Transient Processes
Description: General information about electromagnetic transients Basic concepts. Assumptions made in the study of electromagnetic transients (MPP). Transients (PP) when forcing the excitation of synchronous generators, quenching the magnetic field of generators, when switching transformers with an open secondary winding into the electrical network and during short circuits (short circuit).
Amount of credits: 5
Пререквизиты:
- Theoretical Foundations of Electrical Engineering II
Course Workload:
| Types of classes | hours |
|---|---|
| Lectures | 15 |
| Practical works | 30 |
| Laboratory works | |
| SAWTG (Student Autonomous Work under Teacher Guidance) | 30 |
| SAW (Student autonomous work) | 75 |
| Course Paper | |
| Form of final control | Exam |
| Final assessment method | Written exam |
Component: Component by selection
Cycle: Base disciplines
Goal
- study of methods for calculating various electromagnetic transients, especially for symmetric and asymmetric short circuits in electrical installations.
Objective
- The objectives of the discipline are: • to give students an idea of the nature of transients when forcing the excitation of synchronous machines, quenching their magnetic field and switching on an unloaded transformer for a short circuit; • to instill the skills of calculating three-phase and asymmetric short circuits by various methods; • to give an idea of the influence of the damping circuits of synchronous machines and their excitation systems on the nature of the transient process during short circuits.
Learning outcome: knowledge and understanding
- Know the basic patterns and mathematical description of transients
Learning outcome: applying knowledge and understanding
- Be able to solve typical tasks and perform calculations of transients in electric power systems
Learning outcome: formation of judgments
- Be able to analyze and reasonably interpret the results of calculations of transient processes of electric power systems
Learning outcome: communicative abilities
- Have the ability to solve a complex problem of the electric power industry in a team based on the knowledge of transients
Learning outcome: learning skills or learning abilities
- Be ready to constantly master new methods of calculating transients using modern computing tools
Teaching methods
When conducting training sessions, it is planned to use the following educational technologies: - In the conditions of credit technology of training, classes should be conducted mainly in active and creative forms. Among the effective pedagogical methods and technologies that contribute to the involvement of students in the search and management of knowledge, the acquisition of experience in solving problems independently, it should be highlighted: - technology of problem- and project-oriented learning; - technologies of educational and research activities; - communication technologies (discussion, press conference, brainstorming, educational debates and others active forms and methods); - case study method (situation analysis); - game technologies, in which students participate in business, role-playing, simulation games; - information and communication (including distance education) technologies.
Assessment of the student's knowledge
Teacher oversees various tasks related to ongoing assessment and determines students' current performance twice during each academic period. Ratings 1 and 2 are formulated based on the outcomes of this ongoing assessment. The student's learning achievements are assessed using a 100-point scale, and the final grades P1 and P2 are calculated as the average of their ongoing performance evaluations. The teacher evaluates the student's work throughout the academic period in alignment with the assignment submission schedule for the discipline. The assessment system may incorporate a mix of written and oral, group and individual formats.
| Period | Type of task | Total |
|---|---|---|
| 1 rating | 1 IWS. Basic concepts. Assumptions made in the study of electromagnetic transients (MPP). Transients (PP) when forcing the excitation of synchronous generators, quenching the magnetic field of generators, when switching transformers with an open secondary winding into the electrical network and during short circuits (short circuit). | 0-100 |
| 1 Practical work. Calculation of three-phase symmetric short circuit. Calculation of basic conditions | ||
| Oral interview. Basic concepts. Assumptions made in the study of electromagnetic transients (MPP). Transients (PP) when forcing the excitation of synchronous generators, quenching the magnetic field of generators, when switching transformers with an open secondary winding into the electrical network and during short circuits (short circuit). | ||
| 2 IWS.The initial differential equation of PP and its solution. The concept of short circuit shock current. Impact coefficient and methods of its determination. Features of PP at short circuit in a branched chain. | ||
| 2 Practical work. Determination of EMF, resistance of the replacement circuit | ||
| 3 IWS.Mathematical model of a synchronous machine (SEE). Flow couplings, proper and mutual inductances SEE. Linear transformations of the CM equations to the rotor axes. The concept of the image vector. The Park-Gorev equations. | ||
| Oral interview. Equations of electromagnetic transients in a synchronous machine | ||
| 4 IWS. Calculation of the initial effective value of the periodic component of the short-circuit current | ||
| 4 Practical work. Drawing up substitution schemes when expressing their elements in systems of named and relative units. | ||
| Lecture notes | ||
| Testing | ||
| 2 rating | 5 IWS. Change in time of the current value of the short-circuit current from the synchronous machine | 0-100 |
| 5 Practical work. Calculation of symmetrical short-circuit currents | ||
| Oral survey. Practical methods for calculating the periodic component of the short circuit current | ||
| 6 IWS. Determination of the distance of the short circuit point from the electric machine. Calculation of the PS current at remote short circuits. Calculation using the method of typical curves. Calculation using straightened characteristics. | ||
| 6 Practical work Calculation of asymmetric short circuits. Direct sequence.The reverse sequence. Zero sequence | ||
| 7 IWS. Advantages of the method of symmetric components. Determination of parameters of the reverse sequence of CM and motors. Determination of the parameters of the zero sequence of transformers, autotransformers and overhead power lines (transmission lines). The effect of lightning protection cables and parallel circuits on the resistance of the zero sequence of power lines. | ||
| 7 practical work with vector diagrams | ||
| Oral interview. Asymmetric short circuit current. | ||
| Lecture notes | ||
| Testing | ||
| 8 IWS. Initial equations. Two-phase short circuit. Single-phase short circuit. Two-phase short circuit to the ground. Calculation of PP with asymmetric short circuits by different methods. The ratio of short-circuit currents of different types during short circuits at the same point. | ||
| Total control | Exam, Course Paper | 0-100 |
The evaluating policy of learning outcomes by work type
| Type of task | 90-100 | 70-89 | 50-69 | 0-49 |
|---|---|---|---|---|
| Excellent | Good | Satisfactory | Unsatisfactory |
Evaluation form
The student's final grade in the course is calculated on a 100 point grading scale, it includes:
- 40% of the examination result;
- 60% of current control result.
The final grade is calculated by the formula:
| FG = 0,6 | MT1+MT2 | +0,4E |
| 2 |
Where Midterm 1, Midterm 2are digital equivalents of the grades of Midterm 1 and 2;
E is a digital equivalent of the exam grade.
Final alphabetical grade and its equivalent in points:
The letter grading system for students' academic achievements, corresponding to the numerical equivalent on a four-point scale:
| Alphabetical grade | Numerical value | Points (%) | Traditional grade |
|---|---|---|---|
| A | 4.0 | 95-100 | Excellent |
| A- | 3.67 | 90-94 | |
| B+ | 3.33 | 85-89 | Good |
| B | 3.0 | 80-84 | |
| B- | 2.67 | 75-79 | |
| C+ | 2.33 | 70-74 | |
| C | 2.0 | 65-69 | Satisfactory |
| C- | 1.67 | 60-64 | |
| D+ | 1.33 | 55-59 | |
| D | 1.0 | 50-54 | |
| FX | 0.5 | 25-49 | Unsatisfactory |
| F | 0 | 0-24 |
Topics of lectures
- 1 lecture General information about electromagnetic transients
- Lecture 2 Transient process with a three-phase short circuit in an electrical circuit connected to a sinusoidal voltage source
- Lecture 3 Equations of electromagnetic transients in a synchronous machine
- Lecture 4 Calculation of the initial effective value of the periodic component of the short circuit current
- Lecture 5 Change in time of the current value of the short circuit current from the synchronous machine
- Lecture 6 Practical methods for calculating the periodic component of the short circuit current
- Lecture 7 Features of calculations of asymmetric short circuits
- Lecture 8 Calculations of asymmetric short circuits
Key reading
- 1. Transients in electric power systems: textbook for universities / I.P. Kryuchkov, V.A. Starshinov, Yu.P. Gusev, M.V. Piratorov; edited by I.P. Kryuchkov. – M.: Publishing House of MEI, 2012. 2. Short circuits and asymmetric modes of electrical installations: a textbook for university students / I.P. Kryuchkov, V.A. Starshinov, Yu.P. Gusev, M.V. Piratorov. – M.: Publishing House of MEI, 2018. 3. Calculation of short circuits and choice of electrical equipment: a textbook for higher education students. textbook. institutions / I.P. Kryuchkov, B.N. Neklepaev, V.A. Starshinov, etc.; edited by I.P. Kryuchkov and V.A. Starshinov. – 3rd ed., ster. – M.: Publishing Center "Academy", 2016. 4. Kryuchkov I.P. Electromagnetic transients in electric power systems. Textbook for universities. – M.: Publishing House of the MEI, 2012. 5. Kryuchkov I.P., Kozinova M.A. Three-phase short circuits. Calculation tasks: methodical manual. – M.: Publishing House of the MEI, 2014. 6. Kryuchkov I.P., Volkova N.N. Asymmetric short circuits. 2016
