 Evaluation  |
|
|||
|
||||
| Loads and Load Cases Evaluation | Most design procedures for wind turbines
are based on a structural dynamic model. Structural dynamic simulations are
used because they can account for all the steady and unsteady aerodynamic
loading, inertia loading and control induced loading simultaneously. It is
impossible to account for all these factors with simple design calculations.
However, these models can be very complicated and often require some level
of validation before the designer can use them confidently to predict
fatigue and extreme loads. Test data is commonly compared with simulations
of the corresponding test conditions. This load verification process also
gives the certification body confidence in the process used to develop the
rest of the predicted loads. Documentation of the structural dynamic model
verification has become an important part of most certification
requirements. A loads document should contain all the critical static and fatigue loads for plausible combinations of external conditions and operating conditions defined in IEC 61400-1. The load distributions should be determined for the blades and all critical load paths within the structure. The electrical loads, fault loads and any control-induced loads should also be calculated for all possible operating conditions. This loads document should be a living document. It should include results from field tests, which support the predicted loads. As the machine configuration changes this document should be updated to account for any load changes. The certification body will review this document for accuracy and thoroughness. NREL has assembled a guideline to help prepare a loads document. Refer to the Guidelines section at the top of this web page and look for DG01 "Loads Guideline".|| Contents || |
|||
| Control & Protection System | The control
and protection system should be documented in a way that clearly illustrates all possible
faults and demonstrates how the protection system functions to prevent catastrophic
failures. This might include control logic diagrams, fault trees, failure modes and
effects analyses, test results of the control system when subjected to simulated faults
and tests of any mechanical backup systems. NREL has
assembled a guideline to help prepare a Control and Protection document. Refer to the
Guidelines section at the top of this web page and look for DG05 "Control and Protection Guideline".
|
|||
| Structural Component Design | The structural
design of all components should be documented. Appropriate material properties should be
used along with the static and fatigue loads, taken from the loads document, to evaluate
the structural integrity. Component tests can be used to support design calculations. If
the component tests simulate all possible design load, load distributions, static and
fatigue loads throughout the life of the machine, it may be possible to substitute the
component tests for analysis. NREL has
assembled a guideline to help prepare structural strength documents. Refer to the
Guidelines section at the top of this web page and look for DG02 "Strength Guideline".
|
|||
| Mechanical & Electrical Design Document | Mechanical and
electrical devices such as gearboxes, actuators, bearings, electrical contactors and
controllers must be sized to accommodate the loads they are subjected to throughout their
service life. This document must contain a translation of the general turbine loads into
component loads for each of the specific devices and document the performance of the
device when subjected to these loads. Analysis results or manufacturers specifications can
be used to demonstrate component serviceability. For critical components bench tests
simulating the wind turbine application are recommended to demonstrate component
performance. Performance and geometrical specifications are a good basis for a quality
agreement between the manufacturer and the supplier and are generally required for the
manufacturing quality plan. These performance and geometrical specifications should be
part of this Mechanical and Electrical Design Document. || Contents || |
|||
| Component Tests | This element
can by used to verify the design performance of a machine component such as a blade, gear
box or pitch system. Component test data are most often used when the analysis of the
component is difficult to accomplish with confidence. They can be used instead of an
analytical approach if all the component design loads can be accurately simulated in a
bench test. Usually this is not possible, so the test data are used to verify specific
design cases and the model is then used to simulate the complete set of design loads. Wind
turbine blades are almost always tested for design verification. |
|||
| Design Control Quality Plan | The design
process is the first stage of a product's life. During this stage the wind turbine will
constantly change and mature. As the changes occur design loads will be impacted,
manufacturing procedures will change, and operation and maintenance procedures will
change. There must be a system of controlling and documenting these changes so that their
impact on other parts of the turbine design are accounted for appropriately. Such a Design
Control Quality System might include Engineering Change Orders which are approved by the
engineering organization, manufacturing organization and Operation and Maintenance
organization before the change is implemented. Documentation of this system is an
important part of the certification review since it demonstrates the use of an engineering
development process. || Contents || |
|||
| Manufacturing Plan | Manufacturing
processes will be affected by changes in the design to meet installation and user
requirements. Because manufacturing processes can affect system and component integrity,
reliability, and performance, the manufacturing plan must be continually up-dated and
controlled to consider these factors. Wind turbine components and subsystems are commonly
fabricated in a number of dispersed locations before being assembled at a central
location, which may be at the installation site. This makes it particularly important to
have an up-to-date manufacturing plan. NREL's evaluation of this plan will factor in all
previous elements of the design process. |
|||
| Installation Quality Plan/Manual | A turbine is
not a complete operating system when it leaves the factory floor. The machine must be
installed in the field. The same machine could be installed anywhere in the world by
different installation crews. Very often local building requirements may impact the final
turbine configuration. To guarantee that the turbine will perform as specified in the
design documentation it must be installed to meet the original design specifications. The
Installation Quality Plan/Manual should contain all specifications and procedures needed
to properly install the machine. |
|||
| Maintenance Manual | Many component
performance predictions are based on the assumption that maintenance will be performed at
specified intervals. If this maintenance is neglected or improperly done it can impact the
safety and performance of the turbine. This maintenance will be conducted by different
crews throughout the world. They will certainly be trained but they may not be trained by
the original designers. To make sure that maintenance is performed properly a maintenance
manual should describe all aspects of the required maintenance. NREL will review these
maintenance specifications to make sure that they are consistent with the design
assumptions. |
|||
| Operations Manual | The designers
base their predicted performance on specified operating procedures. Many machines can fail
if operated improperly. This manual should contain specifications for safe start up,
shutdown, access to critical parts, emergency procedures and procedures for the general
control of the machine. NREL reviews the Operations Manual to assure that the operating
procedures are consistent with the design assumptions and that they are clear to intended
wind turbine users. |
|||
| Personnel Safety Manual | NREL reviews and evaluates the installation, operation and maintenance manual(s) provided by the wind turbine manufacturer using applicable safety requirements/guidelines contained in the IEC 61400 series of standards. | |||
| || Contents || | ||||
| || Home || Certification || Testing || Evaluation || Standards || Information || | ||||
|
||||
Prepared by Updated: November 21, 2002 |
||||
