CC BY
1УДК 621.75 Isayeva T.M., Hajiyev R.E.
Isayeva T.M.
Associate professor Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
Hajiyev R.E.
Master student Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
APPLICATION OF PLC CONTROL SYSTEMS IN SOLAR PANELS
Аннотация: Programmable Logic Control (PLC) is an industrial computer specially designed to control the manufacturing process, such as robotics, assembly line, power plant, etc. PLC control program analyzes the input signal to decide the output state according to what has been pre-programmed by the user. This paper discussed the application of PLC as an ATS for on-grid PV system at PLTS Jakabaring which is the biggest PV power plant in Palembang. Data results show the application of PLC as an ATS for PV system, the ATS hold an essential role for the system due to the system independence of solar irradiance.
Ключевые слова: SCADA, PV systems, PLC, Analog inputs, Inverter, Solar Power Plant.
ATS is used to control the transfer of power from the main source (utility power) to the backup source (generator) using a machine controller and relay switches that are placed in one electrical panel [2-4]. ATS systems are excellent domestic application and are cheaper and easier to install than conventional switches [6]. The main thing in Automatic Transfer Switch is to produce power with a low-cost relay. ATS disconnects utility and generator through circuit breakers that provide fast protection and provides a form of electrical interlock. This is a crucial feature when seeking compliance standards. ATS does not have to be able to continuously
feed the power back from the generator to the utility. Therefore it also functions to prevents unnecessary backfeeding [2]. Photovoltaic (PV) is a semiconductor device that can change irradiance from the sun into electricity. If the solar cell receives a beam of light, the output terminals produce DC current, therefore it is sometimes called DC power plants. On-grid PV systems have the advantage of utilizing the power delivered more effectively. However, the technical requirements of the power system network side and PV system side must be synchronized to ensure PV security and utility network reliability. Clarifying technical requirements for grid-interconnection and how to solve the problems arose by the connection is a significant issue for on-grid PV system. This paper discussed the application of PLC as an ATS for on-grid PV system. The data is taken and analyzed from a PV System in Jakabaring Palembang, Indonesia that is intended to power Jakabaring sports city, where the Asian Games 2018 is held. PLTS Jakabaring (Jakabaring Solar Power Plant) is the biggest PV power plant in Palembang. Therefore it is interesting to discuss the application of PLC as an ATS in controlling which electric power source used to power Jakabaring Sports City to ensure there is no power outage during Asian Games 2018.
PLC as an ATS in this study is to switch electric power source from Jakabaring Solar Power Plant to PLN (State Electricity Company). If interference occurs or the generated power is not enough to supply Jakabaring Sports City, the ATS will automatically switch to PLN. ATS is typically multi-pole switches. Thus, an automatic transfer switch used with a three phase, four wire system will always include three poles for switching the three phase conductors of the load between the three phase conductors of the regular power source and the three phase conductors of the emergency power source. The fourth, neutral conductor of the load is often permanently connected to the neutral conductors of the normal and emergency sources. Figure 1 shows the layout design of PLC as an ATS in Jakabaring Solar Power Plant. The PC that is used serves to remotely monitor which must be connected to the internet network and has been synchronized with the PLC using a LAN (Ethernet) cable. Remote monitoring is used as a device that can be controlled
by sending control information and receiving information status from equipment connected to the network. The operator interfaces enable monitoring the process commands such as set point changes. However, the networked modules that connect to the field sensors and actuators are performed by a controller. SCADA connects to remote I/O to collect the data from Inverter and current PV from the combiner box and also included is the alarm of surge detection in the box. It is the interface to 5 Remote I/O equipment system which supports 32 Analog inputs and 32 Digital inputs and performs as a Data logging and control system to collect all data from Inverter, Meter, Temperature Sensor, WIND sensor and pyranometer and the current of Solar combiner box.
Figure 1. Layout design PLC at Jakabaring Solar Power Plant Palembang.
The controller sends all data to the server via GPRS modem and stores all of the data into memory. The client software can connect to the web browser to log in to the system and see the SCADA real-time status, Alarm, Event, Power consumption, Communication efficiency, Inverter status, Electricity production, DC and AC
voltage, and current logging and Trend graph, etc. Weather monitoring is used to monitor the weather around the solar panel. The purpose of using this sensor to observe the daily weather since PV system production depends on the amount of irradiance that is received by the panels. Weather monitoring consists of various components, namely:
Pyranometer is a sensor used to measure solar irradiance on a PV panel surface and solar radiation in flux density W/m2.
Outside Lufft Sensor, is a sensor used to measure temperature, humidity, air pressure, wind speed and direction, solar direction, brightness, and global radiation dusk. This sensor is connected through the RS485 interface serial.
Temperature module consists of a series of temperature sensors.
Figure 2. Layout PLC switch for an on-grid position at Jakabaring Solar Power Plant Palembang.
Conclusion. Jakabaring Solar Power Plant is an on-grid PV system connected to PLN. The application of PLC as an ATS at Jakabaring Solar Power Plant is to automate the switching proses of exporting and importing electrical energy to ensure
no power outage in Jakabaring Sports City during Asian Games 2018. The data is taken before the event, however, the load needed to power are more-less the same. Data results show the application of PLC as an ATS for a PV system, and the ATS hold an important role for the system due to the system independence of solar irradiance. Without the application of ATS, the possibility of power outage due to weather condition that can change dramatically during the day.
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