Power System Transient Security Quantitative Analysis Software FASTEST

Power system transient security quantitative analysis software FASTEST(Fast Analysis of Stability using the Extended equal area criterion and Simulation Technologies)is developed by Nanjing Automation Research Institute (NARI). It is designed to meet growing challenges of the power industry in a deregulated and open-access environment. It can quantitatively assess the transient angle stability, transient voltage security, transient frequency security and transient damping security of power systems. It can satisfy the need of off-line and on-line dynamic security analysis.

1  Algorithm and Model

• Powerflow calculation adopts P-Q decomposition method and Newton-Raphson method.
• The basic algorithm of stability calculation is: solving by trapeziform integration method after linearizing all the differential equations; solving network equations iteratively after the delta decomposition of admittance matrix or by Newton method.
• Quantitative analysis of transient security adopts EEAC method and voltage/frequency quantitative assessment method.
• FASTEST can deal with all the models of BPA powerflow and stability analysis programs.
• FASTEST can deal with all the fault types of BPA stability analysis program.
• FASTEST can deal with powerflow and stability data of BPA format.
• FASTEST can deal with powerflow and stability data of PSASP format.

2  Computation Scale

• 6000 buses;
• 10000 lines, including 200 On Load Tap Changers and 50 phasers;
• 60 power interchange areas. Each area can contain maximum 10 zones. All areas can contain maximum 150 zones. It allows maximum 500 power interchange tie-lines among areas;
• 1000 generators;
• 20 two terminal DC links and 50 multi-terminal DC links.

3  Analysis Function

• Providing margin of transient angle stability, transient voltage stability, transient voltage/frequency deviation acceptability and transient damping security after one time-domain simulation. Margin zero indicates that the system is critical stable of transient angle, transient voltage, transient voltage/frequency deviation acceptability and transient damping. Positive margin indicates that the system is secure. Negative margin indicates that the system is insecure. The larger the margin is, the more secure the system is.
• Determination of unstable mode and potential unstable mode, critical mode and potential critical mode.
• Limit search strategy guided by sensitivity.
• Early termination of time-domain simulation.
• Fast computing Critical Clearing Time (CCT) of transient angle stability, transient voltage stability and transient voltage/frequency deviation acceptability.
• Fast computing the limit load power of transient angle stability, transient voltage stability and transient voltage/frequency deviation acceptability, tie-line limits, generator limits and critical load shedding value. The redistribution mode of loads and generators can be assigned in advance and automatically processing during search. 
• Fast computing the minimum reactive power compensable value of transient angle stability, transient voltage stability and transient voltage/frequency deviation acceptability.
• Providing unstable mode portrait changing with fault clearing time.
• Automatic optimization of emergency control strategies (independent software kit OCDT).
• Fast scanning and ranking of all the fault tables or specific fault table in order to satisfy the different needs of screening and reliably select serious faults.

4  Other Features

• Friendly Man-Machine Interface.
• Conveniently modifying operating condition.
• Automatically forming flexible setting fault table.
• Manually assigning the upper limit of the limit's errors.
• Simulation result curves and abundant quantitative messages of powerflow and security analysis.
• Critical stable trajectory and critical unstable trajectory.
• Phase portrait and extended phase portrait.
• Network geography diagram, single-line graph and powerflow on graph.
• Database management.

5  Computation Speed

FASTEST has achieved very good computation speed. The following table shows the CPU time required for some typical computations. Timing was taken on a PC that has the CPU of PIII666MHz and SDRAM of 256MB. The scale of the system is 57 generators and 520 buses. All the computations are under detailed model. The observation window is 6 seconds, the integration step is 0.01 second, and the upper limit of limit's error is set to be 5%.

Table CPU time requirements for typical computations by FASTEST

6  Computation Precision

The results of FASTEST powerflow and security analysis are consistent with the results of BPA program.

7  Engineering Applications

On-line dynamic security analysis

• Northeast China Electric Power Dispatching and Communication Center, Liaoning Electric Power Dispatching and Communication Center
• On-line projects of international famous EMS provider: US ESCA, ABB and GE

Off-line dynamic security analysis

• Northwest China Electric Power Dispatching and Communication Center, State Power South Company
• Shandong, Fujian, Shanxi, Sichuan, Jiangxi, Hunan and Guangdong Electric Power Dispatching and Communication Center
• Shanghai Electric Power Dispatching and Communication Center
• Fujian, Zhejiang and Shanxi Central Test and Research Institute
• North China Electric Power University (Beijing)
• North China Electric Power University (Baoding)
• State Electric Power Dispatching and Communication Center (tryout)

Consulting and research

• Research of Three-Gorge's transmission stability problems and the measures to improve stability
• Research of South Power network's stability problems and the measures to improve stability
• Establishment of the generator excitation and governing system's model and research of Tianguang HVDC system's security
• Verification and analysis of Hunan network 2002 operating mode's security
• Analysis of Shandong Dafen aluminum factory 110KV independent power supply system's security and research of relevant problems
• Research of multi-infeed HVDC transmission system's control strategy and its effect to the South Power network's transient angle stability
• Optimization of the Liaoning network's under-frequency and under-voltage load-shedding settings