Lecture 2 - Introduction to Power System PDF

Cairo University Faculty of Engineering Electrical Power Engineering (EPE) Principles of Energy Conversion (EPEG102) Lecture 2 – Introduction to Power System Dr. Ahmed M. Zobaa Contact email: [email protected]  Power System Gene...

Cairo University Faculty of Engineering Electrical Power Engineering (EPE) Principles of Energy Conversion (EPEG102) Lecture 2 – Introduction to Power System Dr. Ahmed M. Zobaa Contact email: [email protected]  Power System Generation Transmission Distribution Load  Power System Steam 30.6% Generation Transmission Distribution Load Thermal Gas 4.8% Combined Hydro 4.8% 54.3% Cycle Generation Wind 2.7% Photovoltaic Solar 2.8% Concentrated Solar Power Nuclear Geothermal  Power System Thermal Stations (Steam) Generation Transmission Distribution Load  Power System Thermal Stations (Steam) Generation Transmission Distribution Load  Power System Thermal Stations (Steam) Generation Transmission Distribution Load  Power System Thermal Stations (Steam) Generation Transmission Distribution Load  Power System Thermal Stations (Gas) Generation Transmission Distribution Load  Power System Thermal Stations (Gas) Generation Transmission Distribution Load  Power System Thermal Stations (Gas) Generation Transmission Distribution Load  Power System Thermal Stations (Combined Cycle) Generation Transmission Distribution Load  Power System Thermal Stations (Combined Cycle) Generation Transmission Distribution Load  Power System Hydro Stations Generation Transmission Distribution Load  Power System Wind Stations Generation Transmission Distribution Load  Power System Wind Stations Generation Transmission Distribution Load  Power System Solar PV Stations Generation Transmission Distribution Load  Power System CSP Stations (Solar Troughs) Generation Transmission Distribution Load  Power System CSP Stations (Solar Thermal Dishes) Generation Transmission Distribution Load  Power System CSP Stations (Solar Power Tower) Generation Transmission Distribution Load  Power System Nuclear Stations Generation Transmission Distribution Load  Power System Nuclear Stations Generation Transmission Distribution Load  Power System Geothermal Stations Generation Transmission Distribution Load  Power System Transmission Generation Transmission Distribution Load Why do we step up the voltage during transmission? ▪ Most of the generation is done between 11 – 25 kV. ▪ This voltage is not suitable for transmission over long distances. ▪ The transmission is usually utilizing 220 or even 500 kV. 𝑃∝𝑉 𝐼 ▪ Lower current. ▪ Lower voltage drop. ▪ Lower cables or TL C.S.A. 𝑃∝𝑉 𝐼 ▪ Lower power losses. ▪ Higher transmission efficiency.  Power System Transmission Generation Transmission Distribution Load ▪ The underground cables are usually 6-10 times more expensive than Overhead Transmission Lines (OHTLs). ▪ Underground cables are usually used inside cities, where the use of OHTLs is prevented due to health issues and very costly right of way.  Power System Transmission Generation Transmission Distribution Load  Power System Transmission Generation Transmission Distribution Load Why don’t we increase the voltage to infinity? The breakdown voltage of porcelain insulators can reach up to 100 kV/cm. Multiple insulator pins are used in series to insulate the transmission voltage levels.  Power System Transmission Generation Transmission Distribution Load Why don’t we increase the voltage to infinity? The higher the transmission voltage: Higher transformers (step up/down) cost. Higher insulation cost. Higher tower cost.  Power System Distribution Generation Transmissio n Distribution Load Substation Switch yard Substation step down transformer  Power System Distribution Generation Transmissio n Distribution Load 11 kV overhead TL 11 kV three-phase overhead pole-mounted distribution transformer Isolated vs Interconnected Power Systems 2 x 100 2 x 50 MW is 2 x 50 more expensive than 1 x 100 1 x 100 Backup1 x 100 MW Backup1 x 50 Advantages of interconnected system: Lower initial cost Lower cold reserve cost Better reliability Lower power losses Lower voltage drop