IEEE Std 693-2018 pdf free download – IEEE Recommended Practice for Seismic Design of Substations.
The recommended practice contains recommendations for the seismic design of substation buildings and structures, and the seismic design and qualification of substation equipment.
1.2 Purpose
This recommended practice is for new substations and planned additions or improvements to existing substations. It is not intended that existing substations must be retrofitted to these recommended practices. Instructions on how to include this recommended practice in specifications are provided. IEEE Std 693™ is designed as an integrated set of requirements for the seismic qualification of electrical power equipment. Users should use IEEE Std 693 without modification or removal of any requirement, except as allowed herein.
1.3 General
This recommended practice provides minimum requirements for the seismic design of substations and seismic qualification of equipment. Emphasis is on seismic qualification of electrical equipment and its anchorage. Instructions on the use of this recommended practice is provided in Clause 4. There are several important goals of this recommended practice; one is to provide a single standard set of design recommendations for seismic qualification of each equipment type. Design recommendations consist of seismic criteria, qualification methods and levels, structural capacities, performance requirements for equipment operation, installation methods, and qualification documentation. The intent of a uniform and consistent seismic qualification procedure is to enable manufacturers to incorporate seismic criteria into their design process and reduce the cost for qualification of substation equipment. Manufacturers can qualify their equipment once for a given qualification level and reduce the need for specialized testing. It should also improve earthquake performance by establishing clear performance criteria that take into account the dynamic characteristics of substation equipment.
Another goal of this recommended practice is to allow the user, or user’s agent, to secure substation equipment that will have no significant structural damage and maintain electrical functionality at nominal operating conditions during and after a seismic event as specified herein. This recommended practice establishes three qualification levels for earthquake performance. They are low, moderate, and high qualification levels. The user is required to determine the qualification level when purchasing the equipment.
1.4 Associated design references
1.4.1 Electrical connections between equipment The design and implementation of electrical connections between equipment should be in accordance with the recommendations of this recommended practice and IEEE Std 1527™.
1.4.2 Electrical equipment Electrical equipment and their associated anchorage should be designed in accordance with the requirements given within this recommended practice and ASCE 113.
1.4.3 Dedicated support structures Dedicated support structures, which are qualified together with the equipment, shall be designed in accordance with the requirements of this recommended practice as prescribed by the methodology used to qualify the supported equipment. All other support structures may be designed in accordance with this recommended practice or the requirements given in ASCE 113. Connection of the equipment to any support structure shall be designed in accordance with the requirements of this recommended practice.
1.4.4 Primary substation structures The seismic design of primary substation structures, (e.g., strain bus structures, A frames, rigid bus structures, etc.) is beyond the scope of this recommended practice and should be designed in accordance with the requirements given in ASCE 113. The anchorage of substation structures should be designed in accordance with ASCE 113.
1.4.5 Foundations Foundations are designed to have an adequate load capacity with limited settlement and lateral displacement by a civil or geotechnical engineer and the footing itself may be designed structurally by a civil or structural engineer. The primary design concerns are settlement and bearing capacity. When considering settlement, total settlement and differential settlement are normally considered. Foundation loads from the equipment may be designed in accordance with 6.6 or to the requirements of the relevant code in the jurisdiction of the utility and/or substation.IEEE Std 693 pdf download.