Koula R.

A very interesting white paper on reduced voltage auto transformer failures a counterpart recently found. I would certainly encourage reading this document.

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If It’s Not Broken, Don’t Fix It The aging process starts the moment new substation equipment is put into service; how quickly it happens depends on a number of factors, including the equipment’s use, the environment, the quality of maintenance, and many more. However, things aren’t the same anymore. Digital substation equipment changed the game, and as it appears so far, such equipment will likely last much shorter than old analogue devices. Simply, electronics cannot last that long.

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Between six and twelve months is the typical recommendation from most manufacturers for both exterior and interior checks. Internal inspections may not be necessary as often if appropriate external checks are conducted. It is important to base the inspection schedule on the breaker’s interrupting duty. After the first major disruption caused by a malfunction, it is advised to conduct a thorough internal inspection. Assuming everything is in order on the inside, it’s possible to gradually increase the number of fault interruptions before conducting an inspection. Based on past experiences, high voltage CBs (HV CBs) rated at 230 kV or more can withstand up to five fault interruptions between inspections, while CBs rated at less than 230 kV can manage up to ten fault interruptions.

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Here's a multichoice question to challenge your understanding of electrical systems: What is the primary purpose of a circuit breaker in an electrical system? a) To measure electrical current flow b) To interrupt the circuit during overcurrent conditions c) To regulate voltage fluctuations d) To connect multiple circuits together Reply with your answer in the comments! Let's see who gets it right! ⚡️ #ElectricalQuiz #TestYourKnowledge #peqvi

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Turn Problems into Power: Overcome the Top 5 Challenges of Substation Design https://bit.ly/3Uw42CZ

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Per-Unit Values: The Secret Weapon in Power System Analysis Per-unit calculations are used all over in power engineering. There are a few reasons why they are still used even though we are in the age of computers. The first is that it allows for easy back-of-the-napkin calculations. When a transformer, for example, is put into a model, it will have an impedance of around 5 to 15% of its base MVA. When it is put into the model, it is converted to the model's base, which is usually 100 MVA, but this is just an arbitrary decision. Once everything is brought to the same base, the transformer is no longer stepping up or down the voltage but is just represented in the per-unit model as an impedance. From there, power flows and fault currents can be calculated by hand for sanity-checking models. This avoids the headache of needing to reflect secondary ohmic impedances from the secondary to the primary or vice versa of a transformer. Once the per-unit currents, voltages, and power flows are calculated, they can be reverted to their bases. If your 10 kV portion of your grid is showing 0.9 pu voltage in your per-unit calculations, that equals 0.9 pu * 10 kV base = 9 kV. Additionally, if you have a region of a grid that has high (>1) or low (<1) voltage, it is easy to see. As opposed to needing to remember that 13.9 kV is high in one part of the grid and 11.8 kV is low in another portion of the grid. One thing that sometimes needs to be kept in mind when working with the various per-unit calculations is that per-unit line-to-line is the same as per-unit line-to-neutral because the assumption is made that a balanced system is being used. (Per Unit Voltage Line to Line) will equal (Per Unit Voltage Line to Neutral). This will look odd in the calculation when compared to ohmic calculations, like the square root of three term just dropped out, but ultimately it makes the calculations easier to do on a napkin. The last reason is probably more important than simplifying things for napkin calculations. Hand calcs are likely not done often anymore due to how readily available and trustworthy fault analysis software is. The biggest reason ,in my opinion, is that a lot of equipment per-unit values tend to fall in a narrow band. Distribution transformers tend to have lower per-unit impedances of around 5%, and your large 100 MVA transformers might be around 15%. The per-unit impedance somewhat scales with the MVA of the transformers and makes it much easier to spot mistakes in the model, which would be very tedious if ohmic values were put into the model instead. Other equipment that tends to fall in a tiny band of per-unit impedance are generators and synchronous and induction motors. This makes it much easier to spot mistakes in the model. Per-unit calculation can simplify analysis for hand calculations but more importantly, it can make model mistakes easier to spot. #utilities #renewables #electricalengineering #energystorage

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In this video I'll show how to use RelayHelper restoring algorithms. In this case, the 7UT613 protects part of the busbar between the power autotransformer and the auxiliary transformer, which is connected to the delta winding. The short circuit was outside the zone, and device worked falsely because current transformer in the second branch was saturated. We're keen on improving signal shape reconstruction accuracy and are exploring the use of artificial intelligence. If you encounter similar cases or have data that could contribute to our training, please share. Your contribution will boost your karma. #RelayHelper

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Today's Insight: Reactive power is not really power at all but represents the product of volts and amperes that are out-of-phase with each other. Most of the equipment connected to the electric supply systems consumes or produces apparent power but not all these control the voltage levels. P Some of the sources and sinks are given in the below diagram. #powersystem #electricalengineering #learningeveryday #loadflow #etap

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VA stands for Volt Amps. This is the measurement for apparent power, which is one of the three types of power in AC circuit.Batteries are DC. DC circuits don't have power factors, so VA isn't applicable to batteries. Batteries are not a constant voltage source.We are only interested in battery capacity, which is only for a specific time, so we can't use Wh instead of Ah for battery as well. Ah is a measurement of charge.VA is a measurement of power, which is not the same as charge. Batteries store charge.Batteries store charge in the form of chemical energy and then convert it into electrical energy to utilize for a specific time. The amount of available charge is the capacity of a cell or battery which may be expressed in Ah (Ampere-hour). #batteries

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Dive into the essentials of 120-V branch circuits, including proper wiring techniques for outlets, switches, and light fixtures. Understanding these principles is key to ensuring safe and efficient electrical systems in both residential and commercial settings. #ElectricalSafety #ElectricalEngineering #NEC #SafetyFirst #ResidentialElectrical #ElectricalSafetyTips #NFPA70E #NationalElectricalCode

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It's a Power electronic device that converts alternating Current (AC) From One frequency and voltage to another without the use of an intermediate DC link. #Electrical_Notes #Free_PDFs

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Experiment: Try to collect, correlate, and operationalize SBOMs for everything in a substation. Matt Wyckhouse and the team at Finite State and Alex Waitkus and the team at Southern Co. tried to do this. They went into the substation, physically inventoried all of their equipment, collected data from their sensors, and started collecting SBOMs from their vendors. Hear about the successes and problems, resolved and open issues, and what asset owners can realistically look forward to if they try to broadly use SBOMs. ----- Note - I rarely have two people tag team in a S4 performance. Matt made it impossible to say no with the very cool, video game inspired graphics they had in this presentation. #s4xevents #sbom #otsecurity

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Tech alert: I have been working on grid-forming control architectures since the very beginning. One challenging (the major!) problem has always been how to retain the grid-forming functionality under current saturation, e.g. after a fault. There are plenty of hackish or over-sophisticated solutions out there but nothing satisfying that simply works robustly and out-of-the-box. We have finally figured it out 👇

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Modern electrical systems utilize miniature circuit breakers (MCBs) for the protection of VT circuits, while historically, fuses were employed for this purpose. MCBs and fuses serve to provide shortcircuit protection at the VT secondary winding, effectively disconnecting the VT supply in the event of a fault. Now, let’s consider a scenario where a VT secondary is linked to an under-voltage protection system, and the VT MCB trips or the VT fuse blows. In such a situation, the under-voltage protection mechanism cannot distinguish between a genuine under-voltage condition and a VT MCB trip. Read more https://lnkd.in/dPC7ywzt

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Undergrounding distribution circuits increases power reliability, but did you know that it’s also a great way to advance resilience? That means you have power no matter the weather. As we face more frequent and severe weather, undergrounding can help your grid weather the storm. https://lnkd.in/gMQFDAJS #Resiliency

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The coil of the magnetic contactor is labeled with terminals A1 and A2, while the power contacts are denoted as L1, L2, and L3, and the auxiliary contacts as 13/14 and 21/22. A notable distinction between power and auxiliary contacts lies in the tips – power contacts L1, L2, and L3 have a semi-circle, indicating their specialized treatment for handling high current. It is important to recognize that the power contacts function as normally open contacts, and when the coil of the magnetic contactor is energized, these main/power contacts transition from an open to a closed position. Read more https://lnkd.in/dCPRmeGe

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I'm excited to offer a one-day course on #power #system #studies with a focus on #IBR (#Inverter-Based Resource) facilities and an introduction to #PSCAD software. This course is perfect for anyone wanting to understand the importance of these studies and how to start working with PSCAD. It's also ideal for those looking to enter this exciting job market. What You'll Learn: Fundamentals of power system studies in #phasor #domain vs. #EMT domain * IBR integration challenges (#distributions and #transmission level) * #Grid_forming_inverters * Key scenarios for conducting EMT studies * Where and how to start EMT studies * Practical training with PSCAD This course is a part of #IEEE Education approved #PDH and #PDU. Upon successful completion of the course, the participants will receive the #certificate. I would like to thank Marjan Alavi, PhD, P.Eng., SMIEEE for her support to make this happen and #IEEE for hosting this event. Join me to gain essential skills and knowledge in this evolving field. Let's power up your career in renewable energy! #PowerSystems #IBR #PSCAD #Engineering #RenewableEnergy #CareerGrowth Registration link: https://lnkd.in/gRGpCN29

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The aging process starts the moment new substation equipment is put into service; how quickly it happens depends on a number of factors, including the equipment’s use, the environment, the quality of maintenance, and many more. However, things aren’t the same anymore. Digital substation equipment changed the game, and as it appears so far, such equipment will likely last much shorter than old analogue devices. Simply, electronics cannot last that long. However, this is yet to be discussed in the coming years. This article tackles electrical substation equipment in general. Although some electrical power equipment has been in use for decades, the majority of it has already degraded to varying degrees. Read more

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