The high penetration level of solar photovoltaic (SPV) generation systems imposes a major challenge to the secure operation of power systems. SPV generation systems are connected to the power grid via power converters. During a fault on the grid side; overvoltage can occur at the direct current link (DCL) due to the power imbalance between the SPV and the grid sides. Subsequently; the SPV inverter is disconnected; which reduces the grid reliability. DC-link voltage control is an important task during low voltage ride-through (LVRT) for SPV generation systems. By properly controlling the power converters; we can enhance the LVRT capability of a grid-connected SPV system according to the grid code (GC) requirements. This study proposes a novel DCL voltage control scheme for a DC–DC converter to enhance the LVRT capability of the two-stage grid-connected SPV system. The control scheme includes a “control without maximum power point tracking (MPPT)” controller; which is activated when the DCL voltage exceeds its nominal value; otherwise, the MPPT control is activated. Compared to the existing LVRT schemes the proposed method is economical as it is achieved by connecting the proposed controller to the existing MPPT controller without additional hardware or changes in the software. In this approach, although the SPV system will not operate at the maximum power point and the inverter will not face any over current challenge it can still provide reactive power support in response to a grid fault. A comprehensive simulation was carried out to verify the effectiveness of the proposed control scheme for enhancing the LVRT capability and stability margin of an interconnected SPV generation system under symmetrical and asymmetrical grid faults.

This paper proposes a simple numerical method to determine the optimal location of a distributed generation (DG) within the distribution network. The main objective of this work is to find the optimal number, the type, the size and the bus location of DG that would enhance the voltage levels and reduce the power losses of the distribution network. Initially, load flow, using Newton Raphson Method, was carried out without DG to identify the weak busses on the distribution network, then, the load flow simulation was carried out with the DG units being connected on the identified weak busses to evaluated the impact of the DG units on the voltage profile and power losses. The test case IEEE 30 bus system is modeled using standard load flow software. Simulation results with the DG units show improvement in terms of voltage profile enhancement and power losses reduction. Test results indicate that the load flow studies yield positive impact on the 30-bus distribution systems. The maximum power losses reduction was as high as 15.30% and the bus voltage improvement reached 8.72 % for optimally placed single DG and 13.89% for 4 DG units.

The induction of Electromagnetic Fields that are generated through the interaction of high-voltage transmission lines with neighboring buried metallic pipelines produce uncontrolled hazardous potential voltages, which can infringe safety limits. The paper presents the findings of the electromagnetic interference effects on water buried pipelines constructed within the vicinity of an Extra High-Voltage 380 kV transmission overhead line (OHL) in Riyadh-Salboukh route within the Saudi national grid power network. The presented case study showed that some segments of the buried pipelines under this line have not experienced voltages that exceeded the standard limits for the steady-state condition. However, in the event of L-G fault currents (short circuits), the pipelines experienced a voltage level that is above the local electric utility safety limits. Therefore, the work produced implemented the mitigation method of gradient control wires to reduce the potential voltages experienced by the pipelines to enforce the safety limit. The variation of wire resistance has been proven to be a feasible solution to reduce the excessive induced voltages. The comparison has shown that a 0.1 Ω is sufficient to maintain the safe limit for at least this line. These findings may vary depending on the OHL design and site topology.

With the growing concerns about global warming and greenhouse gas emission and carbon footprint drop, all the countries have been moving towards use of renewable energy to meet the future electricity demand. Currently, worldwide solar PV interconnection with power system is increasing. It leads to the many technical problems in the conventional power system network. Large scale PV system connected with power system, to maintain the power supply-demand balance of the system, some the existing fossil fuels power unit needs to be reduced comparatively for maintain the power supply-demand balance of the system. Since the PV system have zero inertia. This leads to the lower system inertia and the higher generator reactance, and hence, the power system transient stability may negatively be affected. This paper investigates the transient stability of the systems with different levels of PV penetration. A two-machine test case system developed using classical model for a synchronous generator, a PV system model and a constant impedance model for load is considered. The potential impact of significant PV penetration on the transient stability is assessed by a numerical simulation using MATLAB-SIMULINK. The critical clearing time (CCT) is calculated by using numerical simulation. The simulation results exhibit both harmful and favorable impacts of increased PV penetration on transient stability performance.

Due to global warming, governments around the world are focusing on renewable energy as the main source of energy. Gulf countries in particular, are focusing on solar energy due to its abundance and the gulf geolocation that allows the installation of ambitious solar photovoltaic (PV) energy systems and replace conventional power plants. In order to maximize energy extraction from the sun, solar power operators need to constantly monitor key solar PV parameters such as panel temperature, solar irradiation, voltage and current in order to detect abnormalities in the PV system operation and take the necessary actions to keep the PV system performance at its maximum. However, monitoring such parameters on-site is exhausting and expensive. Moreover, remote monitoring for solar PV systems is a more attractive solution once the data collection, processing and transmission become faster and less expensive. This paper describes the design of a low-cost remote monitoring system intended for off-grid solar PV systems. The designed remote monitoring system uses a combination of an Arduino Uno Wi-Fi demilitarized zone (DMZ) communication system with router-configured network sensors calibrated to fulfill the IEC-61,724 standards and it provides meteorological and electrical measurements with an error of 2% or less. There are four primary features of the proposed monitoring system. First, it combines the Arduino Uno Wi-Fi with a DMZ configuration in the router. Second, it complies with the minimum current, voltage, power, and PV-module temperature values set by the IEC-61,724 in such a way that the average error does not exceed the 4% threshold. Third, it provides an accuracy level of 98% for the meteorological and electrical parameters. This level of accuracy exceeds that of commercial data logging equipment. Finally, its total cost is less than $100, which is less than that of available commercial solar PV monitoring systems. Additional features include the ability to select the number of processed measurements per hour and innovative processing, display, and access schemes. These features enable the accessibility of the data from mobile phones and computers within the campus for teaching and experimentation purposes.