Setting Up a Remote Accessing of a PV Plant and Its Analysis

The growing interest and increasing installation capacity of photovoltaic (PV) power plants have increased awareness of the necessity and importance of better management of the PV power plant system in order to obtain the optimal energy yield from the PV power plant. To meet the above objectives, sufficient supervision and monitoring of the health and performance of the PV system is needed. It is observed that the yields and thus the performance ratio of the plants strongly depend on the energy demand as well as the state of charge of the battery.

This is due to the method used to control the flow of energy in the local network. Their kind guidance and advice helped me complete the project within the time allotted by the university. Dr Syed Ihtsham Ul-Haq Gilani always guided me patiently to complete my project and dissertation.

He always encourages and motivates me to further expand my knowledge and step outside my comfort zone. In addition, I would like to thank the Mechanical Engineering Department of Universiti Teknologi PETRONAS for their kind efforts in approving this project.

INTRODUCTION

BACKGROUND OF STUDY
PROBLEM STATEMENT
OBJECTIVES
SCOPE OF STUDY

For small and medium-sized stand-alone PV power plants set up in rural areas, they are normally operated without supervision. Moreover, in some cases, the performance of the PV power plants can slowly deteriorate after some time without exceeding any defined threshold and without issuing any warning of this situation. Due to the reason above, stand-alone PV power plants installed in remote rural areas have normally failed.

Parameters such as ambient temperature, wind speed and energy yield of the PV power plant must be closely monitored to evaluate the efficiency of its system. This project was carried out with the aim of setting up a remote monitoring system for monitoring the PV power plant in UTP. The energy yield of the PV power plant and environmental parameter such as wind speed, ambient temperature and insulation at the site will be monitored through Sunny Portal.

In addition, this project will also study the factors that affect the performance ratio of the PV power plant. Factors such as module temperature, which can be derived taking into account environmental parameters; energy flow control mode of the system, and insolation are the most important main factors affecting the performance of the PV power plant.

LITERATURE REVIEW

INTRODUCTION
PV POWER GENERATION SYSTEM
PERFORMANCE OF PHOTOVOLTAIC PLANT
UTP POWER PLANT SYSTEM CONFIGURATION

Establishing a PV remote monitoring system allows operators to monitor in real-time to perform system performance data analysis to highlight potential faults in the power design, allowing appropriate countermeasures to be applied without being on site. Current is created when a load is connected to both sides of the PV cells. This device is used to manage and prevent overcharging and overdischarging of the battery.

There are several parameters including site location, climate, and many loss mechanisms that affect plant performance. Wiring losses and connection mismatch: The overall energy efficiency of a PV array is generally lower than the actual energy efficiency of individual modules. Sunny Remote Control: Sunny Remote Control offers convenient start-up and control without having to be in front of the inverter.

The rotary switch of the Sunny remote control allows the user to operate it intuitively. The current state of the system is displayed only on four-line displays and is transparently arranged. The charge and discharge status of the batteries is controlled and monitored by bidirectional inverters (SMA Sunny Island 8.0H).

The performance ratio of the PV power plant strongly depends on the energy demand on the state of charge (SOC) of the battery bank.

TABLE 1: Electrical Data of the PV Modules Provided by Canadian Solar Inc (2012) [22], Measured Under “Standard Test Conditions (STC) of Irradiance of 1000 W/m 2 , Spectrum AM 1.5 and Cell Temperature 25 °C”

METHODOLOGY

RESEARCH METHODOLOGY

KEY MILESTONE and GRANT CHART

PROJECT METHODOLOGY

The system performance of the UTP PV power plant is evaluated based on the power generated by PV arrays, inverters and the SOC of battery bank of the PV plant. These indicators in units of kWh/kWp/d are calculated by relating the energies used to the nominal power of the PV array. The PV cell operating temperature, TC of the PV panels is not measured using any sensor connected to the PV panels, as the data logger is located outside the range of effective transmission and accuracy of the measurement would be affected .

It is the annual or daily energy production from the system divided by the peak power as the equation given below [25]. Final yield (Yf) is referred to as the usable amount of energy that originates from the entire solar system. Energy losses show the amount of time the array would need to operate at its rated power, P0 to produce power for the losses [28].

The losses mainly include the two parts: system loss (Ls) and array capture loss (Lc). With the expected effect of electricity production by considering the amount of insulation received by the system compared to the actual current generated by the system. It takes into account the total effect of losses on the rated output due to inverter inefficiencies, wiring faults and others.

RESULT AND DISCUSSION

SUNNY PORTAL MONITORING SYSTEM
PV ARRAY PERFORMANCE ANALYSIS
EFFECT OF TEMPERATURE ON PERFORMANCE RATIO
EFFECT OF POWER MANAGEMENT MODE ON PERFORMANCE RATIO
THE ACCURACY OF INTEGRATED SOLAR RADIATION SENSOR
OVERALL SYSTEM PERFORMANCE

Figures 8, 9 and 10 show the active power output of the SMA Sunny Boy PV inverters and the global irradiance for a cloudy day, denoted as Day 1, a medium-cloudy day recorded as Day 2 and sunny day as Day 3. As discussed in [28], despite the high levels of insolation, the observed drop in the active power generation is due to the way the battery inverter managed the frequency of the power generation system. As we will see in the next section, the PV inverters are instructed by changes in the grid frequency to reduce their output power when the state of charge (SOC) of the battery is high and the demand of the households during the day is low.

As we can see in figures 11, 12 and 13, when the temperature is high, the performance ratio of the power plant drops drastically. Sunny Island two-way inverters are responsible for power management of the PV plant system. Bidirectional inverters regulate the system power flow using droop mode control [33, 34].

The figure shows the SOCs of the battery bank (Figure 14.a), alternating current generated by one of the PV inverters (Figure 14.b) and the frequency (Figure 14.c) for day 3. As can be seen in Figure 14, battery SOC low, as the batteries discharge the previous night, the bi-directional inverters lowered the system grid frequency to 49 Hz to trigger the system to generate AC power when solar power is available. While the solar energy is available and the batteries are charging, the bi-directional inverters begin to raise the system frequency.

When the SOC of the batteries has reached about 91%, the bi-directional inverters raise the system frequency to 51 Hz to limit the power flow. To validate the accuracy of the insolation level detected by the aSi cell, a comparison of the insolation reading is made using two more pyrometers, where Pyranometer 1 measures direct solar radiation and Pyranometer 2 measures global solar radiation for day 1, day 2 and day 3 as it can be seen Figure 15, 16 and 17. From Table 6 we can observe that the performance ratio of the PV plant is low.

Since the power losses are the lowest on day 3, most of the power generated by the PV system is used to charge the battery bank and is consumed by the load. The low values of the achieved PR for the days are mainly due to the decrease in the current supplied to the system as shown in Figure 14 as a result of the way. The decline starts when the SOC of the battery has almost reached its maximum value as shown in Figure 14.b and Figure 14.c.

In this case, the bi-directional inverters raise the system frequency as shown in Figure 14.c, and the PV inverter will start to reduce its AC output as a consequence. However, as discussed in [3, 32], the operating temperature of the cell can also be one of the many factors affecting the performance of the power plant.

FIGURE 4: Insolation VS Ambient Temperature on a Specific Day

CONCLUSIONS & RECOMMENDATION

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