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Nagy, Sayed A.
- Power Quality Enhancement for Smart Distribution System Using Superconducting Magnetic Energy Storage Unit
Authors
1 Ministry of Electricity and Energy, EG
2 Department of Electrical Power Engineering, University of AlAzhar, EG
3 Helwan University, EG
4 inistry of Electricity and Energy, EG
Source
Programmable Device Circuits and Systems, Vol 7, No 9 (2015), Pagination: 276-279Abstract
This paper has developed the superconducting magnetic energy storage (SMES) unit to improve the power quality and transient stability behaviour of a large industry facility in a smart grid. The connected transmission line with the utility has tripping system by using the under frequency relays, this tripping system has been modified to prevent cascaded collapse of the power system in case of occurrence of utility power system external fault. Fault simulated has been performed to explore the accuracy of the transient stability analysis. To improve the power quality, SMES unit has been installed in the smart distributed system. The sensitivity analysis of SMES unit is applied to achieve better system responses. SMES unit with frequency changing as feedback signal to active power control is also used to improve the electric power fluctuation and help the utility in maximum demand times. Also improve the power quality of the system and reduce the economic losses of the facility.
Keywords
Smart Grid, Superconducting Magnetic Energy Storage, Transient Stability, Power Quality.
- Using Logic Controls in Cascaded Events Prevention for Pilot Distance Relay Zone Three
Authors
1 Ministry of Electricity and Energy, EG
2 Department of Electrical Power Engineering, University of AlAzhar, EG
3 Electrical Power and Machine Department, Helwan University, EG
Source
Programmable Device Circuits and Systems, Vol 7, No 6 (2015), Pagination: 178-184Abstract
This paper presents a new method to prevent cascaded events of pilot distance relays caused by zone 3 elements in case of heavy loaded transmission line or during load encroachment by using logic controls. Undesired operation of distance relay may be leaded to activation of another distance relays and cascaded to partial or total blackout in the end. A proposed adaptive distance protective gives a new concept to distinguish between faults and heavy loaded transmission line depending on analyzing system parameters and data transfer between distance devices, and also secures time to make repaired action like load shedding. Logic controls are used to insure the decision to trip or not, through observing the system parameters and compare its values with setting already input to the system. When the distance relay pickup and the logic controls find the system is healthy, that means the resulted pickup came from transmission line overload not from actual fault. Consequently the trip signal is blocked and protects the system from cascaded mal-operation, or send load shedding signal to reduce the current flow through this line.