Tạp chí Khoa học và Công nghệ Năng lượng

PROPOSED 2x2 MIMO TRANSCEIVER SYSTEM USING DOWNLINK STLC AND UPLINK STBC FOR WIRELESS SENSOR NETWORK

2024-04-19T04:22:41+07:00

The Space-Time Line Coding STLC allows the transmitter to send symbols with maximum spatial diversity without needing Channel State Information CSI at the receiver for wireless sensor networks. This coding is similar to Space-Time Block Coding STBC, allowing the receiver to achieve maximum spatial diversity without needing CSI at the transmitter. There have been studies on transceiver architectures for data transmission, such as the Fusion Centre (FC) and sensors in wireless sensor networks WSN. The downlink from the FC to the sensor uses STLC, and the uplink uses STBC. Currently, CSI is only necessary for the FC rather than the sensors. Typically, this architecture uses a model of two antennas for the FC and one antenna for the sensor. This paper applies the 2x2 MIMO model to the FC and the sensor. This improved model will reduce the bit error rate while increasing the channel capacity.

A NOVEL WIDEBAND CIRCULARLY POLARIZED ARRAY ANTENNA FOR WIRELESS MULTI-STANDARDS

2024-04-19T04:31:03+07:00

The paper proposes a novel low-profile wideband circularly polarized array antenna for wireless multi-standards. The circularly polarized array antenna consists of four printed dipole elements, and its feeding network is based on the sequential rotation technique. This proposed antenna operates at the center frequency of 5.8 GHz with a wide bandwidth of 2 GHz (34.4%); a wide axial-ratio 3 dB bandwidth of 1.5 GHz (25.8%); and a high maximum gain of 8.1 dBi. The antenna with a dimension of 50×50 mm² is simulated using CST software. The proposed antenna is suitable for wireless multi-standards such as IEEE 802.11 ac WiFi, WLAN, WiMAX, and the industrial scientific medical (ISM) frequency band.

INVESTIGATION OF POWER SYTEM STABILIZER PERFORMANCE IN FREQUENCY STABILITY OF POWER SYSTEM INTEGRATED WITH WIND POWER

2024-04-19T11:55:39+07:00

The energy transition is implementing in various different industries at a global scale. In particular, the shift from traditional fossil fuel-based power generation technology to renewable energy sources-based ones plays a pivotal role in this process. In many countries including Vietnam, the level of penetration of wind power sources is increasing, on the one hand, contributing to meet the demand of the load, on the other hand and modifying the related technical issues in power systems. The fluctuation of output power of wind power sources following the variation of the wind speed is great challenging to the guarantee of power system stability. This paper introduces research results on the effectiveness of power system stabilizers (PSSs) in improving small signal stability. First, the 9-node IEEE power system is modified with the participation of a wind power source. The operation of PSS that is equipped at a traditional power plant was then investigated in the conditions that there are fluctuations in load and the output of wind power system. The obtained results show different efficiency of PSS types in power system stabilization.

A SOLUTION FOR OPERATION OF MEDIUM VOLTAGE DISTRIBUTION NETWORKS WITH INTEGRATION OF DISTRIBUTED SOLAR PHOTOVOLTAICS

2024-04-19T12:03:07+07:00

The rapid development of small and medium-sized renewable energy sources such as solar power, wind turbine (collectively referred to as distributed power sources) connected to the power distribution grid has led to many impacts on the management and operation of the grid. One of the problems is that the power generated from these sources flows back towards intermediate stations (110 kV), leading to the risk of transformer overload and increased losses on the grid. The paper focuses on the reverse power flow phenomenon, calculation and analysis in different scenarios of distributed solar photovoltaics. The proposed grid restructuring solution shows feasibility in practice, loss reduction and voltage quality improvement to the grid. The results of the paper obtained from a specific medium-voltage grid will be a practical reference for distribution grid management and operation utilities.

DESIGN SLIDING CONTROLLER FOR GRID-CONNECTED INVERTERS USING LCL FILTER

2024-04-19T12:10:30+07:00

This paper presents and proposes some solutions to improve the control quality of grid-connected inverters. The direct power control method uses an external voltage loop design to ensure the stability of the voltage bus as well as obtain the reference value of the internal current loop. Design of internal current loop slip controller to ensure grid current and effective anti-interference. The entire control system is tested through simulation with Matlab/Simulink software.

BUILDING SYSTEM DATA SYNCHRONIZATION MODULE FOR FAULT MONITORING AND EARLY WARNING ON 110 kV POWER LINE

2024-04-19T12:13:23+07:00

During the operation of the power transmission system, the faults on the line still often occur relatively complicated due to many different reasons. To be able to easily perform operational monitoring and early warning of problems on lines in different terrains, information technology, digital signals, artificial intelligence (AI) technology, using unmanned aircraft have been applied and increasingly popular in the world during recent times. Because real-time system monitoring databases are obtained heterogeneously from many different forms, leaving a single and queryable schema that provides users with a unified view of them is not easy. So, the process of synchronizing data on the line is extremely necessary to accurately forecast the type of fault, the location of the fault, and from there to come up with a timely treatment plan. In this study, the research team designed, programmed, and built a data synchronization module for the system from different data sources of the 110 kV line to serve the monitoring and early fault warning on 110 kV power transmission line.

STUDY ON IMPROVEMENT SOLUTION OF THE EFFICIENCY OF SOLAR POWER SUPPLY AT AN BINH ISLAND, QUANG NGAI PROVINCE

2024-04-19T12:16:19+07:00

Applying renewable energy to islands is one of the important solutions in supporting local economic development in most countries of the world. However, the use of wind and solar energy sources for Vietnam's island areas is still facing some challenges such as weather effects, so it is necessary to evaluate the effectiveness of integrating a power storage system of lithium batteries. Therefore, the paper studies the possibility of integratingsolar energy and lithium battery systems into the power grid of An Binh island, Quang Ngai province. The research results show that choosing the appropriate structure of the hybrid power system can contribute to increase the power supply ratio of 20.5% from solar power sources on the island.

STUDYING THE EFFECTS OF LIGHTNING STRIKES TO 500 kV TRANSMISSION LINE AND STATION USING EMTP SOFTWARE

2024-04-19T12:19:26+07:00

According to EVNNPT's reports in recent years, lightning incidents account for about 60-80% of the total incidents occurring on overhead lines. The consequence of the incident caused by lightning is to stop providing electricity to important load households, significantly affecting the production and business of enterprises.

The article focuses on simulating and reviewing the parameters of current, voltage and power generated at some important locations on the feeder line and in the 500 kV substation when lightning strikes the protective wire, lightning on the station's outgoing power pole. Simulation results show the important role of ensuring good grounding at the base of the feeder columns in ensuring the safety of equipment in the station. Based on the results of the current and energy transmitted through the earthing and lightning arrester valves, recommendations on the design and installation of the earthing and lightning arrester valve parameters have been given.

DETERMINATION OF BATTERY ENERGY STORAGE SYSTEM SIZING FOR HYBRID POWER SYSTEM IN PHU QUY ISLAND

2024-04-19T12:23:03+07:00

Currently, Phu Quy Island is being supplied by three power sources: a diesel plant, a wind power plant, and a solar power plant with capacities of 10 MW, 6 MW, and 0.8 MW respectively. The load is expected to achieve a capacity of 8.4 MW in 2025, and 14.9 MW in 2030. With the high increase in load demand, and far from the mainland, the Phu Quy power systems is difficult to get electrical energy from the national power grid. Renewable energy is being extended to meet the high load demand on the Phu Quy island. However, the issues of renewable energy often depend on weather conditions such as solar radiation and the wind’s speed, therefore the diesel power plant is still the main energy supply that causes an increase in the power system operating cost. In order to meet the demand as well as the need for renewable energy using to be optimized in the future, the paper is devoted to determination of the Battery Energy Storage System (BESS) sizing to support Phu Quy hybrid in storage of renewable energy and decrease the operation cost for Phu Quy power system. The installation of renewable energy sources such as wind and solar is difficult to manage, between generation and consumption often has excess and shortage over time. The proposed BESS solution can store energy when there is excess from source and release it to the lines when load demand increases. It’s suitable with the current status of power system on Phu Quy Island, as well as the development trend in the future, especially the COP26 and Power Development Plan VII.

PATTERN RECOGNITION OF FACE IMAGES USING BIDIRECTIONAL ASSOCITIVE MEMORY

2024-04-19T12:26:45+07:00

The focus of the article is the exploration and application of Bidirectional Associative Memory (BAM), a form of recurrent neural network, for the purpose of recognizing human facial images. The article presents a novel algorithmic framework rooted in Hebb's rule, tailored specifically for the recognition of human faces. This pattern recognition system is characterized by its compact size and efficiency. The output signal undergoes testing in conjunction with electronic devices and notification speakers, serving as a reliable indicator for correct and incorrect pattern recognitions. It is adaptable for ON/OFF control, making it well-suited for various applications, particularly in the realm of small and medium-sized systems such as smart homes and their equivalents.

RECONFIGURING THE DISTRIBUTION POWER GRID WITH THE OBJECTIVE FUNCTION OF REDUCING POWER LOSS CONSIDERING OPEN/CLOSE COSTS

2024-04-19T12:29:36+07:00

The reconfiguration of the electrical distribution network is a problem aimed at finding the optimal operating method with various objective functions. In this study, the paper proposes a method using suitable algorithms to find electrical grid configurations that change with the profitability of the solution when the electrical energy loss is minimally greater than the operating cost of opening/closing the electrical switches on the switching devices. The proposed method was tested on the IEEE-33 node sample distribution network and implemented on various test cases. The combination of the loadflow tool of PSS/ADEPT software and Matlab code of the algorithm with the objective function of minimal cost proved to be effective and reliable. The proposed method has shown its effectiveness in a day to bring benefits to the electrical grid management company and the power industry.

COLLECTION AND MANAGEMENT SYSTEM OF MEASUREMENT PARAMETERS FROM RADIO POWER MEASUREMENT DEVICES

2024-04-19T12:32:44+07:00

This article proposes a system for collecting and managing measurement power data for radio transmission stations. The system includes conversion modules connected to the meters and a computer software system built to collect, manage, and store parameters sent from the meters. Measurement data is labeled according to device conditions to support error identification and identification based on machine learning models. The system operates stably in laboratory testing with a measurement source consisting of 05 radio transmitters, using radio frequency power meters with conversion modules connected to Wi-Fi to transfer data to the server. The measurement and collection system can be applied to continuously monitor the status of transmitters in real time, supporting repair and maintenance for base stations in mobile communications.