Power Quality Matters involve detecting phase imbalances and ensuring that all phasors have equal magnitudes and are symmetrically phase-shifted by 120 degrees relative to each other.
Unbalanced network conditions in power supplies can be deceptive because phase-to-neutral voltage measurements might not reveal the full picture. Here are why phase-to-phase voltages might not be close to each other even if phase-to-neutral voltages are: Unmatched Impedance: If the impedance in the transformer banks is unmatched, it can cause unbalanced conditions that are not […]
Power Networks in Flux – Balancing the Unbalanced Read More »
On the 2nd of October 2023, I published an article with the heading “Phase Imbalance in Distribution Networks” in which I stated that “In a recent unrelated “survey”, I came across a 10-minute averaged voltage unbalance of 327% between Phase 2 and Phase 1”. I also asked the question: is Eskom aware what is happening
Contravention of Fiduciary Duties Read More »
It is a known fact that there is a growing shift towards renewable energy sources as well as buying and selling electrical power which most often necessitates the use of HVDC transmission systems. Both the solar power generation and HVDC transmission systems make extensive use of power electronics devices. In future, more-and-more grid-forming converters (GFMCs)
Compensating For Power Quality Issues Caused by Power Electronics Devices Read More »
On September 24, 2023, I posed an article in which I explained how poorly maintained switchgear could lead to long-lasting power quality issues. In that article, which was based on an actual incident in Benoni, Gauteng, South Africa, I mentioned that the voltages of two of the three phases increased by more than 51% while
Unfazed Attitude Towards Power Quality Issues Read More »
In the latest newsletter which would be published on November 14, 2023, I am making another attempt, this time, to catch the attention of accountants and financial officers explaining to them how unbalanced voltages, phase-shift variations, and harmonics disturbances would result in enormous economic losses. But first, I must go back to a previous blog
Cost of Complacency Read More »
In the mid-eighties, as part of my function, I was asked to help and solve a problem of one of our client’s constant complaints about “power failures”. This client was the National Accelerator Centre (NAC) in Faure, Western Cape. Today it is called the iThemba LABS. According to their website, this is the largest accelerator
Consequence of Weaknesses in Power Quality Read More »
Throughout my time in the power transmission and distribution industry I have probably had experiences that many others may never have. In a previous post, I talked about the current and voltage unbalances and how a large factory in the Western Cape in South Africa was severely affected by negative phase sequencing. In this post
Power Network Disturbances Read More »
To mitigate the effects of Load-Shedding, many homeowners have decided to install PV Solar Energy systems. And, as I said before, they are more worried about how much it would cost than the quality of the products. If they can pay the lowest possible price for the entire installation, they are happy and do not
Power Quality Issues Caused by Distributed Generation Read More »
Any repetitive signal, such as three-phase Alternating Current (AC) Voltages and Currents, can be represented as the rotation of a vector around a point. In a balanced three-phase network, the magnitudes of the voltages and currents in all three phases are the same and these phases voltages and currents are shifted symmetrically by 120 degrees
Rotating Voltage and Current Vectors Read More »
Practical imperfections which can result in unbalances are: A three-phase equipment such as induction motor with unbalance in its windings. If the reactance of three phases is not same, it will result in varying current flowing in three phases and give out system unbalance. With continuous operation, motor’s physical environment cause degradation of rotor and
Causes of Unbalanced Voltages and Currents Read More »
