A different vision for uninterruptible load using hybrid solar-grid energy

Received Oct 15, 2018 Revised Nov 11, 2018 Accepted Dec 3, 2018 Attempting to reduce the existing electricity consumption bill, as well as the stability and non-outage grid recharge with the lowest possible cost and suitable quality, is one of the most important goals for those interested in energy around the world. This paper study the circumstances surrounding the Egyptian society to find the best solutions to a achieved this goal, and it was found that solar energy is one of the best alternatives available for energy. Firstly, will be study the electricity consumption bill, slice prices and a program were made to calculate the consumption invoice moreover another program for quick estimation to the proposed solar system. The proposed system provides a smart integration between the solar system and grid, where the supply sustainability and the optimal cost are considered. This configuration allows the two sources separately or simultaneously supply the loads depending on photovoltaic extracted energy. Operational analysis of the proposed system will be discussed in this paper. The proposed system consists of solar cells, charge controller, batteries and inverter plugged to automatic transfer switches (ATS) using Programmable Logic Control (PLC). The system grantee a safe and reliable load feeding independently on the grid status. The system durability is the most depicted feature through the modelling and experimentally results. A typical case studies for about four years of non-outages photovoltaic-grid hybrid supply (the implemented system) will be presented and discussed


INTRODUCTION
Energy challenge has become the most effective one in this century and environmentally friendly solutions in accompanied with a stable grid are becoming prominent. This paper proposes a configuration for a hybrid photovoltaic non-outages grid energy system. Looking for a natural environment without pollutants and sustainable energy solutions to preserve our own for the future generations [1]. Other than hydro power, wind and photovoltaic energy holds the most potential to meet our energy demands alone, wind energy is capable of supplying large amounts of power but its presence is highly unpredictable as it can be here one moment and gone in another, moreover it high cost. Solar energy is present throughout the day but the solar irradiation levels vary due to the sun intensity and unpredictable shadows cast by clouds, birds, trees, etc. [2], [3]. Now the cost of solar power is lower compared to the previous time.The world map for solar radiation Morever, rate and availability in Egypt and the world urged us for use [4], [5]. the price of producing solar energy is becoming lower than before due to the frequent uses for it as shown in Figure 1. Allot of people use this particular clean energy after the sharply increasing in the accounting slice of energy. The common inherent drawback of wind and photovoltaic systems are their intermittent natures that make them unreliable, so it is important to be controlled as well as integrated with other more sources as  [7], [8]. Two experiments with different specification was implemented, the first experiment using 520-Watt polycrystalline photocells and 20A/24DCV PWM charge controller produced 2600 W/Day, the second experimental using 520-Watt mono-crystalline photocells and 20A/24DCV MPPT charge controller produced 3120 Watt/day, more different kinds of loads as lights, motors, compressors, etc. to obtain accurate results. The second experience was the best it efficient than the first experiment by more than 17% of the first experiment.

THE MODEL OF THE PROPOSED SOLAR ENERGY CONVERSION SYSTEM
The model of the proposed non outages hybrid gridphotovoltaic solar energy system consists of the PV solar panels, charge controller, batteries bank, PLC controlled ATS panel and inverter as shown in Figure 2. The system behaves as a load demand optimizer, where the load can fully be supplied by the solar energy in case of the public grid outages [10], [11].

PROPOSED LOAD MAPPING AND MANAGEMENT FOR HOME
Indeed, the ATS has fixed operation profile, and it can be sufficient for several limited needs application. To extend the ATS functionality the PLC look like a suitable solution for dynamic (programmable) ATS system. Programmable ATS controller allows to make an integrated system of domestic energy management depending on the accumulation between the solar and the public utility grid. The system considers that the homeor shops can be divided into subsectionsaccording to needs or emergency loads sections as example for children, grandfather and grandmotheras shown in Figure 3 or shops as general lighting, emergency corridors, surveillance, cameras and counters Section 1 will depend mainly on the solar energy; the other two sections are fed from solar or public utility grid automatically through programmable ATS refer to some conditions [12]. The system is designed to switch the source automatically as shown in Table 1. In case of the outage's public utility grid K1, K3, and K5 contactors are switched OFF then the solar energy contactors K2, K4, and K6 are switched ON.
In case of no-solar energy, all the loads will be automatically connected to the public grid. However, the system is automated, the whole system manual switching is provided. Tabulation the design rules for operating and controlling the three different sections are explored in Table 1. The solar energy system integrated with public grid through programmable ATS achieveeasiness to changing the electrical feeding to localized loads of this work ATS control panel and solar panels as shown in Figure 4.

PERFORMANCE PARAMERTER OF HOME SOSLAR SYSTEM
The rated and the prices of the system components at 2014 are listed in Table 2 The duration of full loaded system has been exprementaly determined by a full load operation and fully OFF Grid. The system can grants a successfully load operation for 12Hrs. However the non-outages supply demandes is the most dominat aim of this work, one can consider a partly non-outages supplies.For axample the non interruptable supply duration of the proposed system can be extreemly extended with a smart load mangement system (LMS). The system output current was 6 Ampare within the full load duration as well as 220 V system output voltage. It can successfully feed the full non outage loads for a lot ofhours. Cost optimization has been considered by transferring part of the loads to the solar energy system to be in a lower accounting slice. Els.
--220 Total 9000 The lower cost of the proposed system infera structure and long life time are some salient features of this system.Through about 6.4 years the system can succeuffly recover his cost. Furthrmore, in case of consumption higher than 1000 KW monthly, the system cost will recoveed through 3.8 years

CATEGORIES FOR ENERGY LOADS CONSUMPTION SYSTEM
There are different categories forenergy consumption of power system such as residence, commercial, industrial and/or agricultural as shown in Figure 5. Each type of this consumption is divided into slices. These slices were worked out to try to help the first tranches to low the suffering of low-income citizens. This is clearly reflected in household and commercial consumption and are those who benefit from different segments of consumption while agricultural and industrial consumption has a single slice [13], [14].

Figure 5. Consumption category slices
According to the Electricity Regulatory Authority and Consumer Protection Regulatory Authority. Common classification of the average energy consumption for home has been listed in Table 3   Table 3. The summarized value of monthly home electrity bill The customer consumption is usually located between seven slices of table 3, these slices are divided into three separate levels; low, normal and high. The low level has couple of slices S 1L and S 2L ,

CUSTOMER CONSUMPTION CALAULATION
Assuming the total home consumption is C T (Kw/Month), the slide number consumption is S s , the slide consumption is C s (Kw), the Kw (Egyptian Pound) price is P s , customer service price for slice is R s (Egyptian Pound), low level consumption is L L , normal level consumption is L N , high level consumption is L H ,T S is the total slice consumption (Egyptian Pound), M S total slice consumption EGP and P T is the total customer consumption (Egyptian Pound) can be obtain as in following (1). Electrity bill value calculation as shown in Figure 6.

Case Study
For example, the home customer consumption CT is 90 (Kw/Month) can be analyzed and cost calculated using (1) & (2) as follows. The total consumption CT 90 Kw/month should be reviewed to Table 3 for determined the level and slice Ss; then found this consumption in low level consumption LLand in the second slice.

BILLS CALCULATOR
The following program is a quick calculation for Bill value as in Figure 4. Just input the total cousumption data in Kw and type of consumption to get the total value of the bill in EGP. Consumption of 700 Kw For example, the invoice value varies according to the type of residential is 539.5 EGP, commercial is 860 EGP, agricultural is 354 EGP or industrial be 785 EGP consumption as shown in Figure 6.

LOCALIZED PERSONAL HOME SOLAR SYSTEM ESTIMATIN.
Quick and simple calculation for the basic energy, consumption of the economical residential can be discussed as follows basic an apartment units (section). An apartment of single room should include kitchen, bathroom, common areas and many balconies. The apartment can be extended to include several rooms as well as more than one bathroom. However, the apartment power consumption can be estimated a cording to the flowchart of Figure 7.
This estimated consumption power the solar system (panels, charge controller, batteries bank and the inverter) are opted based overall cost of the solar system will be also determined using the estimator. When have a building consists of 2 units 170 m 2 each, 2 units 200 m 2 each and one-unit 20m 2 for doorman then the solar system which we need to overcome this building is 15.2 KW and its price be 258,400 EGP.Starting current for motors and compressors is an important concept in this design.

CONCLUSIONS
A cost and non-interruptible optimized hybrid solar-grid system has been proposed, simulated and realized. The system offerred the possibility of working with ON/OFF grid. The maximum permissible extracted energy from solar cells is one of the system features. Actual sustainability has been experimentally accomplished where the battery bank was designed to cover the daily load requirements. The system ATS is configured for an automatic navigation between manual or automated switching. The system has been modeled, implemented and tested using the Matlab Simulink packages. Two years, the electricity bills have been attached and compared with the photovoltic output meters. A cost and non-interruptible optimized hybrid solar-grid system has been proposed, simulated and realized.
Then get the following: a. 35% reduction has been gained according to the official bills. b. The system offered the possibilities of working in parallel with grid. c. The maximum permissible extracted energy from solar cells is one of the design criteria. d. Actual sustainability and satisfactory agreement have been experimentally fulfilled. e. The programmable system ATS has been configured for an automatic navigation between manual or automated switching. f. A clear cost reduction of the supported public grid electricity.