We call an electric generation mechanism, whose working fluid is water, as a steam turbine cycle or Rankine cycle. A steam turbine cycle has been adopted in fossil-fuel or nuclear power plants because it is suitable for large-scale and continuous operation. To check the performance level of a steam turbine cycle, performance tests are carried out according to the performance test codes (PTCs) provided by the authorized institute. However, authors found that it was too difficult to follow the PTCs in actual plants. The reason is signal reliability and the prerequisites of the PTCs. The effort to overcome these shortcomings already started and some commercial solutions were also developed. These solutions include a general-purpose simulation code with signal validation techniques. Despite these achievements, performance engineers are suffering from the inconsistency between their previous performance analysis work and new performance analysis tools. This study proposed the solution, a need-oriented turbine cycle simulation toolbox, which is another general-purpose simulation code with the signal validation method based on multivariate statistics. This toolbox removed the inconsistency by customizing the actual needs of performance engineers. The accuracy of the developed simulation code was validated with other commercial turbine cycle simulation codes.