AC System Loadflow Analysis
There are currently 4 loadflow methods [NR, NR+, PQ, PQ+] available. NR stands for the Newton method, PQ for the Fast Decouple method. The + indicating addition features, including the following:
- Add a swing bus if necessary
- Turn-off all buses in an island if there is no generation source.
Loss allocation algorithm description could be found Here.
InterPSS currently supports three types of contingency analysis: N-1 Analysis; N-1-1 Analysis and N-2 Analysis.
- N-1 Analysis
Open each branch in the power network and run complete AC loadflow analysis for each contingency.
- N-1-1 Analysis
First open each branch in the power network and run complete AC loadflow analysis for each contingency. Then for each N-1 contingency, open each branch with branch Mva rating violation and run complete AC loadflow analysis for each N-1-1 contingency.
- N-2 Analysis
Open all combination of two branches in the power network and run complete AC loadflow analysis for each N-2 contingency.
The following three reports are generated after the analysis:
- Non-converged Case
Non-converged loadflow case [ tolerance: 0.0010 pu ]
Case Max Error Info
[x]Bus120->Bus200(1) dPmax : 0.00967(pu) at Bus : Bus141, dQmax : 0.01829(pu) at Bus : Bus265
[x]Bus1010->Bus1(1) dPmax : 11.86389(pu) at Bus : Bus1010, dQmax : 4.40034(pu) at Bus : Bus1020
The non-converged case report listed all cases with non-converged loadflow against the tolerance. InterPSS use a non-diverge loadflow algorithm, which guarantees that the loadflow will never diverge.
- Voltage Margin
Bus Voltage Limit: [1.10, 0.85]
Bus Id LowVolt LowMargin Description
Bus340 0.8774 2.7% [x]Bus110->Bus280(1)
Bus141 0.7850 -6.5% [x]Bus110->Bus280(1)
Bus140 0.8437 -0.6% [x]Bus110->Bus280(1)
The voltage margin report lists the lowest voltage for the bus for all contingencies and compare it with a Bus Low Voltage Limit. The description tells which contingency caused the lowest voltage. For example, [x]Bus110->Bus280(1) indicates that the open branchBus110->Bus280(1) contingency caused the lowest voltage.
- Branch Mva Margin
Branch Id MvaFlow MvaRating P + jQ Margin Description
Bus260->Bus263(1) 56.2 65.0 ( 53.4+j 17.4) 14% [x]Bus110->Bus280(1)
Bus151->Bus150(1) 369.0 300.0 ( 362.0+j 71.4) -23% [x]Bus111->Bus110(1)
Bus111->Bus110(1) 378.3 150.0 ( 368.0+j 87.9) -152% [x]Bus151->Bus150(1)
The branch Mva margin report lists the most severe branch Mva rating violation, indicating with a - sign. The description tells which contingency caused the most severe branch rating violation.
- A 115-bus system (right-click and Save link as ... to download) in PSSE V30 format
- IEEE 14-bus system in IEEE CDF format
- IEEE 14-bus system in ODM format