Design and Simulation of Automatic Load Touch Changer

1. Introduction

CE 3. 1

This is the third project I did so as a graduate Electrical Executive while chasing my Bachelor of Anatomist in the field of Electrical Anatomist from Balochistan School of Engineering and Technology, Balochistan, Pakistan. I wanted to execute a project that could enable the transformer to attain different voltage levels utilizing a load tap changing transformer and thus wanted to learn about different electric powered/electronic components that might be needed and so learn about its design and how to put into action it. I was able to improve my written and oral display skills as well as my interpersonal skills by the successful conclusion of this task.

1. Background

CE 3. 2

For my third task as an undergraduate in electronic engineering, I needed to start working on a project during my second year. I wanted to find out about different and frequently used electronic/electronic components, the working mechanism and the implementation in complex jobs. This offered as a inspiration to carry out a task on Load Tap changers.

I had researched during my bachelors that Transformer Fill changers are an intrinsic part to any electricity grid whether in big projects or small. I recognized that there have been the Mechanical Fill touch changer and the Electronic Fill Tap Changer. I needed to create an automatic Electronic type Load touch changer to the issues with trustworthiness and maintenance of the Mechanical type.

Also, I found that by using Thyristors to take the on-load current while the primary contacts change over in one tap to another, the design would have no moving parts and therefore have an extended service life. And it is for this reason reason that we selected the "Design of Auto Load Touch Changer" for my task.

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The objective of this project is to design and build a prototype of a fully electronic on fill faucet changer for power transformers by using Triacs as turning devices and microcontroller as the triggering circuit.

CE 3. 4

CE 3. 5

I efficiently completed this job by participating in the following activities:

• I divided my job into Electricity circuitry and Control circuitry.
• I designed the energy circuitry to basically consist of a tapping transformer connected to the load through the transitioning devices.
• I designed the Control circuitry to sense the voltage indication fed from the step down transformer and compare it to a pre-set research value.
• I used a Triac which really is a three terminal semiconductor for handling the existing in both directions.
• I used a Electricity Circuit, Microcontroller Device, Analog To Digital Converter, Zero Crossing Detector, Multiplexer, LCD, Buzzer as the parts of the circuit
• I completed the project within the time frame given by the college or university.
• I conducted complete literature review on all the components used here.

1. Personal Anatomist Activity

CE 3. 6

I contacted a teacher with a concept of executing a project with transformers. Along with my team partner, I put a whole lot of brainstorming sessions and review meetings with my job supervisor to choose a suitable topic. I suggested which i focus on a task that was concerned with developing and fabricating a system based on Automatic Electronic Load Touch Changer of a Transformer and the supervisor agreed to this and asked us to start focusing on this by first performing a literature review on all the components we'd require and the working of the project and also to start working on this project.

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• I first began with the look of the Power circuitry which contains our main Tapping Transformer. The tapping is provided at 231V, 225V, 220V, 214V, 209V and 0V. Furthermore, I decided to combine BTA16 Triacs. I also made a decision to create a snubber circuit using 100 resistor and a 104pF capacitor.
• I decided to use the Triac instead of the SCR because a triac operates just as as the SCR however it operates in both frontward and reverse directions. Also, I had developed to ensure the TRIAC will turn off correctly at the end of each half-cycle of the AC electricity. And due to this reason I used the snubber circuit to assist in the turning off and on. I used a MOC 3021 to assist with this.

Circuitry Diagram

• The following are the components I used because of this job:

  - I used the AT80S8252 Microcontroller or the 89C52 which really is a high performance CMOS 8bit microcomputer of kinds.

  - ADC 0804 Analog to Digital Controller which feeds the type to the microcontroller. I used a step down transformer to provide samples to the ADC of the strain.

  - No Crossing Detector to provide the required pulses for the AND reasoning combined with the multiplexer.

  - A Multiplexer or Mux is a tool that selects one of the analog or digital source alerts and forwards the picked input into a single series.

  In my task, the Interlocking device is attained by using Multiplexer. Thus, at any instant of energy, no two triacs would be in their ON STATE. That is especially important and useful in the event the logic of microcontroller fails.

  - I used a Water Crystal Screen (LCD) to display the output voltage that might be across the insert side.

  - I used an Optocoupler MOC 3021 to copy signals between varying elements of any circuit.

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The pursuing is the way in which of the working of the project by using a block diagram:

• The stop diagram shows the essential strategy, as to how the Weight Tap Changer will work automatically. I used TRIACs as the turning devices.
• I ensured that the The transformer has five tappings at the voltage level. Each one of these tappings is linked to the one of the main terminals of the TIRAC. The next main terminals of all the five TRIACS have been shorted. So at any moment when the TRIAC has been started up there is only one conducting way to the strain.
• I used a step down transformer to step down the voltage level to instrumentation levels such that it can be utilized in the control circuitry. As the voltage increases or decreases with respect to the nature of the strain the voltage at the primary of the step down transformer varies, resulting in an equivalent variant at the extra side.
• I then experienced to make certain that sampled AC voltage is rectified for an almost easy DC value. This DC voltage is then fed to the analog to digital converter, gives a digital end result that may be realized by the microcontroller. The ADC outcome is given to the microcontroller which have been already designed to compare this incoming value to a couple of predefined values and send a high signal on one of its dock bits. The outcome of the microcontroller is given to a multiplexer. It really is designed to ensure that at any moment, even if the logic fails there is only 1 conduction path to the strain. I. e. only 1 TRIAC is started up at any occasion with time.
• I also used the zero crossing detector in order to find the occasion when the AC voltage crosses the zero amplitude mark. The output of the zero crossing detector is at the proper execution a pulse generated every half pattern.
• I then given the productivity of the zero crossing detector and the multiplexer to the AND reasoning as shown in the diagram. Each and every time the zero crossing detector gives an output, a pulse is made at the outcome of the AND logic
• This result of the AND logic is actually our trigger sign for the switching devices i. e. the TRIACs yet, in order to isolate the control and high voltage circuitry and to put into action DC triggering on the TRIACs operating at AC voltages the Optocouplers have been contained. So essentially the Optocouplers are just there to provide isolation.

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The pursuing are simulation results I obtained:

When input is 220v, the Triac on Faucet 3 is on.

When the suggestions is 225v, the Triac on Faucet 2 is on.

1. Summary

CE 3. 10

I effectively completed the project titled "Design and Simulation of Automatic Load Tap Changer" along with my team partner. I learned developing a circuit panel and how all the various electrical components talk to each other in this project. I learned how important the strain Touch Changer is for any power grid and how useful it is over the Mechanical type Weight type changer.

By successfully doing this task, I could improve my written, dental and interpersonal skills.