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 […]
Tag Archives: Power Quality Matters
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.
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 […]
In the mid-1980s, I embarked on a mission to resolve persistent “power failure” complaints from the National Accelerator Centre (NAC) in Faure, Western Cape, now known as iThemba LABS—the largest accelerator facility in the Southern Hemisphere. Invited for private tours, I delved into their operations, even entering the high-stakes environment of the operating room. Witnessing […]
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 […]
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 […]
With our comprehensive Negative Phase Sequence Consulting Services, we deliver expert analysis and innovative solutions to effectively manage negative sequence currents in three-phase electrical systems. Our services are designed to identify and address issues caused by unbalanced loads, faults, and system abnormalities, ensuring system stability, reducing equipment wear, and significantly enhancing overall power quality. We […]
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 […]
Extremely long—hundreds of kilometers—untransposed high and extra-high voltage transmission lines with a flat, horizontal conductor configuration significantly contribute to negative-sequence voltages and, to a lesser extent, zero-sequence voltages. The incidence of negative-sequence voltages rises with increasing electrical load. In the late 1970s and early 1980s, Eskom operated two 400kV transmission lines to the Western Cape: […]
In a balanced three-phase network, the magnitudes of the voltages and currents in all three phases are the same and these voltages and currents phase are shifted symmetrically by 120 degrees to each other. If the magnitudes are not the same and phase-shifts are different from the 120 degrees, the network is unbalanced. Eskom strive […]
When switchgear is poorly maintained and operated continuously, it is only a matter of time before something significant occurs. However, if these extreme events go unnoticed, the consequences can be long-lasting. During load-shedding, circuit-breakers should be opened when load-shedding starts and closed when load-shedding ends. Unfortunately, the contacts of these circuit-breakers are often concealed. As […]
- 1
- 2