Urgency
Because of the financial condition worsening it is observed the worsening of energy equipment condition at the Ukrainian enterprises for the last decades. Majority of enterprises don’t have possibility to modernize the factory, therefore they are forced to utilize outmoded equipment, particularly it concerns the reactive power compensation (RPC). Per RPC out of all possible methods of energy-saving falls near 80% of probable energy saving in electrical networks.
Reactive power transfer results in load growth, overloads of the power lines with reactive currents, that results in active power loss increase when electric power is transferred to consumers. Reactive power overloads electric power plants, that results in frequency drop in system. Frequency drop in turn result in consumers emergency outage. Reactive power appearance in network promotes equipment overheating and cable lines overheating. It results in service life decrease.
It follows from the mentioned above, that reactive power compensation at the industrial enterprises is necessary, actual and economically sound.
Scope of work.
Theoretical analysis.
For the industrial enterprises, which in majority of cases have multibranching electrical network, it is necessary to decide question of the optimum termination point of capacitors banks: to 6 – 10 buses of main step – down substation of industrial enterprise, to distribution points or on the 0,4 kV side of transformer shopfloor substation. Also it is necessary to check the capability and reasonability of utilization of high-voltage synchronous motors (SM), which are connected to load centers. Optimum alternative can be selected on the basis of techno – economic calculation. Possible decrease TSS powers, cable lines sections, electric loss in lines and transformers, cost of installed capacitor banks affect the capacitors banks placement location, potential utilization of SM for reactive power generation. Thus, while choosing the optimum we have to take into account quantity of factors. Account is carrying out on the discounted costs, which are function of several variables: capacitor banks powers, connected to all load centers; SM powers, which can be used for reactive power compensation.
The task comes to the search of minimum of the function of the discounted costs. Necessity of stepped variation stocktaking of TSS power, cable line sections makes difficulties with discounted costs partial derivatives of every variable.
Optimal value of the generated reactive power of SM has to be defined by techno – economic calculations taking into account of active load of SM and reactive load of consumer network, thermal condition and active power loss. Criterion for defining the reasonability of utilization of synchronous motors for RPC is discounted costs, which account cost of additional power loss in SM because of RP generation ΔРSM and also the cost of capacitor banks, active power loss in capacitors banks, operation costs. The possibility of utilization SM for RPC has to be checked according to conditions of rotor windings heating and stator windings heating too.