The malfunctioning of an electrical appliance may be critical to production downtime, safety hazards, quality control and communication breakdowns. Normally, a bad electricity quality on the power cables (Power Quality) is the first thought that comes to everyone’s mind when justifying the malfunction. This is because a bad voltage can cause a myriad of problems in any electrical installation.
However, there are other factors or phenomena that may actually be causing the malfunction, which are partially correlated with electricity. One of the main factors is Electromagnetic Compatibility (EMC).
Electrical installations (industrial, commercial, vessels/yachts, datacenters and even residential) are experiencing a rapid increase in the amount of electronic appliances. Their number has been growing exponentially over the years. The rapid expansion of technology is leading to even more complex electrical installations with the following concepts arising:
- Wireless technology and communication protocols (antennas, radio devices, radars, etc)
- Internet of Things (IoT)
- Newer electronics: More compact (smaller) with higher operating frequencies
Whether involuntary or on purpose, the aforementioned concepts create electric and magnetic fields at high frequencies (kHz – GHz) that are present in the air. In other words, an Electromagnetic Field (EMF) produced by various sources is built up in the air. As an example, the purpose of an antenna is to transmit or receive a certain frequency to enable the usage of a wireless communication system. However, newer electronics involuntary present fields in their surroundings, since they need frequencies of kHz-MHz to perform their switching operations, e.g. chopping the electrical waveform from AC to DC. But they were never intended to create fields around themselves. The field strength on the air can be measured and quantified with so-called Radiated EMC Measurements. The frequency scope of Radiated EMC can be seen in the figure below.
How Radiated EMC affects electrical equipment? Malfunction examples
All electrical devices share two common mediums: the electrical installation or cabling and the air or surroundings. A device creating or radiating a frequency through the air is normally called the source. A device suffering from this radiated frequency is called the victim. This means that the malfunctioning equipment is in the vicinity (several meters) from the source. This concept is also known as far-field coupling or Radiated Coupling.
As an example, Radiated Coupling can cause sensible electronic loads to go defect, i.e. electronic chips, but can also create interferences in communication systems or basic communication protocols.
The effect of this field on the victim depends upon the power of the radiating source and effectiveness of the emitting and receiving antenna (the victim becomes a receiver).
HyTEPS Measurement and Investigation Approach
HyTEPS has experience with Radiated EMC measurements which have been increasing over the years. The prerequisities for a successful measurement are to gather information about:
- Problem
- Single Line Diagram
- Transmitting devices present
It is important to understand the problem and document this as much as possible in order to define an investigation approach.
Then, the use of a Microwave Analyser in combination with an “all-in-one broadband antenna” enables a real-time measurement of electromagnetic fields up to the order of several Gigahertz, thus capturing even ultra-high frequencies such as 5G and radar. In other words, the study focuses on real-time spectrum, spectrogram, and density spectrum measurements in order to quantify each frequency present in terms of magnitude (Power and/or field strength) and persistence, and identify a correlation with the problem.
Real-time spectrum
The field strength of a specific location is visualized in real-time, and the maximum value ever recorded is also registered. This helps in identifying the frequencies present and determining how dangerous they might be.
Spectrogram
Once a certain frequency has been identified, it can be individually measured over time (500ms/div example). Therefore, its field strength pulses and persistence can be quantified.
