Whitepapers

Selecting Outdoor Enclosures for Utility and Smart Grid Electronics

10/15/2012

Communication electronics, SCADA equipment, and batteries deployed along Transmission and Distribution line will require protection from the elements, thermal management to maintain the proper operating temperature ranges, and security to prevent malicious access and tampering. This white paper introduces utility operators to the relevant features and capabilities of enclosures, including the range of thermal management systems, power efficiency, acoustic management, security and intrusion prevention, and scalability and flexibility.

Fact or Fiction- benefits of inhibited verses uninhibited hydrocarbon oil for transformers

09/27/2012

Contents:

-Uninhibited and inhibited (naphthenic and iso-paraffinic) hydrocarbon transformer oils.

-Typical product features/benefits, and how these can be tested, assessed and improved, using examples from the latest generation of Shell products.

-Transformer manufacturers and utility companies – perceptions and findings from the field.

-Laboratory performance evaluation of the two product types, primarily in terms of oxidative stability. For mixed and pure uninhibited and inhibited oils.
 
-Shell recommendations on how to obtain maximum oil performance benefits.

-Conclusions - review of the relative merits of the two product types and confirmation of the benefits of inhibited versus uninhibited products.

 

Study and Design Considerations of HRSG Evaporators in Fast Start Combined Cycle Plants

09/24/2012

Large heat recovery steam generators (HRSGs) are increasingly
required to be designed for cyclic operation and also required to meet faster startup
times. The ability of horizontal HRSGs cyclic operation has been discussed and
widely reported in literatures and studies. However, the operation and design life of
HRSGs become more important when the system is operated with fast startup
times.This paper deals with the effect of fast startups on evaporator design and looks at the impact to the overall design and operation of the HRSG. The paper provides a comparison to traditional startups, explains the need to verify the design of evaporators for fast startups, and analyzes design issues.

ASME and EuroNorm Compared for HRSG Design

09/24/2012

Recently CMI completed a Heat Recovery Steam Generator for a 400 MW standard block CCPP in France, for which ASME code was used for the HRSG design. Regarding that project, CMI conducted an internal review based on the EuroNorm instead of the ASME code. The purpose of this exercise was to study and compare advantages and design features of ASME code versus EuroNorm. This paper presents the conclusions of the comparison and review that were undertaken.

Application of CFD Modeling in HRSG Evase Design

09/24/2012


The paper presents work done to develop a CFD model for analyzing the velocity and temperature distribution of HRSG systems with a single angle roof, a dual angle roof, and an air flow optimized evase. Particularly, attention was given to the critical areas of the HRSG, which include the evase, the first heat exchanger bundle, and upstream and downstream of the duct burner. On the basis of the all analyses, the air flow optimized evase was found to be very effective in establishing a uniform velocity distribution into the first heat exchanger bundles (superheater 3 and reheater 2) and in reducing the pressure drop through the whole HRSG system, which is of benefit to gas turbine operation.

Cycling Tolerance - Natural Circulation Vertical HRSGs

09/24/2012

Combined cycle plants must supply electrical power to the grid as and when needed with consequent day/night and weekday/weekend cycling. Plants have to come on and off line with minimal notice and sometimes run at partial loads. European vertical HRSGs designed to permit the tubes to expand and contract freely and independently are able to minimize fatigue stresses related to cycling. This paper presents solutions to HRSG design issues for cycling tolerant operation. It relates to published data on problems observed with cycling horizontal HRSGs, and it describes how these problems can be overcome. Concepts, design features and calculation methods applied to cycling tolerant HRSGs are reviewed in detail.