由數據採集專家 Grant Maloy Smith 撰寫

在本文中,我们将研究什么是功率分析以及用于执行功率分析的工具。 在本文中,您将:

  • 看看真正的电力是什么
  • 了解我们为什么需要功率分析以及如何进行功率分析
  • 了解如何进行功率分析以及什么是功率分析仪。

你准备好开始了吗? 我们走吧!

什么是功率分析?

功率是完成工作的速率,即每单位时间消耗的能量。 电气系统的功率是电压与电流的乘积,经过积分后再除以周期性时间。 为了计算电气系统的功率,必须知道周期时间(等于频率)。 “功率分析”是简单的测试和研究功率的方法,通常使用功率分析仪。

什么是功率分析仪?

功率分析仪是一种用于测量和量化电气系统中功率流率的仪器。 潮流以焦耳/秒(J / s)或千瓦时(kW / h)表示。 电能是在两点之间在电气系统中传输的每单位时间的速率。电能在两点之间在电气系统中传输的每单位时间的速率。

SIRIUS XHS Power AnalyzerSIRIUS XHS功率分析仪具有4路高压和4路低压放大器,用于电流传感器连接

什么是电力

您可以看一下电路,但是看不到是否存在电压或是否有电流在流动。 您绝对不能伸出手去寻找,因为这是极其危险的,甚至可能是致命的。 因此,我们必须使用正确的仪器来测量电。

那么我们如何可视化通过电路的电流呢? 好吧,我们可以看到水在运动,所以让我们用它作为一个类比来解释电路是如何工作的。 众所周知的事实是,如果水要从管道中流出,则水需要有力或“压力”通过重力或机械泵将其推动。

电路图与水泵的比较

以我们的类比:

  • 电压是迫使水通过管道的压力。 压力越高,水将流动得越快。 以伏特(V)为单位。
  • 电流是水流入的可用体积。体积越大,水可以流入的越多。 单位为安培(A)。
  • 电阻是管道内部体积的减少,从而限制了水的流动。 单位为欧姆(R或Ω)。

如果电流仅在一个方向上移动,则非常像水流过管道或软管。 在我们的类比中,这是 DC(直流电 。但是,如果电流来回移动,则类似于AC(交流电)

交流电是我们用于从电厂到家庭和企业的长距离运输的工具。

直流电用于现代电子产品以及电池。

例如,您可能正在阅读的办公计算机已插入交流电源,但内部有一种类型的变压器,称为开关模式电源(SMPS),可将交流电转换为直流电并将直流电压转换为所需的电压 等级。 如果您使用的是笔记本电脑,则SMPS可能位于外部“砖”中,该砖连接在墙壁上的交流电源插座和笔记本电脑内部的直流电源系统之间。 如果您是在手机或平板电脑上阅读此书,那它也是使用外部SMPS为其内部电池充电的DC设备。

量化电力

在物理学中,电力是做功的速率。 它等于每单位时间消耗的能量。 功率单位为每秒焦耳(J / s),也称为 瓦特(W)

什么是电力?

电能 是电能在两点之间在电气系统中传输的每单位时间的速率。 热力学第一定律指出,不能产生或破坏能量。 它只能从一种能量转换为另一种能量,也可以转移。

由于不存在理想的电气系统,因此在进行能量传输时总会有一些损耗。 电气系统中最常见的损耗形式是热量。 如果电路在物理上是热的,则意味着电路所携带的某些能量已转换为热量,因此无法用于做有用的工作。

这降低了整个电气系统的效率。 机械系统也会产生热量,这不是巧合-请勿将手放在发光的白炽灯泡上,否则您将直接体验到能量转化为热能的过程。 一般而言,电力只是电力基本物理学的延伸。

常规地,电力以千瓦(kW)表示。

我们如何计算电功率?

电路中的电量是通过将电压(V)乘以电流(A)得出瓦特(W)来计算的,使用以下公式:

\[P(t) = I(t) \cdot V(t)\]

可以使用欧姆定律对这个基本方程式进行变换,该定律指出在恒定温度下,流经线性电阻的电流与电压成正比,与电路的电阻成反比。 欧姆定律可以通过以下几种方式写成:

\[V = I \cdot R\]

\[P = V \cdot I\]

\[P = I^2 \cdot R\]

\[P = \frac{V^2} {R}\]

但是欧姆定律仅适用于 直流电(DC),在直流电中电压和电流的流量是恒定的。

但是使用 交流电(AC)时,欧姆定律方程式只会在某一时刻产生功率。 因此,我们需要一种不同的交流测量方法。

如果要分析其特性,我们需要一个方程来准确描述电功率。 幸运的是,有一个等式:

\[P=\frac{1}{T}\int_{t=0}^T u(t)\cdot i(t)\;dt\]

这里:

  • P 是瓦特(W),功率
  • i i是电流,安培(A)
  • u 是电压,伏特(V)
  • T 是周期时间(以秒为单位)

让我们在图形上形象地看这个等式:

Power calculation equation visualized on a cartesian plane showing the voltage and current, and the resulting power curve after integration
在笛卡尔坐标系可视化的功率计算方程式,显示了电压和电流,以及积分后所得的功率曲线。

在可视化图中查看波形的曲率,我们可以看到,交流系统中的功率不仅仅是直流系统中的电压乘以电流。 它由一个周期内瞬时功率的时间平均值定义。 这意味着我们必须知道频率才能计算电气系统的功率。

了解功率测量

原则上,要测量的交流(AC)电气系统中有三种类型的电源。 这些都是:

  1. 有功功率(P)
  2. 无功功率(Q)
  3. 视在功率(S)

为了说明它们之间的关系,有一个方便的工具,我们可以根据勾股定理使用称为幂三角的工具:

Power triangle, illustrating the relationship between active, reactive, and apparent power, including the angle phi and the power factor, also known as cosine phi (cos phi)功率三角形,说明有功,无功和视在功率之间的关系,包括角度phi和功率因数,也称为余弦角(cos phi)

让我们更深入地了解这些术语及其真正含义:

什么是有功功率(P)

有功功率(P) 也称为“有功功率”或“有功功率”是交流电路内使用的有用功率。

什么是无功功率(Q)

无功功率(Q)不使用,而是在电源(例如电站)和负载之间传输的,它主要用于通过电气系统传输有功功率。

什么是视在功率(S)

视在功率(S) 是交流电源系统中有功功率和无功功率的矢量和。

什么是功率因数(PF)

功率因数(PF)是有功功率与无功功率之间的比率,取值范围为1到-1。

功率因数表示与组合有功功率和无功功率的视在功率相比,传输线中存在的有功功率量。换句话说,它是传输线中的有用功率小于理论上可能的最大功率的量。理论上理想的功率因数降低是由电压和电流异相引起的。

功率因数通常表示为“ cos phi”,“ cosine phi”或“ cos 𝜑”。

无功功率可以是正值或负值,由角度phi(the)的正号或负号表示。这告诉我们电流是超前电压还是滞后于传输线中的电压。

当无功功率值为正时,它是滞后的,表示感应负载正在消耗无功功率。

当无功功率值是负值时,它是超前的,表示正在传递无功功率的容性负载。

像传统的白炽灯泡一样,纯欧姆负载的功率因数非常接近1。这意味着电压和电流同相,因此传输线中几乎没有无功功率。

功率因数为正时,它们越接近零,电压和电流之间的相位差就越大,并且传输线中存在的无功功率就越大。这与负功率因数相似,只是方向相反:在PF = -1时,电压和电流之间的相位差为180°。

功率与能量-有什么区别?

术语“电能”和“功率”不可互换,因为它们不是同一件事。 使用我们之前的水类比,很容易说明这种差异:

Illustrated difference between electric energy and electric power

功率表示容量,而能量表示随时间推移的传递。

功率本质上是软管中水的流量,基于其压力和体积。 电功率以瓦特(W),千瓦(kW)和兆瓦(MW)为单位。

能量是一段时间内通过软管的水量。 这就是为什么您的电费以千瓦时(kWh)为单位的原因。

为什么我们要测量功率?

用世界著名的管理顾问彼得·德鲁克(Peter Drucker)的话来说:“如果无法衡量,就无法管理”。

测量电压和电流只是分析电气系统的第一步,并且可以使用市场上的任何功率分析仪或功率计轻松完成。

但是为了成功地管理某件事,一个人需要尽可能多的信息。这正是功率分析仪的设计目的。功率分析仪使用户仅需进行少量操作就可以轻松地对任何电气系统进行复杂的分析。

随着电力和电力变得越来越重要,至关重要的是,必须以尽可能最高的标准对其进行测量和管理,以确保持续供电并确保使用该电力的设备可靠,安全和高效。从能源生产本身到将其带入家庭和企业的传输阶段,功率分析仪对于进行准确而全面的测量至关重要。

出于各种原因,以尽可能高的精度测量功率很重要:

  • 进行研发以提高产品和服务的性能
  • 提高能源效率
  • 减少成本和时间消耗
  • 符合国家和国际标准确保产品和操作员的安全

功率分析仪做什么?

功率分析仪可以对电气组件,电路和系统进行广泛的测试和测量。一些最常见的分析包括:

潮流分析 用于建立电力系统的组成部分,其中包括电压大小,电流大小,系统的相角phi,有功功率,无功功率,视在功率以及稳态工作时的功率因数。

另外,对于非线性负载,需要测量和分析畸变无功功率以及谐波无功功率。从理论上讲,电压和电流在欧洲具有理想的50 Hz正弦波(而在北美和南美则为60 Hz)。如果只有纯欧姆线性负载连接到电网(例如白炽灯泡,电加热器,交流电动机等),就会出现这种情况。

先前显示的功率三角形仅适用于欧姆负载,但目前,越来越多的非线性负载以及连接到电网的非线性生产单元。这为功率三角形引入了新的维度,即失真和谐波无功功率。这些现象在单独的《什么是电能质量》 [* COMING SOON]一文中介绍。

让我们看一下新的功率三角形:

Power triangle illustrates the relationship between active, reactive, and apparent power, including the new dimension of distortion and harmonic reactive power新功率三角形说明了有功,无功和视在功率之间的关系,包括失真和谐波无功的新维度

在下面的示例中,线电压将交流电馈入系统,然后开关整流器将其转换为LED所需的直流电。 看一下测量设置的示意图:

Schematic diagram of a LED testing power measurement set-up with both the AC and the DC voltage and current waveforms measured with the power module from Dewesoft

LED测试功率测量设置的示意图,其中使用来自Dewesoft的功率模块测量的AC和DC电压和电流波形

当前,有越来越多的非线性负载(镇流器,整流器,逆变器,个人计算机等)连接到电网,以及非线性发电单元(风力,太阳能和其他形式的能源发电)。 因此,电压和电流波形失真,而不是理想的正弦波形。 因此,必须进行谐波分析才能确定这些非线性负载对电气系统中电流和电压的影响。

短路分析提供有关电气系统所有可能运行情况的信息,并确定系统中各个组件干扰或承受电路中电流大小的能力。

协调分析 用于支持过流保护的发展。 为了确定理想的工作范围,它考虑了保护装置的特性,包括其尺寸和设置。

 

Dewesoft功率分析仪  不仅是世界上最小的功率分析仪,而且还是功能最强大的分析仪。 灵活的硬件平台与强大的软件功能相结合,为任何类型的电气测量提供了独特的测试可能性。 Dewesoft功率分析仪可以计算100多个功率参数,例如P,Q,S,PF,cos phi等。

它还提供了其他仪器的一些功能:

  • 原始数据记录功能
  • 示波器
  • FFT分析
  • 谐波
  • 等等

所有这些计算都可以实时在线,后处理或同时进行。

Dewesoft power analyzer functionalitiesDewesoft功率分析仪在单个设备中结合了多种仪器和功能-功率分析仪,FFT分析仪,原始数据记录仪,示波器,谐波分析仪,温度记录仪,振动记录仪等。

Dewesoft R8功率分析仪可配备多达64个高速模拟输入(每通道16位和5 MHz带宽时高达1 MS / s的速度),可在一个盒子中进行电压和电流测量。

The Dewesoft R8DB power analyzer is capable of 32 high voltage and 32 current channel in a single box with RAW data storing and real-time powe analysisDewesoft R8DB功率分析仪可以配置64个通道,可以选择以适合多合一测量设备的测量应用

输入端在传感器侧(通道到地面)以及通道到通道,甚至隔离的传感器激励,都被完全隔离。 真正的光电隔离意味着更少的噪声,避免接地环路以及出色的信号质量。

高压输入直接通过1600 V DC / CAT II 1000 V / CAT III 600 V保护装置进行测量。 可以使用高精度电流传感器来测量电流, 例如零通量电流传感器,AC / DC电流钳,Rogowsky线圈和分流器。

Dewesoft current tranducersDewesoft提供了范围广泛的电流传感器和电流传感器,可满足任何电流测量范围和精度要求

虽然它是功率分析仪,但它也可以测量各种其他信号类型,包括 加速度计应变片力、以及负载传感器热电偶RTDs计数器和编码器GPS, CAN总线、XCP、FlexRay、甚至视频所有通道彼此同步。

Typical 3-phase delta measurement screen from DewesoftX power analysis softwareDewesoftX功率分析软件的典型三相三角形测量屏幕

SIRIUS XHS-下一代功率分析仪

SIRIUS XHS功率分析仪 是SIRIUS系列的最新版本。 它是一个高速数据采集系统,能够以高达15 MS / s / ch的速度记录8个模拟输入,并具有高达5 MHz的带宽

The new SIRIUS XHS power analyzerSIRIUS XHS展示了四个HV放大器和四个LV放大器

它采用了全新的HybridADC技术,能够进行高带宽瞬态记录和超高动态,无别名的数据采集。 无混叠滤波允许采集动态范围高达160 dB的信号。 较高的通道间和通道对地隔离可防止过高的电压损坏系统,并避免接地环路。

SIRIUS XHS功率分析仪内部的新型HybridADC技术

在大多数功率分析应用中,SIRIUS XHS分别配置有四个高压(HV)和低压(LV)放大器:

  • SIRIUS XHS HV高度隔离的CAT II 1000V高压模拟输入。 该放大器可直接测量20 V至2000 V峰值范围,带宽为5 MHz,精度为0.03%。 该放大器非常适合直接连接高压信号。 此放大器的连接器始终是绝缘的安全香蕉插孔(红色/黑色)。
  • SIRIUS XHS LV:高度隔离的低压模拟输入。 该放大器可以测量0.05 V至100 V的范围,具有5 MHz的带宽,精度为0.03%,并且可以激励选定的传感器(需要DSUB9连接器进行传感器激励)。 该放大器非常适合直接连接低压信号和电流传感器。 该放大器的连接器可用于DSUB9或BNC。 请注意,DSUB9连接器还提供传感器激励以及用于智能传感器设置的TEDS。

当使用DSUB9连接器时,该放大器还接受 DSI系列智能接口适配器从而允许将其他类型的传感器连接到每个LV通道。 这些包括:

  • DSI-ACC 用于IEPE加速度计和麦克风
  • DSI-CHG 用于电荷式加速度计
  • DSI-RTD 用于RTD温度传感器
  • DSI-TH 用于热电偶(J,K,T等)
  • DSI-LVDT 用于LVDT位移/距离传感器

When any DSI model is connected to an LV channel, Dewesoft X data acquisition software automatically detects it (using TEDS sensor standard), and configures that channel for it, setting the input type, gain, range, and scaling to be appropriate. The user can make further settings, and save them into the on-board sensor database.

Noise floor, common-mode rejection, gain and offset drifts of both amplifiers at lower bandwidth are comparable to the standard DualCoreADC SIRIUS line of instruments.

These amplifiers are perfect for e-mobility measurements, where the highest precision such as power analysis is an absolute necessity.

内置FFT分析的功率分析仪

Conventional power analyzers use zero-point detection to determine the periodic time. This means that they evaluate when the voltage or current crosses that x-axis and use that value to calculate the periodic time. 

Dewesoft on the other hand uses a special FFT (Fast Fourier Transform) algorithm to determine the periodic time (frequency).

Based on this predetermined period time, an FFT analysis of voltage and current can be done for a definable number of periods (typically 10, if the system’s base frequency is 50 Hz), and at a selectable sample rate. The FFT analysis yields an amplitude for the voltage, current, and the cos phi for each harmonic. 

The Dewesoft power module has a built-in FFT analyzer in addition to the other display typesThe Dewesoft power module has a built-in FFT analyzer in addition to the other visual display types

多相功率分析仪

In the Dewesoft X power module, there are several predefined system configurations available to choose from. The most common ones are:

  • Direct current, 
  • 1-phase
  • 2-phase - is used, e.g. with special types of motors 
  • 3-phase star
  • 3-phase delta
  • Aron and V configuration is basically star and delta configurations but measuring only two currents instead of three. This is normally done as a space-saving or cost reduction measure.

Special configurations such as 6-, 7-, 9- or 12 phase motor measurement can be done with multiple single-phase or 3-phase systems and adding up the power values in the Math library. This means that power can be measured at multiple points completely synchronous. 

In the math library, the power modules can be further refined, for example, the efficiency can be calculated automatically. This is also very helpful when measuring multi-phase motors (6 to 12 phases).

The Dewesoft power module can be configured for 1, 2 and 3-phase systems. These can be combined to create 6, 7. 9 or even 12-phase systemsThe Dewesoft power module can be configured for 1, 2, and 3-phase systems. These can be combined to create 6, 7. 9 or even 12-phase systems

Engineers can simply select one or more of the systems that they are measuring from this list:

  • 1-Phase 
  • 2-Phase
  • 3-Phase star
  • 3-Phase delta
  • 3-phase Aron
  • 3-phase V
  • 3-phase 2-meters

In addition, a wide range of other choices is available, including the line frequency, output units, frequency source (the channel to be evaluated to determine the exact frequency), phase, and more.

Due to the modular design of Dewesoft measurement devices, the user is never limited to only measuring power values. Dewesoft DAQ systems can connect to virtually every sensor in the world, which means that the engineer can also measure temperature, force, vibration, sound, GPS, video, speed, RPM, torque, etc.

Dewesoft power analyzer schematic

The Dewesoft power analyzer wiring schematic for testing inverter and electric motors

Engineers performing tests on electric or hybrid vehicles may also want to measure the speed of the car, the battery temperature, CAN bus data, GPS position, and even plot its exact location on a test track. 

Instead of using two, three, or even more different measuring instruments, Dewesoft offers all measurements to be recorded simultaneously within a single instrument. This brings several key advantages:

  • No need to merge the data together manually after the measurement.
  • Data is completely synchronized down to a single sample.
  • All the data can be viewed on one screen and written to one data file.
  • Configuring and using only one DAQ system and software saves a lot of test preparation time.

Dewesoft Power Analyzer Explained Live at the Battery Show Expo

传感器数据库提高了电流和电压测量精度

It should be noted that every amplifier, current, and voltage transducer has some kind of inaccuracy or non-linearity. However, with Dewesoft power analyzers, these errors can be measured ahead of time and entered into an XML sensor database. Dewesoft X software applies correction factors in real-time, resulting in more accurate readings and results.

Dewesoft X analog sensor databaseThe Dewesoft analog sensor database

The built-in sensor database also eliminates errors caused by manual data entry mistakes. Selecting a transducer from the list rather than entering the parameters manually not only saves time, but it prevents typographical errors which can lead to wrong scaling or gain selections.

Inside the sensor database, scaling can be set up using y=mx+b formulas, look-up tables, polynomials, and even transfer curves. This only has to be done once for most sensors. Engineers can add, edit and delete sensors, and update their calibration information at any time, including CAL due dates, etc.

The sensor database’s units are based on and derived from the seven international SI unit “defining constants”:

  • Length - meter (m)
  • Time - second (s)
  • Amount of substance - mole (mole)
  • Electric current - ampere (A)
  • Temperature - kelvin (K)
  • Luminous intensity - candela (cd)
  • Mass - kilogram (kg)

So while they are metric at their core, such as m/s2, for example, the user is free to select G or g, in this case. Therefore the output engineering units can be comfortable for all users worldwide. 

Dewesoft software also includes sensor databases for counter/encoder/RPM sensors.

用Dewesoft测量电流

Current measurement is usually divided into two major groups:

  • Direct 
  • Indirect 

Direct” - is when the conductor must be disconnected and a sensor is connected in series with the circuit. This method works without any additional circuits. 

The most common direct current measurement device is a shunt resistor, which is then connected in series with the circuit. A shunt resistor has a very low resistance which has been very accurately determined by the manufacturer. A shunt resistor works on the principle that when the current flows through this resistor, there will be a very small voltage drop that we can measure and convert to current using ohm’s law.

Typical shunt current measurement hook-up
Typical shunt current measurement hook-up

We can measure this drop and apply Ohm’s law to calculate the current.

Graphical representation of Ohm’s Law
Graphical representation of Ohm’s Law

In addition, the accuracy of the resistor is an important factor, since this directly affects the accuracy of the measurement itself.

Dewesoft DSIi-10A current shunt adapterDewesoft DSIi-10A Current Shunt

Dewesoft offers several compact size current shunts, each designed with a different burden resistor inside, intended to measure different current ranges. These shunts have been engineered to have the least possible effect on the circuit itself. 

DSI adapters can be plugged into virtually all Dewesoft data acquisition devices. The isolated analog inputs of Dewesoft amplifiers is a crucial factor in ensuring accurate measurements, since the shunt is connected directly to the circuit being measured, and isolation between the circuit and the measuring system is always important. Isolated inputs mean that you can place your shunt on the low-side or high-side of the circuit, and not worry about a ground loop or common-mode measuring errors.

Considering Ohm’s law again and the interlocking nature of voltage, current, and resistance, it is absolutely clear that a DAQ system must be able to make a very accurate voltage measurement and resistance measurement in order to make an accurate current measurement.

Indirect” - is when the current sensor does not make contact with the circuit directly. Instead, it measures the magnetic field that is induced when current flows through a conductor and then converts it to a current reading (Electric charges produce electric fields).

The advantage of indirect current measurement is galvanic isolation of the sensor from the conductor and the fact that the circuit itself does not have to be disturbed or disconnected. It also allows very high currents to be measured.

Dewesoft supports nearly all of the current transducers available on the market today. Some of the current transducers can be powered directly from the measurement device and some current transducers require an external power supply, as the amount of excitation power that they need cannot be delivered by the measurement device. 

Dewesoft has a solution for this: the SIRIUS PWR-MCTS2 is a power supply unit for powering these current transducers directly from Dewesoft instruments without any third party external power supply devices. The SIRIUS PWR-MCTS2 is offered in a compatible SIRIUS or SIRIUS XHS modular chassis or directly into a SIRIUS-based rack chassis such as R2DB, R3, R4, or R8 data acquisition system.

SIRIUS R8 with multiple measurement slices including rack compatible SIRIUS-PWR-MCTS2 as well as a modular chassis SIRIUS-PWR- MCTS2 and a SIRIUS 4xHV 4XLV

SIRIUS XHS-PWR用于测试混合动力和电动汽车

Another innovation is the SIRIUS XHS-PWR, a new version of the classic SIRIUS DAQ system dedicated to testing hybrid and electric vehicles. It features a patented DC-CT current transducer technology that allows very precise current measurements, even in the most demanding applications, such as very high current peaks as well as leakage current testing.

The SIRIUS XHS-PWR with integrated DC-CT current transducerThe SIRIUS XHS-PWR with integrated DC-CT current transducer

This new instrument is perfect for e-mobility measurements, where the highest precision such as power analysis is an absolute necessity. The current transducer uses patented DC-CT® technology based on the Platiše Flux Sensor. It offers ranges of 100A, 500A, and 1000A, packed into a very small chassis, 1 MHz bandwidth, immunity to external magnetic fields, low offsets, and excellent linearity.

Typical in-vehicle power test, showing additional inputs like CAN bus, video camera, and real-time GPS position superimposed over a mapTypical in-vehicle power test, showing additional inputs like CAN bus, video camera, and real-time GPS position superimposed over a map

The amplifiers can also measure voltage 2000V peak (CAT II 1000V) with up to 5 MHz bandwidth

The SIRIUS XHS-PWR data acquisition system with integrated dc-ct tranducer for electric vehicle testingThe SIRIUS XHS-PWR

This instrument has two inputs:

These inputs connect directly to the power line of the vehicle, for the ultimate in e-mobility testing convenience, bandwidth, and accuracy. It offers an IP65 degree of protection which allows the usage in harsh environments and during rough drives.

Comparison table of DC-CT current transducer versus other current sensor types:

  Type Isolated Range Bandwidth Linearity Accuracy Temp. drift Consumption
DC-CT DC/AC Yes High High Excellent Very High Very Low Medium
Fluxgate DC/AC Yes High High Excellent Excellent Low High
Hall DC/AC Yes High Medium Medium Medium High Low-Med
Shunt DC/AC No Medium Medium Good High Medium High
Rogowsky AC Yes High High Good Medium Low Low
CT AC Yes High Medium Medium Medium Low Low

兼容的电流互感器 

Below is a table that gives a short overview of the current transducers that are available and which characteristics these transducers possess, as well as for which applications they are best suited. 

Overview of current transducers and their application areas

Overview of current transducers and their application areas

Properties Applications
Type AC DC Range Accuracy Bandwidth Pros Cons Power Analyzer E-mobility Grid monitoring
Iron-core current clamps YES NO 5 kA 0,5 - 4 % 10 kHz Cheap Heavy
Inflexible
Low bandwidth
NO NO YES
Cheap Rogowsky Coil YES NO 10 kA 1 % 20 kHz Rugged
Flexible
Linear
No magnetic influence
Overload withstand
No DC measurement
High position errors
NO NO YES
Good Rogowsky Coil YES NO 50 kA 0,3 % Up to 20 MHz Rugged
Flexible
Linear
No magnetic influence
Overload withstand
No DC measurement
High position errors
PARTLY PARTLY YES
Hall-compensated AC/DC current clamp YES YES 300 A 1,5 % 100 kHz AC/DC measurement
High accuracy
High bandwidth
Clamp can open
Low measurement range YES YES YES
Fluxgate AC/DC current clamp YES YES 700 A 0,3 % 500 kHz AC/DC measurement
High accuracy
High bandwidth
Clamp can open
Needs external power supply YES YES YES
Zero-flux current transducer YES YES 2000 A 0,002 % Up to 300 kHz AC/DC measurement
High accuracy
High bandwidth
Low phase error
Low offset
Can not be opened
Needs external power supply
YES YES YES

Dewesoft designs and produces world-renowned measurement and data acquisition equipment for a wide range of industries and applications. A focus since the early 2000s has been power analysis and power quality analysis. 

Little did we know back then that automobiles would be turning electric at such a rapid pace as they are today. And that’s just one application where portable, high-performance power analyzers and power quality analyzer measuring instruments are essential.

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