Should we be concerned about high electromagnetic fields? Magnetic fields are produced by current; and electric fields by voltage. Concerns about exposure to high levels of EMFs are mainly about magnetic fields. So where do most people get exposed to EMFs?
People are mostly exposed to levels of EMF from wiring in their own homes and electrical wires running along streets. However, if substations are a source of EMF then how are they emitted?
What Are Electrical Substations and Are They Dangerous?
Electrical substations generate electric and magnetic fields through transformers and equipment contained inside these units as well as cables running in and out. Some substations are interconnected in such a way that they create high magnetic field levels over a wide area that can affect public buildings and houses.
From the perspective of high EMF fields, the transformer usually emits the most radiation. Older substations, with original equipment and wiring, tend to emit more radiation than newer ones. Apart from people who are particularly sensitive to EMFs, the detectable EMF radiation from a substation does not have any significant effect on the general health of most people.
Do Substations Emit EMFs?
All substations emit some level of EMF radiation and although they are non-ionizing, high levels can be harmful. As one component of an electrical generation, distribution, and transmission system, a substation performs many functions such as transforming voltage from low to high and from high to low voltages. Some contain transformers for this purpose.
Electrical substations emit low-frequency EMF radiation with electric and magnetic components that create an electromagnetic field. Electric fields are of no concern as they do not have the power to penetrate the walls of a substation.
Different Types of Electrical Substations
There are many different types of substations. In residential areas, these substations can be found every hundred metres or so with fields that are rarely wider than about 5 meters.
Larger national grid installations range from small ones of about 10 meters wide to national grid installations that are 100 meters wide or wider. These are usually located far from buildings where people work or live.
How do Electrical Substations Emit Electromagnetic Fields?
EMFs are created whenever an electrical current flows through a conductor. This current can counteract current flowing in the opposite direction from an adjacent conductor. This knowledge is key for technicians designing electrical equipment that will produce low EMFs. The transformer is the largest electrical device inside a substation and will therefore emit the most radiation.
Substations serve as connection points between a transmission network and electricity generators, lower voltage distribution networks, and large load customers. As they do not generate power, they are generally quiet apart from a low hum from the transformer when standing near its boundary.
As an example, there are 91 ElectraNet substations around South Australia involved in moving high-voltage power to where it is needed, sometimes over very long distances. The detectable magnetic field of a substation typically ranges from 3 to 8 metres. In residential areas magnetic fields peak during high power consumption periods, typically between 8.00 am and 6.00 pm, and are weakest during nighttime.
If you are concerned about electromagnetic radiation, Compliance Engineering offers services to survey electromagnetic radiation sources and, where applicable, can recommend shielding solutions. A formal test report provides detailed exclusion zones and recommendations on restricting access.
Contact get in touch with us for more information on EMF exposure limits and EMF shielding solutions. In addition, we also offer RCM testing, interference investigations, vibration and shock testing, environmental testing, and CE testing among others.