scholarly journals An Analysis of the Systematic Error of a Remote Method for a Wattmeter Adjustment Gain Estimation in Smart Grids

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 37 ◽  
Author(s):  
Robertas Lukočius ◽  
Žilvinas Nakutis ◽  
Vytautas Daunoras ◽  
Ramūnas Deltuva ◽  
Pranas Kuzas ◽  
...  
Keyword(s):  
Systematic Error ◽  
Power Factor ◽  
Smart Grids ◽  
Low Voltage ◽  
Voltage Drop ◽  
Estimation Method ◽  
Data Communication ◽  
Pattern Search ◽  
Error Monitoring ◽  
Worst Case

Smart energy meters supporting bidirectional data communication enable novel remote error monitoring applications. This research targets characterization of the systematic worst-case error of the previously published remote watthour meter’s gain estimation method based on the comparison of synchronous measurements by the reference and meter under test. To achieve the research aim a methodology based on global maximization of the systematic error objective function assuming the typical low voltage electrical distribution network operation parameters ranges as defined by the standard recommendations for network design. To cross verify the reliability of the assessed solutions the suggested error analysis methodology was implemented utilizing two stochastic global extremum search techniques (genetic algorithms, pattern search) and the third one utilizing nonlinear programming solver. It was determined that the wattmeter adjustment gain worst-case error does not exceed 0.5% if the remote wattmeter monitored load power factor is larger than 0.1 and a network is designed according to the recommendation of the acceptable voltage drop less than 5%. For a load exhibiting power factor larger than cos φ = 0.9 the worst-case error was found to be less than 0.1%. It is concluded therefore that considering the systematic worst-case error the previously suggested remote wattmeter adjustment gain estimation method is suitable for remote error monitoring of Class 2 and Class 1 wattmeters.

scholarly journals High Frequency Solid State Transformer Design Considerations for Power Systems Applications

2021 ◽  
Vol 2 (5) ◽  
Author(s):  
Raton Kumar Nondy ◽  
Md. Abul Bashar ◽  
Prema Nondy ◽  
M. Hazrat Ali
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Power Distribution ◽  
High Frequency ◽  
Low Voltage ◽  
Voltage Drop ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Power Converter ◽  
Voltage Sag

The conventional power frequency (50 or 60 Hz) transformers are economical, highly reliable and quite efficient but they suffer with certain drawbacks like sensitive to harmonics, voltage drop under load, no protection from system disruptions and overloads, poor performance under dc offset load unbalances and no scope to improve power factor. These transformers with copper wound wires on iron cores are unable to respond to control signals as power generations become distributed and intermittent. So, the need of electronic based regulated power supply with software based remote intelligence has become essential. Also, to easily connect the new energy sources to the grid and to improve the power quality by harmonic filtering, voltage sag correction and highly dynamic control of the power flow, a new type of transformer based on power electronics, known as SST has been introduced. The SST realizes voltage transformation, galvanic isolation, power quality improvements such as instantaneous voltage regulation, voltage sag compensation and power factor correction. It is a collection of high-powered semiconductor components, high frequency power transformer and control circuitry which is used to provide a high level of flexible control to power distribution networks. The SST is a high frequency switched Power Electronic Devices (PEDs) based transformer with high controllability that enables flexible connectivity between existing medium voltage power distribution network, low voltage AC residential system and envisioned DC residential system. In this paper a systematic constructional detail of a SST with a power rating of 2 kVA, operating frequency of 20 kHz and voltage rating of 600/60 V as a scaled-down prototype used for power converter topologies is presented. The design is simple and it avoids the difficulty of choosing massive amounts of empirical parameters.

scholarly journals OPTIMIZE THE PERFORMANCE OF ELECTRICAL EQUIPMENT IN GAS SEPARATION STATIONS (DEGASSING STATION DS ) AND ELECTRICAL SUBMERSIBLE PUMPS OF OIL EQUIPMENT FOR OIL RUMAILA FIELD

2019 ◽  
Vol 21 (1-2) ◽  
pp. 141-145 ◽  
Author(s):  
Majid Abdulhameed Abdulhy Al-Ali ◽  
V. Yu. Kornilov ◽  
A. G. Gorodnov
Keyword(s):  
Power Factor ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Drop ◽  
Reducing Power ◽  
Electrical Equipment ◽  
Voltage Regulation ◽  
Total Power ◽  
Electrical Submersible Pumps ◽  
Energy Compensation

Annotation: There are various types of electrical equipment used in the extraction of oil at the Rumaila field, with an average voltage of 11 kV and a low voltage of 0.4 kV. The most common elements in this class are transformers and reactors, engines and gas discharge lamps. All of this equipment consumes reactive power and reduces the value of the power factor. (Power factor is the ratio of kW to kVA). The closer the power factor to the maximum possible value of 1, the greater the benefit for the consumer and supplier. In case of low power factor, the current will be increased, and this high current will lead to (large line losses, an increase in the nominal total power of kVA and overhaul dimensions of electrical equipment, deterioration in voltage regulation process and an increase in voltage drop, a decrease in efficiency).Power factor improvement allows the use of smaller transformers, switchgear and cables, etc. as well as reducing power losses and voltage drop in an installation. Improving the power factor of an installation requires a bank of capacitors which acts as a source of reactive energy. These arrangements provide reactive energy compensation. In Rumila, An improvement of the power factor of an installation presents several technical and economic advantages, notably in the reduction of electricity bills, we save (685.854.007 Iraqi Dinar= 550.000 $) for one month . All this work takes 6 to 12 month.

scholarly journals Increasing the Utilization of Existing Infrastructures by Using the Newly Introduced Boundary Voltage Limits

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5106
Author(s):  
Daniel-Leon Schultis ◽  
Albana Ilo
Keyword(s):  
Smart Grids ◽  
Low Voltage ◽  
Flow Analysis ◽  
Load Flow ◽  
Distribution Grid ◽  
Worst Case ◽  
Voltage Level ◽  
Safety Margins ◽  
Voltage Limit ◽  
Electricity Infrastructure

The increasing share of distributed generation aggravates voltage limit compliance at customers’ delivery points. Currently, grid operators validate compliance with the voltage limits specified in Grid Codes by conducting load flow simulations at the medium voltage level, considering the connected low voltage grids as ‘loads’ to reduce the modeling effort. This approach does not support the accurate validation of limit compliance, as the voltage drops at the low voltage level are unknown. Nevertheless, to guarantee acceptable voltages even under worst-case conditions, safety margins are involved that impair the utilization of the electricity infrastructure. This study conducts load flows simulations in a test distribution grid, revealing the variable character of the voltage limits at different system boundaries. The conventional load model is extended by new parameters—the boundary voltage limits—to enable the consideration of variable voltage limits in load flow analysis of LINK-based smart grids. The standardized structure of the LINK-architecture allows for the systematic and accurate validation of voltage limit compliance by reducing the required modeling data to the technically necessary minimum. Use cases are specified that allows smart grids to increase the utilization of the electricity infrastructure by day-ahead scheduling and short-term adaptation of boundary voltage limits.

Reduction of the Low Voltage Substation Constraints by Inserting Photovoltaic Systems in Underserved Areas

2019 ◽  
Vol 12 (2) ◽  
pp. 105-112
Author(s):  
Benbouza Naima ◽  
Benfarhi Louiza ◽  
Azoui Boubekeur
Keyword(s):  
Low Voltage ◽  
Voltage Drop ◽  
Electrical Energy ◽  
Utilization Rate ◽  
Photovoltaic Systems ◽  
Voltage Distribution ◽  
Medium Voltage ◽  
Pv Systems ◽  
Transformer Substation ◽  
Load Pattern

Background: The improvement of the voltage in power lines and the respect of the low voltage distribution transformer substations constraints (Transformer utilization rate and Voltage drop) are possible by several means: reinforcement of conductor sections, installation of new MV / LV substations (Medium Voltage (MV), Low Voltage (LV)), etc. Methods: Connection of mini-photovoltaic systems (PV) to the network, or to consumers in underserved areas, is a well-adopted solution to solve the problem of voltage drop and lighten the substation transformer, and at the same time provide clean electrical energy. PV systems can therefore contribute to this solution since they produce energy at the deficit site. Results: This paper presents the improvement of transformer substation constraints, supplying an end of low voltage electrical line, by inserting photovoltaic systems at underserved subscribers. Conclusion: This study is applied to a typical load pattern, specified to the consumers region.

scholarly journals Heuristic Optimization of Overloading Due to Electric Vehicles in a Low Voltage Grid

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6069
Author(s):  
Sajjad Haider ◽  
Peter Schegner
Keyword(s):  
Electric Vehicles ◽  
Low Voltage ◽  
Optimization Methods ◽  
Monte Carlo Analysis ◽  
Heuristic Optimization ◽  
Optimization Approach ◽  
Worst Case ◽  
Voltage Drops ◽  
The Individual ◽  
Nodal Voltage

It is important to understand the effect of increasing electric vehicles (EV) penetrations on the existing electricity transmission infrastructure and to find ways to mitigate it. While, the easiest solution is to opt for equipment upgrades, the potential for reducing overloading, in terms of voltage drops, and line loading by way of optimization of the locations at which EVs can charge, is significant. To investigate this, a heuristic optimization approach is proposed to optimize EV charging locations within one feeder, while minimizing nodal voltage drops, cable loading and overall cable losses. The optimization approach is compared to typical unoptimized results of a monte-carlo analysis. The results show a reduction in peak line loading in a typical benchmark 0.4 kV by up to 10%. Further results show an increase in voltage available at different nodes by up to 7 V in the worst case and 1.5 V on average. Optimization for a reduction in transmission losses shows insignificant savings for subsequent simulation. These optimization methods may allow for the introduction of spatial pricing across multiple nodes within a low voltage network, to allow for an electricity price for EVs independent of temporal pricing models already in place, to reflect the individual impact of EVs charging at different nodes across the network.

scholarly journals Dynamic Low Voltage Ride through Detection and Mitigation in Brushless Doubly Fed Induction Generators

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4461
Author(s):  
Ahsanullah Memon ◽  
Mohd Wazir Mustafa ◽  
Muhammad Naveed Aman ◽  
Mukhtar Ullah ◽  
Tariq Kamal ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Low Voltage ◽  
Voltage Drop ◽  
Low Voltage Ride Through ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Reactive Current ◽  
Doubly Fed ◽  
Rotor Side Converter

Brushless doubly-fed induction generators have higher reliability, making them an attractive choice for not only offshore applications but also for remote locations. These machines are composed of two back-to-back voltage source converters: the grid side converter and the rotor side converter. The rotor side converter is typically used for reactive current control of the power winding using the control winding current. A low voltage ride through (LVRT) fault is detected using a hysterisis comparison of the power winding voltage. This approach leads to two problems, firstly, the use of only voltage to detect faults results in erroneous or slow response, and secondly, sub-optimal control of voltage drop because of static reference values for reactive current compensation. This paper solves these problems by using an analytical model of the voltage drop caused by a short circuit. Moreover, using a fuzzy logic controller, the proposed technique employs the voltage frequency in addition to the power winding voltage magnitude to detect LVRT conditions. The analytical model helps in reducing the power winding voltage drop while the fuzzy logic controller leads to better and faster detection of faults, leading to an overall faster response of the system. Simulations in Matlab/Simulink show that the proposed technique can reduce the voltage drop by up to 0.12 p.u. and result in significantly lower transients in the power winding voltage as compared to existing techniques.

scholarly journals Time Synchronized Low-voltage Measurements for Smart Grids

2015 ◽  
Vol 100 ◽  
pp. 1389-1395 ◽  
Author(s):  
Ladislav Stastny ◽  
Lesek Franek ◽  
Zdenek Bradac
Keyword(s):  
Smart Grids ◽  
Low Voltage

An integrated low-voltage rated HTS DC power system with multifunctions to suit smart grids

2015 ◽  
Vol 510 ◽  
pp. 48-53 ◽  
Author(s):  
Jian Xun Jin ◽  
Xiao Yuan Chen ◽  
Ronghai Qu ◽  
Hai Yang Fang ◽  
Ying Xin
Keyword(s):  
Power System ◽  
Smart Grids ◽  
Low Voltage ◽  
Dc Power
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