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Central Operation and Control of Power Systems
Published in George Kusic, Computer-Aided Power Systems Analysis, 2018
Usually, neighboring power companies are interconnected by one or more transmission lines called tie lines, as depicted graphically in Figure 1.7. The electrical areas shown in Figure 1.7 are separate power systems under the control of an AGC in a central digital computer. The boundaries of an area are the points on the tie lines where a utility’s ownership, maintenance, and loss accounting ends and those of its neighbors begin. There are very few isolated power systems that are not connected to neighbors by means of tie lines. The power systems employ tie lines for the following reasons: Tie lines allow a local or “pool” exchange and sale of power between the power companies on a predetermined schedule. Tie lines allow areas experiencing disturbances to draw on other areas for help.Tie lines provide a long-distance transmission line for the sale and transfer of power (e.g., on an interstate or international basis).
Design of two degree of freedom-internal model control configuration for load frequency control using model approximation
Published in International Journal of Modelling and Simulation, 2019
Bheem Sonker, Deepak Kumar, Paulson Samuel
In general, the load frequency control (LFC) problem is the control of the real power output of generating units in response to the changes in the system frequency and the tie-line power interchange within specified limits [1]. The transmission lines, which connect the generation, transmission, and distribution systems, are called tie lines. During the operation of power system, the role of load frequency control is essential if the fluctuations occur in tie-line power interchange [2] due to random changes in load demand and external disturbance. Therefore, the power system should be stable and robust enough for specified voltage levels such that it could sustain the external disturbance and parameter uncertainties in the case of any transient disturbances.
RETRACTED ARTICLE: Power sharing scheme in interconnected DC microgrids – A new approach
Published in International Journal of Ambient Energy, 2022
Jayavani Lagudu, S. Sathya Narayana, Ganesh Vulasala
The objectives of interconnected ring dc microgrid operation are to control the parallel converters involved to interface DG units and to achieve proportional load sharing and voltage regulation. The amount of tie-line power flow depends upon ±5% change in the dc bus voltages of interconnected lines. The rating of tie-line is based upon the maximum temperature of the conductor at which the line designed to operate. A tie-line can withstand 115% of overload for 10 min without exceeding design temperatures. The tie-line impedance value calculated by (20). Where ρ is resistivity of tie-line cable, l is length of tie-line, A is cross section area of tie-line. The complete list of parameters is given below.
Wind Driven Optimization Algorithm Application to Load Frequency Control in Interconnected Power Systems Considering GRC and GDB Nonlinearities
Published in Electric Power Components and Systems, 2018
Hassan Haes Alhelou, Mohamad Esmail Hamedani Golshan, Masoud Hajiakbari Fini
Interconnected power system has some areas connected together via tie lines. In these power systems, tuning load frequency controllers is harder than isolated power systems. In the interconnected power system, the demand of each area can be supplied by the generating units within that area or by the transmitted power from other areas. The transmission power capability of the tie-lines between the areas is limited so, they should not be overloaded. The power flow through tie line between area and area j can be expressed by (5).