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Basics of Power Systems

Basics of Power Systems 22
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JuliyaMadenta,Philippines,Researcher
Published Date:15-07-2017
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Topic 1: Basics of Power Systems ECE 5332: Communications and Control for Smart Spring 2012 A.H. Mohsenian‐Rad (U of T) Networking and Distributed Systems 1Power Systems •The Four Main Elements in Power Systems: Power Production / Generation Power Transmission Power Distribution Power Consumption / Load  •Of course, we also need monitoring and control systems. Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 2Power Systems •Power Production: Different Types: Traditional Renewable Capacity, Cost, Carbon Emission Step‐up Transformers Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 3Power Systems •Power Transmission: High Voltage (HV) Transmission Lines Several Hundred Miles Switching Stations  Transformers Circuit Breakers Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 4Power Systems •The Power Transmission Grid in the United States: www.geni.org Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 5Power Systems •Major Inter‐connections in the United States: www.geni.org Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 6Power Systems •Power Distribution: Medium Voltage (MV) Transmission Lines ( 50 kV) Power Deliver to Load Locations Interface with Consumers / Metering Distribution Sub‐stations Step‐Down Transformers Distribution Transformers Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 7Power Systems •Power Consumption: Industrial Commercial Residential Demand Response Controllable Load Non‐Controllable Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 8Power Systems Generation Load Transmission Distribution Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 9Power Systems •Power System Control: Data Collection: Sensors, PMUs, etc. Decision Making: Controllers Actuators: Circuit Breakers, etc. Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 10Power Grid Graph Representation Nodes: Buses Links: Transmission Lines Generator Load Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 11Power Grid Graph Representation Nodes: Buses Links: Transmission Lines Buses (Voltage) Generator Load Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 12Power Grid Graph Representation Nodes: Buses Links: Transmission Lines Generator Load Transmission Lines (Power Flow, Loss) Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 13Power Grid Graph Representation Nodes: Buses Links: Transmission Lines Generator Load Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 14 ConsumersPower Grid Graph Representation Nodes: Buses Links: Transmission Lines Generator 10 MW 3 MW Load 7 MW Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 15Transmission Line Admittance •Admittance y is defined as the inverse of impedance z: z = r + j x                   (r: Resistance, x: Reactance) y = g + j b(g: Conductance, b: Susceptance) y = 1 / z Parameter g is usually positive Parameter b:  Positive: Capacitor Negative: Inductor Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 16Transmission Line Admittance •For the transmission line connecting bus ito bus k: Addmitance: y ik Example: y = 1 –j 4   (per unit) ik Note that, y is denoted by y and indicates: ii i  Susceptance for any shunt element (capacitor) to ground at bus i.  Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 17Y-Bus Matrix • We define: Y =  Y  where bus ij N Diagonal Elements: Y y y ii i ik k1,ki Off‐diagonal Elements:  Yy ij ij Note that Y matrix depends on the power grid topology  bas and the admittance of all transmission lines. N is the number of busses in the grid. Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 18Y-Bus Matrix •Example: For a grid with 4‐buses, we have: y y y y y y y  1 12 13 14 12 13 14   y y y y y y y 21 2 21 23 24 23 24  Y bus   y y y y y y y 31 32 3 31 32 34 34   y y y y y y y 41 42 43 4 41 42 43  •After separating the real and imaginary parts: YG jB bus Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 19Bus Voltage •Let V denote the voltage at bus i: i •Note that, V is a phasor, with magnitudeand angle.  i V V i i i •In most operating scenarios we have: V V i j i j Dr. Hamed Mohsenian-Rad Communications and Control in Smart Grid Texas Tech University 20