Sebuah turbin uap dilengkapi dengan control valve atau biasa disebut governor yang mempertahankan turbin uap berputar pada putaran nominalnya (3000 rpm) dengan cara mengatur banyaknya uap yang dialirkan ke turbin. Terdapat 2 mode operasi governor valve turbin di PLTU Banten 2 Labuan, yaitu single dan sequence. Salah satu parameter yang dapat dipakai untuk menentukan kinerja turbin uap adalah efisiensi isentropik.Semakin tinggi efisiensi isentropik turbin, semakin dekat kerja turbin dengan kondisi idealnya. Sampai saat ini, belum adanya penelitian yang membahas pengaruh mode operasi governor valve turbin ini pada efisiensi isentropik turbin. Analisis dilakukan pada turbin Unit #1 dan Unit #2 pada keadaan transien maupun tunak. Dari hasil analisis didapat efisiensi isentropik turbin #1 dengan mode operasi SINGLE adalah 78.07% sedangkan dengan mode operasi SEQUENCE adalah 79.82%. Sementara untuk #2 efisiensi isentropik turbin dengan mode operasi SINGLE didapat 74.30% sedangkan dengan mode operasi SEQUENCE 74.60%. Pengoperasian valve turbin dengan mode SEQUENCE memiliki efisiensi isentropik yang lebih besar.

A steam turbine is equipped with some control valves or commonly called governors which maintains the steam turbine rotating speed at its nominal speed (3000 rpm) by
regulating the amount of steam that is flowed into the turbine. There are 2 operating modes of turbine valves at Bante 2 Labuan Coal-fired Steam Power Plant, namely single
and sequence. One of the parameters that can be used to determine the performance of a steam turbine is isentropic efficiency. The higher the isentropic efficiency of the turbine, the closer the turbine works to its ideal conditions. Until now, there has been no research
that analyses the effect of this turbine valve operating mode on the isentropic efficiency of the turbine. The analysis was carried out on Unit #1 and Unit #2 turbines in both transient and steady state. From the results of the analysis, the isentropic efficiency of turbine #1 with SINGLE operating mode is 78.07% while with SEQUENCE operating mode is 79.82%. Meanwhile for #2 the isentropic efficiency of the turbine with SINGLE operating mode is 74.30% while with SEQUENCE operating mode it is 74.60%.
Operation of the turbine valve with SEQUENCE mode has a greater isentropic efficiency.