Residential and industrial buildings with large territorial dimensions, have mainly radial power supply schemes, which feed a large number of small and medium capacity 0.4 kV induction motors. For their power supply copper or aluminum cables of small cross-section (with high active resistance) are used. Calculations of electricity losses in such lines show significant values. In order to reduce active power losses in 0.4 kV cable lines, the optimization problem of minimizing active power losses in the radial power supply circuit is solved by optimal distribution of reactive power of a given value between compensating devices. The single-line scheme of power supply of a group of pumps of technological installation of petrochemical production is considered, the mathematical model of the optimization problem on criterion of minimum of active losses in power lines from reactive power flow is made, which limitations are presented as a system of linear algebraic equations. Results of distribution of optimum values of reactive power between compensating devices of asynchronous motors at maintenance of the set tg φ are received. The quantitative estimation of active power loss reduction in power lines at use of capacitor units, which reactive power is optimally distributed, is given.
У статті проаналізовані методи оцінки плавності руху автомобільної техніки. Запропонований метод визначення плавності руху автомобіля частотним методом. Динамічна модель вільних коливань автомобіля дозволяє визначити чотири частоти власних коливань при його повній та спорядженій масі. Нижчу частоту власних коливань рекомендується використати для оцінки плавності руху бронеавтомобіля. Розрахунки виконані для бронеавтомобіля БРДМ-2Л1. Результати випробувань підтвердили дієвість запропонованого методу.
We propose a solution for optimization problem of minimizing active power losses for radial power supply scheme by optimal distribution of a given amount of reactive power between the compensating devices. We considered a single-line power supply scheme for a group of pumps of technological installation at a chemical plant. A mathematical model of the optimization problem is compiled by the criterion of active losses minimum in power lines depending on the reactive power flow. We obtained the distribution of optimal values of reactive power between the compensating devices of asynchronous motors for the specified tg φ. Quantitative and cost estimations are given for reducing the active power losses in power transmission lines when using capacitor plants, the reactive power of which is optimally distributed. We investigated the influence of starting currents on a circuit when asynchronous motor and capacitor installation are simultaneously turned on. We established the absence of an additional dynamic load on the supply lines.
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