A power flow calculation method considering the thermal characteristics of XLPE insulated cables

Abstract

The invention discloses a load flow calculation method of an electrical network in consideration of thermal property of a cross-linked polyethylene insulated cable. The load flow calculation method comprises following steps: establishing an equivalent circuit of the cable corresponding to a selected cable; describing the thermal equilibrium rule of the cable by a differential equation set based on the equivalent circuit; further introducing the differential equation set in order to form an electrothermal coupling load flow model of the thermal property of the cable; converting differential equations of the differential equation set into algebraic equations in consideration of load flow calculation method of the thermal property of the cable and then solving in order to obtain an implicit trapezoidal difference result by utilization of a Newton's method; combining the above result with a difference result of a heat balance equation of an overhead transmission line in order to form an algebraic form of the differential equation set in the time section; obtaining a correction equation of the Newton's method in consideration of a load flow model for the thermal property of the cable after algebraization; and solving the correction equation of the Newton's method in order to obtain the changing trajectory for running states of the electrical network containing cable temperature.

Description

technical field [0001] The invention relates to a power flow calculation method considering the thermal characteristics of cross-linked polyethylene insulated cables. Background technique [0002] Compared with overhead transmission lines, cable transmission has the characteristics of environmental protection, beauty, and high reliability of power supply, and has become one of the main methods of urban power grids and cross-sea power transmission. Among them, cross-linked polyethylene (XLPE) insulated high-voltage cables are widely used due to their advantages of light weight, relatively simple manufacturing and accessory structures, and high operating temperature. [0003] The essence of cable load capacity lies in thermal limitation. Temperature is an important state quantity that characterizes its load status. In order to accurately grasp the operating temperature of cables, cable online monitoring technology has been rapidly developed and applied since the 1990s. Current...

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Problems solved by technology

[0004] In terms of cable lines, the existing literature mainly focuses on the research on the thermal characteristics of cables, and establishes the XLPE cable heat balance equation, and some literatures illustrate the advantages that can be brought by making full use of cable thermal inertia in power grid operation analysis and dispatch control through simple examples. Remarkable results, but the power flow calculation technology that takes into account the thermal characteristics of cables has not been reported

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