Electrical Power System Analysis PDF

2/20/2024 Course Learning Out come -2 Analyze power system using single line and reactance diagrams Analyze power system using single line diagram from the information's provided. Designing the reactance diagrams for a large power system with...

2/20/2024 Course Learning Out come -2 Analyze power system using single line and reactance diagrams Analyze power system using single line diagram from the information's provided. Designing the reactance diagrams for a large power system with Alternator, load, long transmission lines and transformers. Adding shunt compensation and series compensation to the reactance diagram circuit. Computation of per unit reactance values Reference : Sivanagaraju, S., Reddy, Rami B. V..; Electrical Power System Analysis University science press One Line Diagram ( Single line Diagram): The complete diagram of a power system representing all the three phases becomes too complicated for a system of practical size. Practically a power system represent by means of simple symbols for each components resulting is called one line diagram or single line diagram. One line diagram of a power system shows the main connections arrangements of components. The purpose of the one line diagrams is to supply in short form, the significant information about the power system.. https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_138 1  2/20/2024 Symbols used in one line diagram: S.No. Equipment Symbol 1 Machine (generator or motor) 2 Two winding transformer 3 Circuit breaker 4 5 6 https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_138 Example of Single line diagram: The system has two generators and are grounded through a reactor, that are connected to a bus and through a step-up transformer to a transmission line. Another generator, grounded through a reactor, is connected to a bus and through a transformer to the other end of the transmission line. A load is connected to each bus. https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_139 2  2/20/2024 Equivalent circuit for various components: https://search.ebscohost.com/login.aspx?direct=true&db=e065sww&AN=1820919&site=eds-live&ebv=EB&ppid=pp_172 Impedance diagram: In order to calculate the performance of a system under balanced conditions, the one-line diagram is used to draw the per-phase equivalent circuit of the system. Various system components are represented by per phase equivalent circuit and resulting diagram is known as per-phase impedance diagram (or Simply impedance diagram). Impedance diagram is used for load flow studies https://search.ebscohost.com/login.aspx?direct=true&db=e065sww&AN=1820919&site=eds-live&ebv=EB&ppid=pp_186 3  2/20/2024 Assumptions are made in obtaining the impedance diagram: Generators & motors are represented by voltage sources with series resistance and inductive reactance (R+X) Loads (L) are represented by series resistance & reactance (R+X)(loads assumed passive) (not involving rotating machines (static load)) The single phase transformer are represented by their impedances (LV/HV side ).The magnetizing reactance's of transformers are negligible  Short transmission lines are represented by their series impedances Medium and long lines are represented by their π circuit models Neutral grounding impedances are neglected (no current flowing during balanced condition) https://search.ebscohost.com/login.aspx?direct=true&db=e065sww&AN=1820919&site=eds-live&ebv=EB&ppid=pp_172 Impedance diagram Drawn From the single diagram: https://search.ebscohost.com/login.aspx?direct=true&db=e065sww&AN=1820919&site=eds-live&ebv=EB&ppid=pp_186 4  2/20/2024 Reactance Diagram Of Power System: The equivalent circuit of a given power system in which each component of the system is represented by its own reactance is known as reactance diagram. The reactance diagram can be obtained form impedance diagram if all the resistive components are neglected It used for fault calculation Assumptions :  Neglect the resistance of all the equipment's.  Neglect the charging admittance of transmission lines. Neglect the shunt branches in the equivalents circuit of transformers.  Neglect the static loads. https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_141 https://search.ebscohost.com/login.aspx?direct=true&db=e065sww&AN=1820919&site=eds-live&ebv=EB&ppid=pp_187 5  2/20/2024 Per Unit Quantities: The components or various sections of power system may operate at different voltage and power levels. It will be convenient for analysis of power system if the voltage, power, current and impedance ratings of components of power system are expressed with reference to a common value called base value. Hence for analysis purpose a base value is chosen for voltage, power, current and impedance. Then all the voltage, power, current and impedance ratings of the components are expressed as a per unit value of the base value. https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_139 https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_139 6  2/20/2024 https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_139 https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_139 7  2/20/2024 https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_141 where Vp and Vs are primary & secondary voltages of the transformer. https://ebookcentral.proquest.com/lib/momp/reader.action?docID=3382455&ppg=27 8  2/20/2024 https://ebookcentral.proquest.com/lib/momp/reader.action?docID=3382455&ppg=27 Advantages of per unit computations: p.u. values provide more meaningful information. p.u. values in terms of phase quantities or line values are same. The impedances of machines are specified by the manufacturers in terms of p.u. values. The p.u. impedance referred to either primary or secondary sides of transformer is same. The p.u. values being in the order of unity or less can be easily handled with a digital computer. No effect on transformer connections either in star or delta. https://search.ebscohost.com/login.aspx?direct=true&db=e000xww&AN=2228663&site=eds-live&ebv=EB&ppid=pp_141 9