Облік електроенергії при несинуcоїдальних і несиметричних режимах у мережах електропостачання міст

Abstract

Розглянуто проблему порушення симетрії навантаження та виникнення несинусоїдальних режимів у трифазних системах електропостачання мереж міст з нелінійними параметрами встановлених освітлювальних установок та, як наслідок, завищення при наявності несиметрії та нелінійності навантажень оплати за спожиту електроенергію. Доведено, що облік електроенергії у колах з несинусоїдальними режимами залежить від результативності похибки обліку електроенергії індуктивними лічильниками. Встановлено, що найбільшою мірою вплив несинусоїдальності на сумарну похибку таких лічильників проявляється на частотах 11-ї і 13-ї гармонік. Запропоновано для покращення обліку електроенергії та економії коштів бюджету міста встановлення у системах вуличного освітлення сучасних електронних коректорів потужності, які суттєво зменшують похибку обліку.

The problem of load symmetry disturbance and appearance of non-sinusoidal regimes in the three-phase mains power-supply systems of the municipal lighting networks with non-linear parameters of the installed lighting devices, which result in the increase of the meters data and raise of bills payment, has been analyzed. It has been found, that voltage asymmetry in the municipal lighting networks results in the appearance of the inadmissible regimes, caused by the fact, that the gas-discharged lamp lighting devices, which are used in the municipal lighting, in the main non-linear loads, consist of out-of-date electromagnetic circuitry and create noises in the networks: they introduce reactive component, which can hardly be balanced and cause the appearance of higher harmonics. Higher harmonic currents, which are the result of this non-linearity, affecting the total network resistance, cause the network voltage disturbance and appearance of the non-sinusoidal regimes. Current harmonics, penetrating into the power system network, cause the detoriation of the high-freguency communication and automatic systems operation, initiate unpredictable response of some relay protections as well as make worse the electric power calculation. Nowadays for calculation of the electric power inductor counters, which have negative frequency error in the higher harmonic frequencies, are more widely used. It was stressed, that the electric energy calculation in the non-sinusoidal regime circuits depends on the electric power calculation error result, carried out by these counters. The limits of the maximal error of the non-sinusoidal voltage amplitude measurement, depending on the level of the higher harmonics, were found. It was determined that the greatest non-sinusoid effect on the induction counters error is that of the 11th and 13th harmonic frequencies, and depending on the fact, if the load is linear or non-linear, inaccurate calculation of the consumed electric power is possible. These characteristics of the induction counters operation, while being used in the lighting networks, result in the appearance of unexpected results, that is: excessive calculation and calculation defect of the electric energy as to the total consuming power of the lighting devices, which is treated as the power losses, but is fixed by the electric energy meters together with the useful power and is paid for the electric supply institution from the municipal budget funds according to the meters data. One of the possible ways of solving this problem is the installation of modern electronic electronic corrector power., in which the circuitry solutions in the linearity of the input volt-ampere characteristic are applied, which will make possible to improve the efficiency of the electric energy calculation and to save funds.