STRUCTURE-INDUCED BIFURCATION IN LARGE-SCALE ELECTRIC POWER SYSTEMS

2008 ◽  
Vol 18 (05) ◽  
pp. 1415-1424 ◽  
Author(s):  
SHAO-HUA LI ◽  
HSIAO-DONG CHIANG
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Large Scale ◽  
Reactive Power ◽  
Electric Power System ◽  
Small Power ◽  
Operating Limits ◽  
Power Limits ◽  
System Operating

A structure-induced bifurcation of nonsmooth nonlinear systems is studied and illustrated on electric power system models. The consequence of structure-induced bifurcation is an immediate instability induced by generator reactive power limits. It is numerically shown that structure-induced bifurcation can occur at both small power systems and large-scale power systems. Without taking the structure-induced bifurcation into account in defining power system operating limits, the resulting operating limits can be overly optimistic.

scholarly journals A Novel Methodology for Adaptive Coordination of Multiple Controllers in Electrical Grids

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1474
Author(s):  
Ruben Tapia-Olvera ◽  
Francisco Beltran-Carbajal ◽  
Antonio Valderrabano-Gonzalez ◽  
Omar Aguilar-Mejia
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Large Scale ◽  
Short Circuit ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Electric Power System ◽  
Design Stage ◽  
Positive Interaction

This proposal is aimed to overcome the problem that arises when diverse regulation devices and controlling strategies are involved in electric power systems regulation design. When new devices are included in electric power system after the topology and regulation goals were defined, a new design stage is generally needed to obtain the desired outputs. Moreover, if the initial design is based on a linearized model around an equilibrium point, the new conditions might degrade the whole performance of the system. Our proposal demonstrates that the power system performance can be guaranteed with one design stage when an adequate adaptive scheme is updating some critic controllers’ gains. For large-scale power systems, this feature is illustrated with the use of time domain simulations, showing the dynamic behavior of the significant variables. The transient response is enhanced in terms of maximum overshoot and settling time. This is demonstrated using the deviation between the behavior of some important variables with StatCom, but without or with PSS. A B-Spline neural networks algorithm is used to define the best controllers’ gains to efficiently attenuate low frequency oscillations when a short circuit event is presented. This strategy avoids the parameters and power system model dependency; only a dataset of typical variable measurements is required to achieve the expected behavior. The inclusion of PSS and StatCom with positive interaction, enhances the dynamic performance of the system while illustrating the ability of the strategy in adding different controllers in only one design stage.

scholarly journals Assessment of the Impact of Geomagnetic Disturbances on Korean Electric Power Systems

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1920 ◽  
Author(s):  
Byoung-Soo Joo ◽  
Jung-Wook Woo ◽  
Jeong-Hun Lee ◽  
Injoo Jeong ◽  
Jungmin Ha ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Reactive Power ◽  
Electric Power Systems ◽  
Geomagnetic Disturbance ◽  
Electric Power System ◽  
System Stability ◽  
Geomagnetic Disturbances ◽  
The Impact

Geomagnetic disturbances have the potential to impact the operation of electric power systems, and thus the assessment of their impacts is required as the first step for secure power system operations. While the effects of the disturbances have been observed primarily at higher latitudes, geomagnetic problems are also observed at mid and low latitude locations, in particular including neighboring countries to Korea such as China and Japan. This paper deals with the assessment of impact of geomagnetic disturbances on Korean electric power systems. For the assessment, the geoelectric fields induced by the geomagnetic disturbances are calculated using geomagnetic data measured over the past 20 years in order to quantify the strength of geomagnetic events in Korea. Then, the geomagnetic currents on the grid driven by the geoelectric fields are computed. Finally, the increased reactive power absorption in high voltage transformers is analyzed and accordingly the change of system voltage magnitudes is identified to evaluate whether the system maintains the voltage stability. The systematic study concludes that during a strong geomagnetic disturbance, the Korean electric power system satisfies the associated standards in the U.S. and maintains system stability.

scholarly journals A New Transient Frequency Acceptability Margin Based on the Frequency Trajectory

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Ancheng Xue ◽  
Jiehao Cui ◽  
Jiawei Wang ◽  
Joe Chow ◽  
Lei Yue ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Critical Frequency ◽  
Frequency Offset ◽  
Electric Power System ◽  
Stable Operation ◽  
Time Duration ◽  
Small Power ◽  
Multiple Parameters

When the electric power system is disturbed, the transient frequency deviation may be large and harmful to its stable operation, especially in some small power systems. However, there is a lack of transient frequency acceptability margin (TFAM) which could be directly used by dispatchers. In this paper, a new TFAM is proposed based on the transient frequency acceptability index (TFAI). First, based on the frequency trajectory and the philosophy of “different weights to the different frequency offset levels”, a new TFAI is proposed combined with frequency thresholds and time duration limits. The effectiveness of the TFAI is verified, and the critical acceptable disturbance is determined by using the TFAI. Then, a new TFAM is proposed based on the critical acceptability disturbance. The proposed TFAM can quantitatively describe the distance of the operation point from the critical frequency acceptability point, and distinguish the transient frequency acceptability of different disturbances. Finally, with different simulations, the effectiveness and applicability of the proposed TFAM are verified. The TFAM can be used for disturbances with single-parameter and multiple parameters.

Devices for Synchronized Phasor Measurements of Electric Power System Operating Parameters under Different Conditions of Their Operation

2018 ◽  
Vol 6 (6) ◽  
pp. 16-23
Author(s):  
Boris K. MAKSIMOV ◽  
◽  
Tat’yana G. KLIMOVA ◽  
Andrei V. ZHUKOV ◽  
Dmitrii M. DUBININ ◽  
...  
Keyword(s):  
Power System ◽  
Electric Power ◽  
Electric Power System ◽  
Operating Parameters ◽  
Phasor Measurements ◽  
System Operating

A Procedure of Drawing up Integral Indicators for Comprehensively Estimating the Properties of Electric Power System Nodes

Vestnik MEI ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 11-18
Author(s):  
Nailia Sh. Chemborisova ◽  
◽  
Ivan D. Chernenkov ◽  
Keyword(s):  
Power System ◽  
Electric Power ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Reactive Power Compensation ◽  
Electric Power System ◽  
Power Losses ◽  
System Operation ◽  
Active Power Losses ◽  
System Nodes

The problem of selecting the electric power system control nodes is studied. By performing control of these modes, matters concerned with providing reliable power supply of the required quality to consumers can be settled in the most efficient manner. As an example, a fragment of the electric power system mathematical model used in the Finist mode-setting simulator for a power system dispatch control center operator is considered, which represents a highly branched electrical network consisting of eleven 110 kV nodes, three 220 kV nodes connected with the system, and two generator nodes. A new procedure for selecting the control nodes is proposed, which takes into account a combination of different indicators having different measurement units, dimensions and scales is proposed. These indicators characterize the following properties of power system nodes: the reactive power fraction absorbed at a node, the sensitivity of voltage to reactive load variations, the number of connected power lines, and statistical indicators characterizing the change of voltage at the nodes and reactive power flows for different options of installing the reactive power compensation devices. For combined use of these indicators, they were ranked according to the efficiency of installing reactive power compensation devices in the system. For each indicator, a scale of five ranks (intervals) is set, which determine the preferences (qualitative judgments) of the researcher in evaluating the reactive power compensation devices installation efficiency at the system nodes. The highest rank (5) corresponds to the maximum efficiency, and the lowest rank (1) corresponds to the minimum efficiency. To calculate the individual (integral) priority indicator of installing reactive power compensation devices, the ranks of indicators are added together, and their sum is divided by the product of the number of ranks by the number of the used indicators (features). Based on the calculation results, the rating (location) of each node is determined, and the nodes for installing the reactive power compensation devices are selected according to their effect on ensuring the electric power system operation reliability, active power losses in the network, and voltage regulation. Thus, a new procedure is presented for determining the integral indicators for comprehensively estimating the properties of complex electric power system nodes and selecting the controlled nodes using a system of various indicators. These indicators characterize the studied nodes in terms of the efficiency of installing reactive power compensation devices to reduce active power losses in the network, voltage regulation, and ensuring the electric power system operational reliability. The validity of the results obtained in the study is confirmed by their comparison with the indicators of the balance-conductivity method, which has proven itself in solving problems connected with determining the nodes for controlling electric power system operation modes.

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