NONCOMMERCIAL JOINT STOCK COMPANY
ALMATY UNIVERSITY OF POWER ENGINEERING AND TELECOMMUNICATIONS
Department of “Power plants and electrical power engineering systems”
Calculation graphical work №3
On the discipline “Power station and substation”
Theme: Calculation of short-circuit currents and selection of switching equipment
Speciality: 5B071800 - Electrical Power Engineering
Done by: Shaimuradov E. Group: EPEe-15-10 Student card: 28
Checked by: associate professor Ospanova G. S.
_________ ___________ “___” __________ 2017
(score) (signature) (day) (month)
Content
1 Purpose and objectives of CGW 3
2 Initial data 3
3 Short-circuit currents calculation 5
4 Selection of the switching equipment 8
5 Drawing up a simplified schematic diagram of the CHPP 9
Conclusion 10
List of references 11
Conclusion
This calculation and graphical work № 3 is a continuation of CGW № 1 and CGW № 2 in the discipline "Electric stations and substations".
When performing the calculation and graphic work № 3 for the discipline "Electric stations and substations" the student learns methods of calculating the short-circuit current for selecting and checking the parameters of electrical equipment, electrical apparatus and current-carrying parts of electrical installations. In this case, the main purpose of the calculation is to determine the periodic component of the short-circuit current and the short-circuit shock current for the heaviest operation of electrical installations. Allowance for the aperiodic component is made approximately, assuming that it has a maximum value in the phase under consideration. Particular attention should be paid to:
- the calculation scheme and the substitution scheme;
- determine the resistance of the elements of the circuit and bring them to the basic conditions;
- determination of short-circuit currents taking into account the results from electric power sources;
- selection of high-voltage switches and disconnectors;
- implementation of the circuit diagram of the CHP taking into account switches and disconnectors.
1 Purpose and objectives of cgw
The purpose of CGW # 3 is to consolidate theoretical knowledge and develop students' independence in solving specific problems, acquire practical skills in calculating short-circuit currents in electrical installations, the selection of switching devices and the construction of a simplified schematic diagram of the electrical connections of the CHP. This calculation and graphic work No. 3 is a continuation of CGW # 1,2 in the discipline "Electric stations and substations".
Objectives of CGW:
1) to compile a design scheme and a substitution scheme according to the selected structural scheme from CGW # 2;
2) from the head of CGW #3, to obtain a short-circuit point in the SGLV, or in SGMV, or in the SGHV of power plants;
3) determine the resistance of the elements of the circuit and bring them to the basic conditions;
4) transforming the replacement circuit, determine the resulting resistances;
5) determine the initial value of the periodic component of the short-circuit current, then the aperiodic component of the short-circuit current, the shock current and the short-circuit current for a given time;
6) to make a choice of switching devices (high-voltage switches and disconnectors);
7) to compile a simplified schematic diagram of the electrical connections of the CHPP