Everyone knows that THD is Total Harmonic Distortion, which is divided into voltage THD and current THD, which indicates the severity of voltage and current waveform distortion. The larger the harmonic content of the waveform, the more serious the waveform distortion and the larger the THD value. Conversely, the lower the THD value.
So when THD is measured,
- How many harmonics should be counted?
- What are the limits specified in the national standard?
- How much THD is hazardous to electrical equipment for the end user? Do you have any experience points?
Different users have different requirements, and the corresponding standards and regulations are also different, so it is necessary to clarify the purpose of the test in advance (evaluation of power supply quality or daily maintenance of power supply within the enterprise, equipment troubleshooting?). ）； Planning the test points and understanding the tolerance of the equipment can determine whether the THD is qualified?
Sixth issue
What is the significance of THD at the 40th, 50th and 100th harmonics?
1. First: power quality assessment
Electric energy is also a commodity, as a supplier (power company) test is to ensure the quality of the public power grid of various power supply voltage levels, mainly voltage quality, so as to ensure the normal operation of the user's electrical equipment; At present, most of the standards for power quality assessment are prescribed for testing and evaluation at the PCC point, which is the location where the user purchases electricity from the supplier.
On the other hand, the user's load type, capacity or working status will affect the power supply system, causing waveform distortion or voltage fluctuations. Another test purpose of the power company is to regulate and avoid the influence and pollution of the user, focusing not only on harmonic voltages but also on harmonic currents. In addition, the continuous development of the quantity and scale of new energy and large-capacity charging piles is also a challenge to the quality and safety of the power grid.
2. Second: daily maintenance of power supply quality within the enterprise
Depending on the user's requirements for the quality of power supply due to different loads, especially sensitive loads such as electronic and computer devices, the technical parameters of the corresponding electrical equipment can be consulted, such as synchronous generators (e.g., diesel generator sets) requiring THD measurements of 100 times.
As a general rule, THD <8% is required at the end load, otherwise it will affect the normal operation or life of the equipment, but some loads will have more stringent requirements, such as medical equipment or computer room equipment.
Therefore, maintaining high power quality is a shared responsibility of both the power supplier and the power user!
3. Third: some standard requirements
• EN 50160 evaluation – requires 40 THD measurements.
• GB/T 14549 – requires 50 THD measurements.
• GB/T 755 – Synchronous generators (e.g., diesel generator sets) require 100 THD measurements.
According to different testing needs, choose the right instrument, and compare the THD test functions of several main models of Fluke:
F1770: 40 times, 50 times, 100 times, and give at the same time!
F1770 Series Test Interface:
|
More on that
|
How to use Fluke Connect™ software with the Fluke 377 FC and Fluke 378 FC FieldSense™ clamps
The 377FC and 378FC clamp meters feature the new FieldSense™ technology, which enables you to measure voltage and current using the jaws.
By integrating Fluke Connect software into many Fluke tools, including the 377 FC and 378 FC clamp meters, you can save on troubleshooting ...
|
|
Introduction and benefits of Fluke multimeters
Fluke multimeter refers to the instrument of the United States brand Fluke, so Fluke multimeter is referred to as Fluke multimeter
Fluke multimeters are an indispensable measuring tool in our daily lives. According to different use occasions, we should choose the right multimeter. Multimeter...
|
|
Fluke F2052 F2062 Advanced Finder Kit
01 Visual and intelligent indication of cable direction, showing professionalism
Smart Sensor™ (Fluke 2062 only) makes the search smarter. It locates and displays energized power inside walls, floors, and ceilings on a high-resolution 3.5-inch TFT LCD color display.
|
|
Fundamentals of leakage current measurement
Application note
In any electrical device, there is a certain amount of current flowing to the ground through a protective ground conductor. This current is generally referred to as the leakage current. The most common way for leakage current is to flow through the insulation around conductors, as well as through filters that protect electronics around your home or office. Then it would be ...
|
|
Fluke Networks announces the expansion of the network connectivity testing capabilities of the LinkIQ™ Smart Chainline + Network Tester
Fluke Networks announced the upgrade of its LinkIQ™ Smart Link Pass Cable + Network Tester to expand its ability to test IP network troubleshooting and industrial Ethernet cabling with a user interface in 12 languages. New LinkIQ devices are equipped with the latest software. The product that has been purchased with ...
|
|
Fluke introduces the DSX Series for Versiv2 certification testing
You may be ready to get rid of the 2004 Toyota, which still uses a cassette recorder and has driven 280,000 kilometers and honestly, "It's a good car indeed!"
Although you may still be using the now-discontinued DTX tester and have been working for the past few ...
|
|
Use the "sharp eye" to quickly find equipment failures and get twice the result with half the effort!
The Fluke VT08 portable thermal imaging camera can check the operation status of power distribution equipment, quickly locate the temperature measurement value of the observation target, take pictures to record the operation status of the equipment, and immediately find hidden dangers and problems in the equipment.
Today we have invited a man who works in a cable company.
|
|
Fluke magnetic lanyards are launched
In addition to providing safe and durable multimeters, clamp meters and other host products, Fluke has also developed a series of accessories to expand the use of instrumentation. These include stylus for various applications, AC and DC current clamps, thermocouples for different applications, etc.
Among the more than 200 accessory products, ...
|
|
The Fluke II900 Industrial Acoustic Imager won the 2019 Product of the Year Award
On September 18, 2019, the authoritative annual new product selection activity in the field of industrial automation - CONTROL ENGINEERING China 2019 Best Product Award Ceremony was held in Shanghai Jinguyuan Howard Johnson Hotel, Fluke ii900 industrial acoustic imager, won the "Contr ...
|
|
【Application case】The use of multimeter in the new energy industry
1. New energy photovoltaic industry
Zhang Gong is the equipment department of a new energy company, which mainly manufactures solar cells through photovoltaic automation equipment. Zhang's daily work includes electrical maintenance, mechanical maintenance and software maintenance. The company has 9 large production lines, each with more than 30 machines...
|
|
Introduction to Fluke thermal imaging cameras and how to use them
The Fluke infrared thermal imaging camera uses an infrared detector and an optical imaging objective lens to receive the infrared radiation energy distribution map of the measured target and reflect it on the photosensitive element of the infrared detector, so as to obtain an infrared thermal image, which corresponds to the thermal distribution field on the surface of the object. So so...
|
|
Tips for using a thermal imaging camera in the field - how to choose the right focus?
At present, there are four main focusing methods of thermal imaging cameras: no focus, manual focus, autofocus, and laser autofocus.
Some models of thermal imaging cameras will combine these four focusing methods, such as laser autofocus + manual focus, autofocus + manual focus, non-focus + manual adjustment...
|
|
Fluke 301C Multi-Clamp Meter for Quality Control Engineers
"Before the test, the pump resistance of the machine should be measured, and the resistance diode capacitance can be switched by pressing the selection button, and the current and voltage can be measured at the same time, which is very convenient."
1. A variety of functions, one machine to get
Before testing, the machine's water pump resistance should be ...
|
|
Small size, good looks, big use! F301C blade pliers help industrial control operation and maintenance
As a commonly used testing tool, in addition to being easy to use and handy, the appearance is not good-looking, whether it is ergonomic, whether the design is simple and atmospheric, and it is also a lot of advanced requirements that Xiaofu has heard recently. It seems that even if it is a small tool, many of our engineers still want to highlight ...
|
|
Fluke PV + Energy Storage Industry Solutions
Photovoltaic + energy storage industry solutions
The dual carbon goals of "carbon peak" and "carbon neutrality" drive the development of new energy industries such as photovoltaic and wind power, while new energy power generation has little room for human intervention, large energy difference between peak and valley value, and does not fully match the electricity consumption period.
|
|
Fluke multimeter model
A Fluke multimeter is a magnetoelectric meter that can measure a variety of electrical parameters such as AC and DC current, voltage and resistance.
Compared to other similar test tools, Fluke DMMs/multimeters are more widely used and have more comprehensive fault finding. All designs are tested to the limit: ...
|
|
Tutorial on how to use a Fluke multimeter
Fluke Multimeter Tutorial.
Speakers, headphones, dynamic microphones: Using the R×1ω setting, any pen connected to one end and the other pen touches the other end, and it will normally make a crisp clicking sound. If it doesn't sound, the coil will break, and if the sound is small and sharp, there will be a lap ...
|
|
Power Quality Measurement Technology No.5 - How is the national standard stipulated in the national standard for voltage harmonic limits?
Preface:
Before talking about the requirements and limits of the national standard for harmonic voltage, let's first clarify why the national standard should limit the harmonic voltage?
Mainly due to the impact of excessive voltage harmonics on the load and power supply equipment:
1. Cause abnormal electrical equipment (motors, transformers, etc.) ...
|
|
New Product Releases | Photovoltaic multi-function IV curve tester
All-in-one functionality
Competent in PV system performance and safety testing
Ground on-resistance
Visual inspection
Save data locally
Start the test with one click
Automated testing
polarity
Open circuit voltage Voc
Short-circuit current IsC
AC/DC power
Insulation resistance I-V curve
Diodes and surges ...
|
|
Fluke 55X0A High Performance Multi-Product Calibrator
· A single instrument constitutes a small calibration laboratory
· Multiple signal output of single machine
• Matching options to calibrate a wide range of electrical products
· Full-color touch screen, friendly operation interface
|
|
Contact
working hours
