate is usually represented by THDu, and the calculation formula is:
THDu=((∑Un)/Un)1/2x100%
Among them, Un is the fundamental value of the voltage, Un is the effective value of the fundamental voltage, and ∑ Un is the sum of squares of all harmonic voltages.

1. 4. The origin of high total voltage distortion rate
2. The harmonic current of the load equipment is too high, and the superposition of each harmonic voltage is too high, resulting in excessive distortion of the total voltage harmonics.
3. Background harmonic voltage, harmonic voltage of different orders of power grid connection, and high distortion rate of power supply background voltage caused by voltage equipotential feedback to the low voltage side.
4. Different new energy sources such as photovoltaics, wind power, and energy storage are connected to the grid. The unstable grid voltage causes voltage pulling, resulting in abnormal voltage waveforms and high voltage distortion rates.

• The harm of high total voltage distortion rate

2.1. High total voltage distortion rate poses a threat to transformers, causing increased transformer noise, loud iron core screams, and increased iron and line losses. Severe cases can cause an increase in magnetic flux, leading to severe overheating and burnout of transformers.
2.2. Excessive total voltage distortion rate poses a risk to the distribution switch coil and protection, causing voltage breakdown in the secondary operation coil and triggering voltage breakdown in the protective instrument circuit board, which can burn out electronic circuit components.
2.3. Excessive total voltage distortion rate poses a threat to instruments and can directly cause voltage breakdown and burn out the power module of the instrument.
2.4. The harm of high total voltage distortion rate to electric motors can cause changes in motor excitation, voltage breakdown of motor coil insulation, and burning of the motor.

• Selection scheme for handling high total voltage distortion rate

3.1 Many industries believe that high voltage distortion rates are caused by harmonic currents. As long as harmonic currents are controlled, voltage distortion can be reduced. For voltage distortions caused by the load side, it is indeed possible to control harmonics and reduce the total voltage distortion rate to meet national standards.
3.2. The development of power electronics has undergone a qualitative change, and most load devices are now equipped with electronic filtering functions. Due to the characteristics of electronic filtering, it can only eliminate harmonic currents of various orders and cause an increase in the harmonic values of various voltages fed back to the grid side. The superposition of different harmonic voltages in the grid has led to an increase in the total voltage distortion rate.
3.3. Many on-site applications of power electronics have reported a problem where the proportion of harmonic voltage is relatively high under conditions of low harmonic current, and the total voltage distortion rate ranges from 6% to 30%. Often causing electronic burnout or malfunction alarms in load devices.
3.4 In response to the problem of high total voltage distortion rates, Lite Electric has developed a new type of voltage total distortion rate elimination stabilizer. DNV voltage total distortion rate elimination stabilizer is a compensation tool designed to eliminate different voltage harmonics. It can eliminate the total distortion rate of load voltage or the total distortion rate of grid side voltage.

• DNV - Product Application

1. Semiconductor industry (chip manufacturing, testing, and packaging)
2. New energy industry (solar polycrystalline silicon, monocrystalline silicon pulling silicon, battery testing, aging and packaging, etc.)
3. Medical device industry (medical testing equipment, radiotherapy and chemotherapy equipment, liquid phase analyzer, etc.)
4. Automotive manufacturing industry (automatic welding, painting, paint baking, etc.)
5. Food and beverage industry (food baking, packaging, canning, bottle making machines, etc.)
6. Petrochemical industry (refueling machines, refineries, kowtow machines, chemical plants, etc.)
7. Textile industry (screen printing machines, winding machines, winches, etc.)

• DNV - Product Principle
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• DNV - Product Wiring Diagram