SES Canada
Contact Us
Graphical Analysis and Design of Lightning Shielding Systems for Complex Geometries
SESShield-3D is a powerful software package for the analysis and design of lightning shielding protection systems for complex 3D environments, including substations, power plants, industrial plants and other such installations, accounting for the presence of power lines, equipment, buildings, etc. SESShield-3D allows arbitrary metallic structures to act as shielding systems, including not only shield wires and masts, but also other structures that attract lightning.
SESShield-3D offers a simple and intuitive user-interface that can be used to carry out a complete lightning shielding analysis for a system of freely positioned objects having various geometrical shapes, such as catenaries, cylinders, cones, cubes and other prisms. Furthermore, calculations are extremely rapid and provide clear, interactive, 3D graphical feedback, so that a shielding system can be designed very quickly.
SESShield-3D Main Interface – The main interface is split into two panels. The left panel gives quick access to the characteristics of each element in the geometry and the right panel is devoted to display 2D and 3D views of the geometry to analyze.
Technical Highlights
SESShield-3D can analyze and design a lightning shielding system for the protection of vulnerable systems of arbitrary geometries. SESShield-3D can also assess the probability of failure of a lightning protection system, accounting for the statistical distribution of lightning in the area of the system to be protected.
Four Shielding System Positioning Methods (SSPM) are presently supported by the program. These methods are described in the pertinent IEEE [1] and IEC [2] standards and include the Electrogeometric Model (commonly implemented as the Rolling Sphere Method) and variations thereof, the Eriksson Electrogeometric Model, which takes into account the height of the structure, the Protection Angle Method and the Mesh Method. Other methods are also regularly added, the next one in line being the Collection Volume Method whose implementation will be finalized shortly.
SESShield-3D supports the Rolling Sphere Method which is based on the Electrogeometric Model for assisting you with the positioning of a protection system on structures and around electrical facilities. Several variants for calculating the size of the rolling sphere are available: you can either specify the Striking Distance or the prospective stroke current, or select a lightning protection level. Another possibility consists in specifying the minimum Basic Impulse Level and the Surge Impedance of the equipment in a given area of a substation.
The program uses an object-oriented approach to describe the geometry that allows you to select, copy, paste and delete the objects. SESShield-3D is released with an object database, which allows you to insert fully constructed objects in the system to be analyzed or to store your own objects for future use.
The geometrical characteristics of an object can be easily modified using the flexible Properties window. CAD operations, such as duplicating the selected objects using the keyboard or moving and rotating them in the graphical space using the mouse pointer are typical functionalities that will help you quickly generate the system to analyze.
You can interact with the view of the model using the mouse to rotate, pan or zoom in and out on any area of interest.
SESShield-3D offers the possibility to import geometries created with SESCAD (which can import DXF files) and saved as a MALT session file. Geometries defined in SESShield-3D can also be converted into a format readable by MALT and editable with SESCAD.
SESShield-3D is highly interactive and visual. Once you have specified the geometry of the system and all other basic numerical parameters, SESShield-3D makes efficient use of your graphics card to rapidly display in your working window all the volumes around your system from which lightning strikes to vulnerable equipment can originate. You can then make adjustments to your shielding system on the fly and immediately see how effective these modifications will be. The status bar at the bottom of the display alerts you to the presence of unprotected zones that you may not have noticed from your current view point.
A scenario report is produced once the requested computations are completed indicating the computation results according to the selected method and the protection status. A list of unprotected objects as well as unprotected area and the expected number of failures are provided if portions of the system are not properly protected.
SESShield-3D Graphical Output – The computation results can be displayed in solid (bottom left) or transparent modes, with the latter available in both multi-tone (bottom right) and single tone (top) renderings
SES-Shield
SES-Shield is a complement to the considerably more powerful SESShield-3D package, providing optimized lightning shielding system heights for substations, shielding performance estimates for substations and transmission lines, and detailed risk assessments in accordance with IEC 62305-2.
The substation and transmission line shielding analyses are based on the electrogeometric model (frequently called “the rolling sphere method”) specified in the IEEE 998, IEEE 1243 and IEC 62305 standards.
The main purpose of the design component of this software package is to assist the user in optimizing the location and configuration of shield wires and masts in order to prevent the exposure of energized conductors, busses and equipment to direct lightning strikes of excessive magnitude. The risk assessment module, for its part, provides a formal assessment of the risk of different types of loss pertaining to vulnerable structures.
Technical Highlights
The design component of SES-Shield is particularly suited to shielding substations made up of parallel bays. See the following figure, for example, which shows a substation bay, along which shield wires (dotted red lines) and masts (points a1,…,an and c1,…,cn) are installed. SES-Shield can handle such systems, whether shield wires or masts are to be used for protection. For more complex configurations, use SESShield-3D.
SES-Shield also explores two lightning protection failure mechanisms associated with transmission lines:
- Back Flashover: SES-Shield calculates the probability that a flashover will occur across the line insulators as a result of a lightning strike to transmission line structures or to shield wires to which they are connected.
- Shielding Failures: SES-Shield also calculates the probability that a large magnitude lightning strike will miss the shield wires or transmission line structures and terminate directly on the phase conductors. SES-Shield can help you by computing the optimal position of each transmission line shield wire for effective shielding of each phase conductor. The corresponding shielding angles between shield wires and phase conductors are also computed.
The risk assessment module integrated into SES-Shield allows you to assess the risks related to lightning strikes on a structure, based on a formal procedure set forth in IEC 62305. The risks include damage to the structure itself, its components and contents, and may also extend to the surroundings of the structure and even involve the local environment. This type of analysis can help in selecting appropriate protection measures that reduce risks associated with lightning to a tolerable level.
Complex Systems
Whereas SES-Shield allows you to rapidly design shielding systems for simple substation and transmission line geometries and carry out formal risk assessments, SESShield-3D provides you with the ability to model complex 3D systems and design lightning shielding systems for them.
| [1] | IEEE Std-998 - IEEE Guide for Direct Lightning Stroke Shielding of Substations |
| IEEE Std-1243 - IEEE Guide for Improving the Lightning Performance of Transmission Lines | |
| [2] | IEC Std-62305-1 Ed. 1.0 - Protection Against Lightning |