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Industrial Research And Turbine Plant Modernization Laboratory
Main / Main Activities > Turbine Units Division > Steam Turbines Department > Industrial Research And Turbine Plant Modernization Laboratory

Main activities:

  • The laboratory conducts research and development of prospective turbine units of thermal and nuclear power plants, industrial research of operating steam turbines, develops and commissions the turbine equipment operation diagnostics system at thermal power plants.
  • Among of the significant significant solutions developed by the laboratory is the Forced Steam Cooling System (FSCS). The system is designed for extending the service life of turbine units and decrease the progressing bowing of HP and MP rotors in high-power steam turbines. SPPO has been commissioned since 1985 and by now has been installed in 65 turbine units of various power output in Russia and abroad. Over 30 years of operation have proven the reliability and efficiency of the system.
  • The other system – Mentor – is an integral part of the unified turbine unit diagnostics system. It allows calculating the efficiency of cylinders and monitor stress in hot elements of high-pressure cylinders (HPC) and intermediate pressure cylinders (IPC).
  • Modernization of thermal cycle of turbine units to prevent the abrasive and erosive wear of the blade row in HPC and IPC.
  • Modernization of thermal circuits of process heat discharges into the exhaust part of LPC to increase strength of stellite plates of rotor blades in the last stages of K-300 turbines.
  • Development of HPC cooling project for the new turbines T-295/335-23,5 to increase their efficiency at low-flow operating modes of turbine units.
  • Forced Steam Cooling System (SPPO)

 Layout of cooling steam feed to the intermediate pressure rotor (IPR)

(applicable for turbines T-100-130, T-250-240, K-200-130, K-300-240, K-500-240)

Layout of cooling steam feed to HPR and IPR (applicable to turbines K-210-130 (LMZ), TPP Maritsa-Vostok-2)

Temperature fields of the IPR of turbine K-660-247 LMZ at the nominal load:

a)  – no cooling, b)  – with SPPO activated

  • Improvement of Performance Characteristics of Steam Turbines by Modernizing the Cylinder Support System

Modernization of the steam turbine support system is a replacement of conventional solid key by a split-type key.

Modernization purpose: normalization of turbine expansions that allows to improve operational characteristics of turbine plant:

  • improve vibration state of turbine in intermittent operation modes;
  • normalize expansion ratio of high and intermediate pressure rotors;
  • reduce deformation of guide bearing housings and foundation cross beams;
  • increase start/stop characteristics of turbine – reduce the starting time from different thermal conditions.

Currently, there are 16 K-200, K-300 turbines in operation equipped with modernized support systems.

  • To further improve the expansion characteristics of steam turbines the split-type keys may be supplemented by special devices – pushers

The experience in extended operation of 200–300 MW turbines in industrial applications, where turbines are fit with split-type keys produced by NPO CKTI, is the evidence of significant improvement and normalization of thermal expansions, which result in improvement of performance characteristics. Besides, this improves the vibration characteristics of the turbine in variable-load operation, reduces the deformation of guide bearing housings and torsion of foundation girders, improves free expansion of cylinders and their return to the default position when cooling down.

  • Moisture removal from the flow path and labirinths of LPC of K-200-130 turbines

Localization of erosion damages and condensation surfaces at the output stages of a conventional LPC

Рис.2. Erosion-resisting devices in the last stage diaphragm ande the LPC hood in K-200-130 turbine:

1.Shielded baffle with inter-tier sealing located inside;

2.Inter-tier sealing;

3.Moisture-collecting collars;

4.Drain holes;

5.Drain tube;

6.Streams of condensate to be drained


The crucial factor lowering the operating reliability of LPC in K-200-130 turbines consists in erosion damages of blades:

  • through erosion of trailing edge by the base of the top tier blades at penultimate (Baumann type) stages, which leads to formation of fatigue cracks and vane ruptures;
  • intense erosion wear of blade tips at the last stages, reducing their service life due to the need for replacement, since the chord reduces beyond limits.

The primary source of moisture turned out to be intense condensation of steam on the internal surface of the cone-shaped input baffle at the last stage diaphragm. The baffle is washed on the outside by colder (~ 24 °C less) exhaust steam of the top tier (see the figure).

To prevent erosion damages, the laboratory suggests the following procedures:

  • correctijn of axial clearance Δ in the inter-tier sealing or its restoration (see the figures)
  • shielding and draining of internal con-shaped and cylindrical baffles of the last stage diaphragm
  • Remote temperature control of steam emission and air inflows in end seals

In practice, the steaming process is analyzed visually or through assessing the water content in oil, while the air inflows – by the decreasing vacuum in the condenser. NPO CKTI JSC has developed and successfully implemented on many power plants the method of remote control of steam emission and air inflows in end seals of turbines.

The suggested end seal operation control method is based on measurement and comparison of temperatures of air-steam mixture tas, sealing steam ts and the ambient air ta (see the figure).

The “mandatory” condition of absence of steaming and air inflows: ta < tas < ts.

The “sufficient” condition looks like this: ta + Δt1 < tas < ts – Δt2 or tп – Δt2 > tas > ts − Δt3.

Here, Δt represents settings, the values of which are determined through experiments. Settings determination method is the «know how» of this proposal. The introduction of end sealing monitoring is expected to decrease the air inflows, which is equivalent to deepening of vacuum by at least 0.1 %.

  • Modernization of R-type turbine units with the aim to make them work in the cogeneration cycle instead of back pressure mode

Modernization purpose – recommission of reserve R-type turbines that have a large economic life.

  • Modernization of R-50-130 turbine units does not only allow its operation according to the cogeneration cycle in a wide load range, but also improves the overall plant economic performance.
  • The conducted heat and strength evaluations have allowed determining the optimal conditions of turbine operation from the perspective of its structural reliability and efficiency.
  • The modernization allows reaching to the previous operating mode of the turbine, which requires a shutdown for several hours.
  • Information Diagnostics System Mentor

The purpose of Mentor system

  • Evaluation and display of optimal start/stop look-ahead schedule for the turbine plant based on its factual thermal condition
  • Diagnostics and analysis by:
    • performance of end sealings;
    • quality of turbine extensions;
    • thermal state of shells and flanges.
  • The evaluation of equipment repair and operation quality in all operating modes
  • Display of thermal stress levels in HP and IP rotors and shells
  • Real-time display of thermal stress levels in HP and IP rotors and shells
  • Evaluation of accrued total fault probability rate (service life spent) of HP and IP rotors
  • Selection of optimal boiler operating mode that ensures the optimal boiler efficiency (MEI software).

Thermal Stress Calculation

Efficiency Calculation