ELECTRICAL PE REVIEW, INC.
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Zach is probably better than all of my professors I had in college at explaining difficult power concepts. I do not think I would have passed the PE exam this time without using the Electrical PE Review course, and I can't recommend it highly enough for anyone preparing to take the Power PE Exam." "As a participant in multiple Electrical PE study courses (TM, SoPE) and multiple exams, I have to say, Zach helped me get over hump to pass the PE exam. The live classes are one of the best reviews you could have. Thanks Zach for your time, help, and for creating this course to help us/me pass the PE Exam!!" Next, since this is a three phase transmission system, the line current in the system will equal the phase current in the single phase equivalent circuit (think of wye : wye relationships where I_phase = I_Line). The A line current in the transmission system during the single line to ground fault is 1,420A(rounded to the nearest amp). The fault current is equal to 1,420 amps (rounded to the nearest amp) in the single line fault for the transmission system in the given problem. In our calculations we are using the secondary values: Now that we are familiar with the maximum power relationships for the three phase delta transformer, let’s look at what happens when one winding is removed and we are left with the open delta transformer connection. So far, nothing has changed for the delta A-phase and C-phase voltage, but we are not so sure about the delta B phase voltage just yet: Even though the open delta can still serve a three phase load provided it has enough capacity, to find the maximum power we will only be looking at the two windings that remain. Note that we are not using line values because we want to find the complex sum of both remaining individual single phase transformers that each make up the two remaining phase windings of the open delta transformer: This only works we are comparing an open delta three phase transformer with the same single phase transformer ratings. For example, if a three phase delta transformer loses one of its windings, or, if the same rated single phase transformers are used to make both a three phase delta transformer and an open delta transformer. Ex 3. Three single phase transformers rated for 10MVA 13.8kV/4,160V are connected in delta to form a three phase transformer. While in operation, one winding fails without damaging the other two. The transformer continues to provide power in an open delta configuration. Determine the percentage of power that the open delta configuration is able to supply compared to when all three windings were in service. In this article we are going to address two main questions: The same questions are in the same order as the older edition and are word for word, number for number, exactly the same including the provided solutions. P.S. Not sure what additional books to buy to help you prepare and to take with you to the exam? Check out our The addition of the following sub-categories: Single-phase circuits, DC circuits, and Single-line diagrams. In my opinion, these are all sub-categories that have already been on the PE exam in the past. For example, in the older sample exam you couldn’t flip pages very long without seeing a single line diagram of a transmission system or of a three phase system. DC circuits were also fair game under batteries and power electronic devices, and single-phase circuits were already extremely common when solving for motor equivalent circuits and single-phase devices like phase transformers. Although these are new sub-categories my opinion is that once again NCEES is just trying to be more clear with you about their expectations. To help clear things up, here is an in-depth break down on an example question that is similar to what you can expect to see on the NCEES Electrical Power PE Exam. Electrical PE Review – Calculating Base Impedance with Three Phase vs Single Phase Values The catch here is that we don’t know either of the transformer impedances in ohms, we are instead given their percent impedances. Since we are working with impedances, we will need to plug in the impedance formula that uses the square of the voltage divided by power: is a professionally licensed engineer in the state of Florida and earned a Bachelor of Science in Electrical Engineering from an ABET accredited university. He has industry experience in the design, installation, maintenance, and troubleshooting of commercial buildings, healthcare facilities, industrial facilities, measurement and instrumentation, power generation, electrical distribution and transmission, and automation & controls. In recent years he has fulfilled the role of front line people leader overseeing the hands on day to day electrical maintenance for a 24 hour around the clock global industrial manufacturing employer in areas of material handling, chemical production, rotating machinery, and power generation of two 50 MW steam driven turbo generators. He has a passion for teaching and a love for making misunderstood subjects clear by drilling down to the fundamentals for simple, intuitive understanding. He passed both the E.I.T. and P.E. exam on the first try.