The symmetrical component method used by elec calc™ for the calculation of short-circuit currents allows a very accurate calculation of these currents according to the characteristics of each motor and this at every point of the installation, and for each of the operating scenarios described in the project.
A reminder of the requirements:
The standard IEC 60909-0 and its French equivalent NF EN 60909-0 “Short-circuit currents in AC three-phase networks” specify:
“Medium and low voltage motors contribute to the initial symmetrical short-circuit current, the peak short-circuits current, symmetrical short-circuit current cut and for asymmetric short-circuits, also to the permanent short-circuit current. The medium-voltage motors must be taken into account when calculating the maximum short-circuit current. Low-voltage motors must be taken into account in plant auxiliaries as well as in industrial installations and the like, for example in the networks of the chemical and iron and steel industries, and in pumping stations (…)
(…) It is permissible to overlook the contribution of asynchronous motors to the short-circuit current in low voltage supply networks if their contribution does not exceed 5% of the calculated initial short-circuit current. without motors (…)
(…) In the calculation of short-circuit currents, it is allowed to overlook these medium and low voltage motors, when, in accordance with the circuit diagram (locking) or the operating process (reversibility), they are not in use at the same time.”
In order to meet these requirements, some guidelines (PD CLC / TR 50480 or FD C 15-500) provide a comprehensive approach that leads to increasing the maximum short-circuit currents of the plant as a function of the ratio of the total power of the motors running simultaneously and the total power of the sources.
This approximate approach is, of course, conservative and fastidious to implement if the installation comprises several operation modes with different sources.
To overcome this difficulty and improve the accuracy of the results, elec calc ™ 2018, thanks to its real-time calculation possibilities, offers the user the choice for each motor whether or not it participates in short circuits.
By Philippe Aupetit – Product Manager for elec calc™2018 software
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The complexity of electrical calculations is a major issue nowadays and without an appropriate software are impossible to even imagine. elec calc™ is the CAE software solution dedicated to the sizing of electrical installations, the only one in the world that allows integrating the management of high and low voltage in the same project and in compliance with international standards (IEC, NF C 15 -100, RGIE/AREI…).
Which are the industries this software tool can be used? Which are the benefits?
elec calc™ facilitates the best design quality and shorter development time with increased productivity along with standardization. Overall design accuracy is guaranteed to ensure correct sizing of high and low voltage electrical installations.
- Exceptional calculation performance in real-time
- Automatic sizing feature to optimize the design
- Single-line diagrams (synoptic and folios) exploitable to the AutoCAD® format
The quality of the power supply and validation of calculations according to various international and national standards is important, that’s why elec calc™ incorporates these key requirements according to the selected standards.
- Cost reduction and energy saving on designs of installations
- Ensures optimum sizing and verifying the installation
elec calc™ suite is composed by a range of software applications that ensures optimal sizing of the installation and proper maintenance throughout the installation’s life cycle: from design, works supervision, commissioning, operation, maintenance, and dismantling.
- Flexible editing, exporting and printing functions
- Time-saving personalization features
It is essential to ensure the correct behavior of critical facilities such as hospitals, data processing centers or facilities in mining, with elec calc™
- Management of the geographical structure of the installation and relevant environment parameters
- Management of operating modes to simulate and control different installation configurations (normal operation, standby, maintenance…) and guarantee security
With elec calc™ save money and reduce costly errors in the design process with the quick selection of manufacturers’ or users’ references and verification of installation sizing. This robust software offers critical calculations for factors such as earthing systems, cable ampacity, short circuit currents, thermal stresses, voltage drops and discrimination studies between protections are key, for the continuation of supply.
A good discrimination study allows the coordination of different protections at different levels of the installation, to guarantee the continuity of supply and service within critical installations in case of failure (short circuits and overloads).
HVLV in One Solution
elec calc ™ is designed to manage installations with multiple voltage levels, both HV and LV in the same project, in alternating current for frequencies of 50 or 60 Hz. The full calculation of the installation is carried out each time a change is made to the installation.
elec calc™ is a unique electrical software which allows the use of all possible source types including UPS in all operating modes. Also, it allows the use of all possible types of receivers as well as capacitors for reactive power compensation.
Using this software solution will reduce design times for projects while simultaneously reducing project costs.
elec calc™ provides engineers, installers, developers, energy producers/distributors and manufacturers with a powerful tool for sizing electrical installations. Within the field of design and calculation, we help ensure the rapid development of your projects and high-quality electrical calculations are essential in today’s marketplace.
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