Bus Participation Research Articles

Urban walkability and tour bus travel

Urban walkability is receiving increasing research attention due to the environmental and health benefits of walking in comparison to driving, yet little is known regarding the walking behaviors of urban visitors who arrive by tour bus. The purpose of this study is to investigate the walking behaviors of diverse tour bus user groups visiting a spatially complex urban destination to better understand urban walkability, barriers to walking, and the derived benefits to walking for tour bus participants. Using an immersive mixed-methods approach, researchers collected eight days of on-bus/off-bus data to document information specific to walking activities, site-to-site transport, tour bus cruising/idling, operational efficiency, mobility, access, and safety. Four target visitor groups included school age, adults, international, and senior citizen veterans. Pedestrian miles traveled ranged from 2.0 to 10.5 miles during tours that lasted between 4.30 and 14.15 h, while primary barriers to walking included itineraries, weather, and safety considerations. Addressing the psychology of walking to evolve from utilitarian to a purposefully integrated leisure activity within tour bus itineraries is the key to decreasing dependency on tour buses for site-to-site transport in urban destinations. Management implications•Spatially complex urban park designs should consider walkability factors such as access, connectivity, path quality, safety, and aesthetics.•Policies that highlight and reward smart mobility should be prioritized to increase utilitarian and leisure walking in urban parks.•Tour mode bundles should purposefully embed walking activities in itineraries to increase physical benefits and participant satisfaction.

O077 The Impact of Breaking up sitting during Simulated Nightshifts on Driving Performance during the Commute Home

Abstract Introduction The commute home from a nightshift is associated with increased accident risk. Driving performance strategies typically occur immediately before or during the commute, such as napping and caffeine. It is unknown whether strategies that target alertness throughout the nightshift could impact the commute home. Breaking up sitting with walking is an effective strategy to improve alertness during dayshifts. This study investigated the impact of breaking up sitting during the nightshift on driving performance post-shift. Method 41 adults (age M±SD: 24.4±4.6 years; 21 females) participated in a 7-day laboratory study, with 5 nightshifts (2200-0630). Participants were randomly allocated to: Breaking up sitting (BUS; n=21) or Sedentary (SED; n=20). Every 30-min during the nightshift BUS participants completed 3-min bouts of light-intensity walking, while SED participants remained sitting. At 2130 (pre-shift) and 0700 (post-shift) participants completed a 20-min simulated drive and the Karolinska Sleepiness Scale. Results Linear mixed models revealed a significant interaction between time (pre- or post-shift) and nightshift on driving performance and sleepiness, such that there was increased lane variability (p=0.03), speed variability (p<0.05), and sleepiness (p<0.05) post-shift compared to pre-shift, with performance worse on the first nightshift. There were no significant 2-way or 3-way interactions between condition (BUS or SED), time, or nightshift. Discussion Breaking up sitting with light-intensity walking did not improve performance for the commute home. However, given that breaking up sitting did not increase risk on the commute home, and it has benefits for cardiovascular health, it is an important strategy to promote to nightshift workers.

O073 The Relationship between Circadian type and Physical Activity on Cognitive Performance during Simulated Nightshifts: A Randomised Controlled Trial.

Abstract Introduction Physical activity might be a nonphotic strategy which could improve cognitive performance for nightshift workers. Innate characteristics like circadian type may also influence individual performance. Thus, this study explores the relationship between circadian type and physical activity on cognition over consecutive nightshifts. Methods Thirty-two healthy adults (age M±SD: 24.3±4.6 years; 19 females) participated in a 7-day laboratory study, with 5 nightshifts (2200-0600). Participants were randomised into the Breaking up sitting (BUS; n=19) or Sedentary (SED; n=13) condition. Overnight, BUS participants completed 3-min bouts of light-intensity walking every 30-min, while SED participants remained seated. At 2200, 0000, 0200, 0400 and 0600, participants completed the 10-min Psychomotor Vigilance Task (mean RRT). Participants completed the 11-item revised Circadian Type Inventory (factor 1: rigid/flexible; factor 2: languid/vigorous), resulting in four-subgroups (rigid; n= 12, flexible; n= 11, and languid; n= 11, vigorous; n= 13). Participants may only be one type from either factor (i.e. rigid and vigorous). Results Linear mixed models showed a significant 3-way interaction between nightshift (1-5), condition (BUS, SED), and circadian type (rigid/flexible) for mean RRT (p=0.03), such that flexible types in the Breaking up sitting condition outperformed Sedentary flexible types and Breaking up sitting rigid types, with performance worse on the first nightshift. There were no significant interactions between nightshift, condition and circadian type (languid/vigorous). Discussion Breaking up sitting improved performance for flexible types over rigid types. These findings have significant implications for nightshift rostering, suggesting that incorporating breaking up sitting may optimise cognitive performance, and therefore work efficiency.

Technique for Reactive Loss Reduction and Loading Margin Enhancement Using the Curves of Losses versus Voltage Magnitude

This paper presents an alternative methodology to obtain the precise amount of shunt reactive power compensation in order to simultaneously reduce the total reactive power losses, improve the voltage profile and increase the loading margin of power systems. The amount of shunt reactive power compensation to be allocated is determined based on the curve of the total reactive power losses versus the voltage magnitude of a chosen bus. The best places for shunt reactive compensation are defined by the load bus participation factors of the critical mode provided by the static modal analysis. Simulation results employing shunt capacitors obtained with the new approach for the IEEE test systems (14, 57 and 300 buses) show that the procedure leads to a reduction in total reactive and active power losses and simultaneously improves the voltage profile and loading margin.

Comparison of Voltage Stability Index Before and After Wind Turbine Penetrated to Sulseltrabar Interconnection Power System Using Modal Analysis Method

Voltage stability problems and renewable energy penetration in power systems are the main issues in the electric power system at this time. This paper aims to examine the condition of voltage stability at the time before and after the entry of wind power plants in the sulseltrabar interconnection system. There are two wind power-generating units that will be studied, namely the PLTB Sidrap with a capacity of 75 MW and the PLTB Jeneponto with a capacity of 72 MW. The simulation using Matlab program. From the simulation results, it can be seen that Sulseltrabar’s voltage stability interconnection system at the time of the entry of PLTB Sidrap and PLTB Jeneponto, has improved stability, this can be seen from the eigenvalue and bus participation factor values. From the minimum eigenvalues it can be seen that the penetration of PLTB Jeneponto is slightly better than PLTB Sidrap in improving voltage stability. The condition that has the greatest influence on improving stability is when the two wind power plant enter to the Sulseltrabar interconnection power system.

Voltage stability assessment of the Southern Sulawesi power system in Indonesia for 2020 by using modal analysis

This paper presents the voltage stability analysis assessment of the Southern Sulawesi power system in Indonesia for the year 2020, considering the load increase every year, the addition of new power plants as well as the large additional load of smelter industries in the Bantaeng Regency. The voltage stability method used in this paper is the modal analysis method. Modal analysis method uses the Jacobian reduction matrix resulting from the Newton-Raphson power flow analysis. Modal analysis produces eigenvalues for each load bus in the system. The bus with the smallest eigenvalue becomes the focus in determining the stability of the system. Then bus participation factor is determined to obtain the most influential bus to improve the stability. The results of this study confirm that by 2020, the Southern Sulawesi power system will be in a stable condition, with the smallest eigenvalue of 5.8 in bus Pare-Pare while bus Barru has the highest bus participation factor.

Bus Participation Factor Analysis for Harmonic Instability in Power Electronics Based Power Systems

Compared with the conventional power systems, large-scale power electronics based power systems present a more complex situation, where harmonic instability may be induced by the mutual interactions between the inner control loops of the converters. This paper presents an approach to locate which power converters and buses are more sensitive and have a significant contribution to the harmonic instability. In the approach, a power electronics based system is introduced as a multi-input multi-output (MIMO) dynamic system by means of a dynamic admittance matrix. Bus participation factors (PFs) are calculated by the oscillatory mode sensitivity analysis versus the elements of the MIMO transfer function matrix. The PF analysis detects which power electronic converters or buses have a higher participation in harmonic instability excitation than others or at which buses such instability problems have a higher impact. In order to confirm the effectiveness of the presented approach, time-domain simulation results are provided for a 400-MW wind farm in PSCAD software environment.

A Steady State Voltage Stability Analysis of Wind Power Centralized System

It is significant to research the voltage stability of the wind power centralized system (WPCS) for the effective development of the large scale clustering wind energy resources. A steady state voltage stability analysis of the WPCS by employing the PV curve and model analysis is proposed to reveal the voltage stability influence from different aspects. The PV curve is utilized to trace and indicate the voltage collapse point of the WPCS when the small disturbance of wind power is increased gradually. Then the steady state voltage instability modes of the WPCS are analyzed by calculating the bus participation factors of the minimum eigenvalue model at the collapse point. The simulation results of an actual WPCS in North China show that the static state voltage instability mode of the WPCS is closely related to the operating features and control strategies of different reactive power sources. In addition, the implementation of the doubly-fed induction generator wind turbine generator voltage control is beneficial to improve the WPCS voltage stability.

Optimal selection of distributed generating units and its placement for voltage stability enhancement and energy loss minimization

Abstract The integration of distributed generation (DG) in distribution network may significantly affect its performance. Transmission networks are no longer accountable solely for voltage security issues in distribution networks with penetration of DGs. The reactive power support from the DG sources greatly varies with the type of DG units and may potentially distress the larger portion of the network from the voltage stability aspects. This paper presents the analysis for the selection of the best type of DG unit among different categories and its optimal location that can enhance the voltage stability of distribution network with simultaneous improvement in voltage profile. Voltage sensitivity index and bus participation factors derived from continuation power flow and Modal Analysis, respectively, are used together for voltage stability assessment and placement of DGs. Changes in mode shapes and participation factors with the placement of DGs are comprehensively analyzed for 33 and 136 nodes radial distribution network.

A Review of Voltage Stability Assessment Techniques with an Improved Voltage Stability Indicator

Abstract A blackout can take place in entire power system or a part of the system due to extreme voltage instability (voltage collapse) that can appear abruptly. Instability prediction and continuous monitoring of the power system performance is, therefore, known exigent. This paper is conducted with a broad overview of the voltage stability indices, which are previously studied in the literature, and have the same foundation during their formulation. Afterward, an improved voltage stability indicator is introduced as a result of the multi-criteria integration and enhancement of the original indices by employing linear algebra methods. It is found that the proposed algorithm can overcome on the probable limitations from calculating point view. Then comparative analysis of the indices is presented in order to reach a unique consensus about the typical techniques of modal analysis (sensitivity, eigenvalue, right eigenvectors, and bus participation factor) as a precise algorithm. Finally, the IEEE 14-bus, and 30-bus test systems are selected to verify the algorithm, and compare the performance of the improved indicator approach with the existing indices.

TLBO based Voltage Stable Environment Friendly Economic Dispatch Considering Real and Reactive Power Constraints

In view of growing concern towards environment, power system engineers are forced to generate quality green energy. Hence the economic dispatch (ED) aims at the power generation to meet the load demand at minimum fuel cost with environmental and voltage constraints along with essential constraints on real and reactive power. The emission control which reduces the negative impact on environment is achieved by including the additional constraints in ED problem. Presently, the power system mostly operates near its stability limits, therefore with increased demand the system faces voltage problem. The bus voltages are brought within limit in the present work by placement of static var compensator (SVC) at weak bus which is identified from bus participation factor. The optimal size of SVC is determined by univariate search method. This paper presents the use of Teaching Learning based Optimization (TLBO) algorithm for voltage stable environment friendly ED problem with real and reactive power constraints. The computational effectiveness of TLBO is established through test results over particle swarm optimization (PSO) and Big Bang-Big Crunch (BB-BC) algorithms for the ED problem.

Voltage Stability Assessment of Large Power Systems and Identification of Weekest Buses

This paper discusses the voltage stability analysis of large power systems using a modal analysis technique. Voltage instability within a power system has a severe consequences including wide spread low voltage profile and system blackout. The development and use of accurate methods to predict incipient voltage instability is crucial in preventing such voltage collapse situations. Voltage collapse may cause the outage in the entire power system. A modal analysis technique computes using steady state system model, a specified no. of smallest Eigen values and the associated Eigen vectors of reduced Jacobian matrix. The Eigen value provides relative measure of proximity to voltage instability. The Eigen vectors each of which is associated with a mode of voltage / reactive power are used to describe the mode shape and to provide information about the network elements and generators which participate in each mode. Using the bus participation factors, the weak load buses are identified. Real time prediction of voltage stability is applied in IEEE 30 bus system, the modal analysis technique was shown to provide an accurate estimate of the system’s proximity to voltage stability limit and consistently and correctly predict the critical buses and weakest branches in the transmission system.

Identification of weak buses and elements participation in voltage instability of large multi bus power system

In heavily loaded systems, voltage stability limit is usually dominant and voltage instability is usually observed following large disturbance. This is typically the case in the deregulated environment as the transmission systems are operating under more stressed condition due to increased transaction level associated with open access. In this paper simple voltage stability analysis is carried out for a multibus power system (26 bus system) using V-Q sensitivity analysis and modal analysis. The bus participation, line participation and generator participation in critical mode of voltage stability is determined. This is useful for implementation of contingencies in power system for further study of voltage stability. A novel idea of small increment in reactive power and distributing the same in proportional to bus participation factor for calculation of generator and line participation is presented. Also the correlation between the voltage sensitivity factor and bus participation factor is established for identification of weak buses.

Parks Are the Answer: Help Us Prove It

In just the last year I've seen several new fitness centers spring up in Pittsburgh, PA. But unless these centers sprout up in every neighborhood-with free memberships for all our citizens-they will never be the solution to our physical activity deficit. With a population of more than 300,000 inside our city limits, we need to be talking about ways to get tens of thousands of people more active. I'm not picking on fitness centers, just using that obvious example to illustrate the problem of translating activity programs to a meaningful scale. Is the activity scalable? When I read about programs designed to promote teen physical activity through exciting programs in canoeing-which bus participants miles from their homes-I have to wonder how that experience will translate into long term activity patterns. How many of the teens will be canoeing in 3 months or 3 years or 30 years? Is the activity sustainable?

Modal analysis of power systems to mitigate harmonic resonance considering load models

Abstract To detect and alleviate harmonic resonance in a power system have been a delicate issue. In this paper, the effect of load modeling on resonance behavior of power systems employing eigenvalue sensitivity analysis is investigated. The most influencing parameters to mitigate resonance modes are detected using the sensitivity of critical eigenvalues with respect to the network various components in a frequency range. Also, results inferred from the criteria of driving point impedance and bus participation factors are compared with those of the sensitivity analysis with different load models. Where to locate capacitors and filters to mitigate the resonance modes is obtained using these criteria. The methods are tested on the well-known New Zealand as well as IEEE-30 bus test systems. Simulation results are discussed in detail to investigate the methods’ efficiency and capability.

Secure communication in microcomputer bus systems for embedded devices

The protection of the microcomputer bus system in embedded devices is essential to prevent eavesdropping and the growing number of todays hardware hacking attacks. This contribution presents a hardware solution to ensure microcomputer bus systems via the Tree Parity Machine Rekeying Architecture (TPMRA). For this purpose a scalable TPMRA IP-core is designed and implemented in order to meet adaptability, low cost terms and variable bus performance requirements. It allows the authentication of different bus participants as well as the encryption of chip-to-chip buses from a single primitive. The solution is transparent and easy applicable to an arbitrary microcomputer bus system for embedded devices on the market. A proof of concept implementation shows the applicability of the TPMRA in the standardized Advanced Microprocessor Bus Architecture (AMBA) by implementing the IP-core extension into the peripheral AMBA bus-to-bus interface. It will be shown that the proposed solution is latency free and can be easy implemented into the AMBA bus interface bridge in order to protect the ARM bus system with a low hardware overhead considering all AMBA bus features.

A PRAGMATIC APPROACH TO VOLTAGE STABILITY ANALYSIS OF LARGE POWER SYSTEMS

This paper presents a methodology to perform voltage stability studies for large power systems. This methodology consists of both modal and time-domain analysis; results from both techniques are used in selecting and siting solutions for potential voltage instability or collapse. Critical contingencies, bus participation, and meeting a predetermined voltage criterion constitute the core of the process. Examples from a real study serve to illustrate different stages of the methodology.

Design of robust coordinated SVC supplementary controllers

Abstract A method for designing coordinated H ∞ SVC supplementary controllers is presented to improve the damping of interarea oscillations. A distributed controllers are designed considering overvoltage problem, which is thought to be a critical issue for SVC to design a supplementary damping controller. The proposed method contains a method to obtain dynamic equivalents of a power system model through an uncertainty minimization procedure. This method is aimed for realizing a tight design for distributed controllers so that a better performance of the total system can be gained. In addition, an uncertainty minimization process is used to regulate indirectly the controller's output so that the overvoltage problem is treated in the design step. The locations of SVCs are determined from the voltage stability point of view using bus participation factor. An effective input to damp oscillations is selected based on residue concept. The effectiveness of the proposed control design is demonstrated through nonlinear numerical simulations in five machine eight bus system under several critical operating conditions.

Use of participation factors in modal voltage stability analysis of multi-infeed HVDC systems

In recent works, a method based on the eigenvalue decomposition technique, known as modal analysis, had been applied to the voltage stability analysis of multi-infeed HVDC power systems. In this method, not only the critical eigenvalues are useful in evaluating the voltage stability of the system, but their associated eigenvectors also contain information on the most severe disturbances to the system. In this paper, the use of these modal information for such analysis is further exploited. In particular, bus participation factors are used to identify the critical AC communication bus for effective remedial measures to be implemented. The significant influence of power system parameters on the bus participation factors are also investigated.

Trends in Intelligent Instrumentation

Nowadays there are several application fields where the effective price per unit is the main criterion for instrumentation solutions. Especially the topological structure of such a system is appropriate to design suitable systems: Whereas in former times each (analog) sensor and actuator was connected to a central controlling computer by an own multi-wire cable there is an obvious trend towards fieldbus concepts with one ore more planes. The bus participants are smart sensors and actuators being possible to perform signal processing in a decentralized manner. One of the main reasons for this development is the progressing decrease of costs in the field of microelectronic components caused by improved technological methods. Examples of various spheres (monitoring of concrete constructions, decentralized air-condition, calibration of gas-sensors, instrumentation in automobiles) demonstrate promising realizations which are able to take the part of a pioneer in futural low cost automation techniques.