Improved control of energy consumption by a photovoltaic system equipped with a storage device to meet the needs of a local facility

Abstract

+This paper has considered improving the management of energy consumption by a photovoltaic system with a storage device for a local object connected to the network. The aim of the study is to reduce expenditures when paying for electricity consumed from the network, when loading an object, independent of the time of year, and to eliminate energy generation to the grid. An energy generation control algorithm has been improved whereby the state of battery charge during the day is based on a forecast. That could reduce electricity consumption at night with better utilization of rechargeable battery and photovoltaic battery power during the day. It is proposed to use autonomous operation by disconnecting from the network during peak tariff hours and during the day with enough energy generation by a photovoltaic battery. This would ensure the normal functioning of an object in the event of a possible deterioration in the quality of voltage in the network while reducing the loss of energy in the inverter. Predictive control of the expected battery charge at the next checkpoint (at 0.5 hours or less between control points) has been proposed. A control system structure has been developed whereby a rechargeable battery current is set depending on an operational mode, the tariff zone, and the projected generation by a photovoltaic battery while reducing the modulation frequency under an autonomous mode. In this case, the modes are switched and the structure is changed taking into consideration the state of battery charge. Simulation in the daily cycle has shown the possibility of reducing the cost of electricity consumed from the network by 1.7‒8 times at two or three tariff rates. Simulation of electromagnetic processes in the system confirms acceptable regulation indicators when switching the structure, as well as a decrease in the energy loss in an inverter under an autonomous mode by up to 40 %

Use of Hybrid Photovoltaic Systems with a Storage Battery for the Remote Objects of Railway Transport Infrastructure

“…In Table 1 When solving the issue of increasing the power of the LO, the general approach changes somewhat; the DG becomes an auxiliary source of energy of limited power. As originally proposed, the use of a load schedule was considered in accordance with the standard distribution of peak loads [19,26] for objects of the utility sector and the nondomestic sector with a single-shift mode of operation. The following distribution of load intervals was accepted: night tariff zone in the period May-August (t 7 = 24.00, t 1 = 7.00), day tariff (t 1 = 7.00, t 2 = 8.00), (t 3 = 11.00, t 5 = 20.00), (t 6 = 23.00, t 7 = 24.00), peak load zones (t 2 = 8.00, t 3 = 11.00), and (t 5 = 20.00, t 6 = 23.00); in the period autumn-winter-spring (t 1 = 7.00, t 2 = 8.00, t 3 = 10.00, t 5 = 17.00 and 18.00, t 6 = 17.00 and 18.00, t 7 = 24.00).…”

“…PV generation changes significantly during the day and year. Therefore, the increase in the efficiency of PVS energy management is associated with the use of the forecast of PV generation [15][16][17][18][19]. The issues with obtaining an accurate forecast were considered in a number of studies, particularly [15,16].…”

“…Recently, web resources have been made available that provide a forecast with a discreteness of 0.5 h or less, including an individual one at the location [20,21]. For the application without generation to the grid, the main purpose of the forecast is load planning for the next day and the possibility of adjustment when it changes [19].…”

“…Certain opportunities to reduce the cost of paying for electricity consumed by LO from DG are provided by taking into account the tariffication of payment [19,[22][23][24][25]. Features of the implementation of PVS in the application of static and dynamic tariffs were considered in [22].…”

“…When using PV for the needs of LO (without generating electricity to the grid), it is achievable to reduce the cost of electricity consumption from DG by up to five times at one tariff rate (up to seven times at wo rates) in the summer [19,26]. In winter, the reduction is insignificant-around 1.2 times.…”