The Selection of Online Power Flow Calculation’s Known Quantities

2014 ◽  
Vol 986-987 ◽  
pp. 1396-1400
Author(s):  
Ling Wang ◽  
Hai Bao ◽  
Yu Long Chen
Keyword(s):  
Power Flow ◽  
Measurement Accuracy ◽  
Reactive Power ◽  
Power Measurement ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Power Regulation ◽  
Calculation Results ◽  
The Difference ◽  
Selection Of

The difference between schedule power flow and online power flow is that the former has no corresponding physical power flow, while the latter is the reappearance of existing physical power flow. Owing to the different premise, the selection of power flow calculation’s known quantities can be different. A schedule power flow schedules physical power flow for power system, so the selection of known quantities has strict requirements, such as active power and reactive power regulation capability. Since the physical power flow exists, the selection of online power flow calculation’s known quantities can be more flexible. For example, we can choose load bus as slack bus or replace PQ bus with PV bus. The example demonstrated that we could locate the stealing electricity buses by choosing load bus as slack bus. Considering that voltage amplitude measurement accuracy is higher than reactive power measurement accuracy, we can replace PQ bus with PV bus and make the power flow calculation results more consistent with the physical power flow. Finally, the examples show that online power flow calculation’s known quantities can be selected flexibly according to the actual situation rather than strictly following the classical power flow calculation requirements.

scholarly journals Using smart meters for checking the topology and power flow calculation of a secondary distribution network

2019 ◽  
Vol 139 ◽  
pp. 01059
Author(s):  
Irina Golub ◽  
Evgeny Boloev ◽  
Yana Kuzkina
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Distribution Network ◽  
Smart Meters ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Three Phase ◽  
Secondary Distribution ◽  
Linear State ◽  
Selection Of

The paper analyzes options of using smart meters for power flow calculation and for assessing the state of a real three-phase four-wire secondary distribution network based on measurements of average values of active and reactive power and of voltages. The work is based on the authors’ research on allocation of measurements to ensure secondary distribution network observability and on selection of the most efficient method for linear and non-linear state estimation. The paper illustrates solution of a problem on identification composition of load nodes in the phases and reveals challenges related to voltage account in the neutral wire and in its grounding.

The Effect of the Accuracy of Reactive Power Measurement on Transmission Node Cost

2013 ◽  
Vol 816-817 ◽  
pp. 598-601
Author(s):  
Hai Bao ◽  
Xiang Yu Zhang ◽  
Gang Liu ◽  
Ling Wang
Keyword(s):  
Cost Analysis ◽  
Power Distribution ◽  
Power Flow ◽  
Reactive Power ◽  
Power Measurement ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Data Measurement ◽  
The Cost ◽  
Do So

Power flow calculation is the fundamental of cost analysis of transmission node. In traditional methods, the rationality of the cost analysis is of more concern than the accuracy of the power flow calculation’s results. This paper starts from the reactive data that being used for power flow calculation, expatiate that the method of present reactive power data measurement is inaccurate and explains why it is inaccurate. What reactive power would do to node cost analysis and why it could do so are analyzed considering cost analysis of transmission node. At last, an example of IEEE 9 is used. And it is proved that the fluctuation of reactive power will affect the power distribution of the whole network, as a result affect the generators’ sale of electricity income to loads greatly.

A New Method for Online Steady-State Power Flow Calculation in Electric Power System

2013 ◽  
Vol 816-817 ◽  
pp. 1090-1093 ◽  
Author(s):  
Hai Bao ◽  
Xin Huang ◽  
Ling Wang ◽  
Gang Liu
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Active Power ◽  
Electric Power System ◽  
New Method ◽  
Power Measurement ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Measuring Accuracy ◽  
The Given

Owing to the given variables are measurable in online power flow calculation, the electrical variables of higher measuring accuracy should be chosen for calculation. Currently the theory of reactive power is deficient and several methods for reactive power measurement are briefly introduced in this paper. The inaccuracy of those methods is pointed out by the relevant references in non-sinusoidal conditions. The measuring accuracy of Active power directly obtained by voltage and current is the same as that of voltage and current. For increasing the accuracy of online power flow calculation, a method substituting voltage magnitude for reactive power is proposed in this paper. The new method eliminates the effects resulted from inaccurate reactive power measurement. The simulation results on software MATPOWER verify the correctness and rationality of the new method.

scholarly journals The Optimization of the Location and Capacity of Reactive Power Generation Units, Using a Hybrid Genetic Algorithm Incorporated by the Bus Impedance Power-Flow Calculation Method

2020 ◽  
Vol 10 (3) ◽  
pp. 1034
Author(s):  
Insu Kim
Keyword(s):  
Genetic Algorithm ◽  
Power Generation ◽  
Calculation Method ◽  
Power Flow ◽  
Distribution Systems ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Hybrid Genetic Algorithm ◽  
Power Flow Calculation ◽  
Flow Calculation

Dynamic and static reactive power resources have become an important means of maintaining the stability and reliability of power system networks. For example, if reactive power is not appropriately compensated for in transmission and distribution systems, the receiving end voltage may fall dramatically, or the load voltage may increase to a level that trips protection devices. However, none of the previous optimal power-flow studies for reactive power generation (RPG) units have optimized the location and capacity of RPG units by the bus impedance matrix power-flow calculation method. Thus, this study proposes a genetic algorithm that optimizes the location and capacity of RPG units, which is implemented by MATLAB. In addition, this study enhances the algorithm by incorporating bus impedance power-flow calculation method into the algorithm. The proposed hybrid algorithm is shown to be valid when applied to well-known IEEE test systems.

Research of Improved On-Line Power Flow Method

2014 ◽  
Vol 986-987 ◽  
pp. 1651-1654
Author(s):  
Hai Bao ◽  
Ling Wang ◽  
Yu Long Chen
Keyword(s):  
Convergence Rate ◽  
Power Flow ◽  
Measurement Accuracy ◽  
Reactive Power ◽  
Active Power ◽  
Flow Method ◽  
Calculation Results ◽  
On Line ◽  
Power Flow Method

Based on measurement accuracy of reactive power lower than the accuracy of active power and voltage magnitude, this paper proposes an improved on-line power flow method. Through simulation, compared with the conventional power flow, this method improves the accuracy of the calculation results and also has obvious advantages on the convergence rate. Finally, the article analyzes the reasons for this situation.

scholarly journals On-line Update Method for the Sensitivity Consistency Model of Interconnected Power Grid Based on Electric Power Big Data

2021 ◽  
Vol 256 ◽  
pp. 01014
Author(s):  
Shuai Lian ◽  
Bintang Li ◽  
Jianbo Wang ◽  
Rui Jiang
Keyword(s):  
Real Time ◽  
Power Flow ◽  
Power Grid ◽  
Power Grids ◽  
Equivalent Model ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Interconnected Power Grids ◽  
Calculation Results ◽  
Grid Based

Real-time fast calculation of the power flow of the interconnected power grid is an important guarantee for the reliable operation of the interconnected power grid. The topology of the interconnected power grid is complex, and the calculation of the power flow of the whole network is large and timeconsuming. The sensitivity equivalent model can effectively simplify the interconnected power grid and shorten the time of the power flow calculation of the whole network. The operating state of the power grid is constantly changing. In order to ensure the accuracy of the power flow calculation results, it is necessary to update the uniform sensitivity equivalent model in real time. Due to factors such as the vertical management system between the interconnected power grids and the principle of commercial confidentiality, it is difficult to share information between interconnected power grids in real time, and the sensitivity equivalent model cannot be updated in real time, resulting in too much error in the calculation results and no reference value. To solve this problem, this paper proposes an online update method for the sensitivity equivalent model of the interconnected power grid based on power big data to solve the problem of excessive power flow calculation errors caused by the untimely update of the equivalent model parameters, and to ensure the operational reliability of the interconnected power grid.

The Study of Wind Farm’s Equivalence Method and Verification

2012 ◽  
Vol 433-440 ◽  
pp. 4439-4445 ◽  
Author(s):  
Hong Lin ◽  
Qin Chao
Keyword(s):  
Power Loss ◽  
Power Flow ◽  
Wind Farm ◽  
Reactive Power ◽  
Electric Power System ◽  
Wake Effect ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Lower Error ◽  
Collector System

When the scale of wind farm is increased quickly, if not considering the impedance of the collection system within wind farm, the bigger error in power flow calculation may be caused. In this paper a simple equivalence method calculating the collector system equivalence impedance by using the equivalence power loss is proposed and wind farm’s equivalence output power model considering wake effect and wind speed is established. The models are applied in power flow calculation of the natural wind farm connected to Urumqi grid, Xinjiang. The results compared with original system power flow show that this method has lower error. By using the losses in the collector system, the method of computing the equivalence impedance is verified in this paper. The equivalence impedance of collector system is calculated from total active power loss and total reactive power loss and current flow of the collector system. The error analysis showed that the equivalence impedance of collector system has lower error. The test results show that the proposed equivalence method is effective and logical and has a certain practicality. The reference is given for farther studying safety and stability operation of electric power system including wind farm.

Processing Method for the Node of Wind Farm in Power Flow Calculation

2011 ◽  
Vol 383-390 ◽  
pp. 3598-3604
Author(s):  
Jian Ping Zhang ◽  
Zhi Jiang Yan ◽  
Quan Fei Ding
Keyword(s):  
Power Flow ◽  
Wind Farm ◽  
Reactive Power ◽  
Wind Farms ◽  
Test System ◽  
Active Power ◽  
Power Flow Calculation ◽  
Flow Calculation ◽  
Induction Generators ◽  
Terminal Voltage

At present, there are two kinds of common generators in wind farms, which are induction generators (IG) and doubly-fed induction generators (DFIG). Based on the steady state mathematical models of these two kinds of generators, the processing methods of wind farms in power flow calculation are given. The core idea is to express active power of the generator by a function of wind speed and to express the reactive power by a function of active power, slip and terminal voltage, and then the Jacobian matrix will be corrected according to the relation between terminal voltage and reactive power in the wind farm node. Finally, the IEEE 14-bus test system including wind farm is applied for power flow calculation and analysis. The numerical results show that the mentioned methods are feasible and can satisfy the requirements of the engineering application, which can pave a foundation for further research.

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