This kind of accessibility shall not be usable during normal operation or maintenance. Our engineers make sure that they design switchgear as per the customer needs, laws and quality standards. SWITCHGEAR AND PROTECTIVE DEVICES 2015 1 | P a g e Lecture Notes on ... arrangement calculation of fault MVA for symmetrical short circuits. Thus the customer benefits from extended planning security and a cost-optimised solution. Learn about power engineering and HV/MV/LV substations. System Equipments, Distribution Transformer . Clearance Calculation in Air Insulated Substations: All the required minimum distances throughout the whole substation can now be automatically determined based on the 3D substation model processed by the Phase Checker. Back-up supply is then effected through the medium voltage network. The switchgear needs to be able to break and connect generators to load banks or to the grids. A common feature of all the network concepts presented is the radial operating mode of the distribution cables, which not only facilitates simple operational management (apart from the exception mentioned above) but also a simple protection strategy and troubleshooting, particularly with single phase faults (earth faults / short-circuits to earth). Switchgear types in locations with no access from the public, outside closed off electrical operating areas. It helps you. Tools and precise work instructions are needed to open the compartment, for example including a safety note. Although the incidence of an internal fault (arc fault) is very unlikely in type-tested air- or gas-insulated switchgear, the consequences of such an arcing fault may be severe for the operating personnel as much as for the room itself. Consumers classified according to importance and assigned to service continuity requirements placed on the grids. 1 pa electrical technical documents. This electrical installation handbook, ho-wever, aims to supply, in a single document, tables for the quick definition of the main parameters of the components of … with NEPLAN) in order, for example, to take account of the contribution of motor loads to the short-circuit current or to be able to formulate requirements for … Tables: – Overview of the rated values and selection parameters for the confguration of medium-voltage switchgear. with NEPLAN) in order, for example, to take account of the contribution of motor loads to the short-circuit current or to be able to formulate requirements for network protection. University of California San Francisco Medical Center Design Guidelines June 2015 Electrical 3 Section 26 - Electrical I. I am learning more about these MV stuffs. Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! Definition of planning principles and criteria, Technical and commercial comparison of the network varianrs, and, Expected average interruption duration (in min or h), Expected energy not supplied on time (in MWh/a), SAIFI (System Average Interruption Frequency Index): Expected average interruption frequency in 1/a), SAIDI (System Average Interruption Duration Index): Expected average non-availability (in min/a). average <35℃ 1 month average <90% Design and Installation of Medium Voltage Switchgear (Facts You MUST Know), Electrical engineer, programmer and founder of, Standards for the Design and Installation of MV Switchgear, Service continuity during work in progress, Estimation of pressure effects according to Pigler, Finite-elements-simulation of pressure load under conditions of arcing, very short tripping times from fast-acting relays, When an accessible compartment of the switchgear is opened…, The busbar and therefore the complete switchgear must be isolated, No partition plates within the panel, no panel partitions to the adjacent panels, Only the supply cable must be isolated. • Calculation of HT Current for CT KVA/11KV/1.732 • Example:-Transformer rating ( HT current for CT/PT selection) 500Kva/11KV/1.732 = 26.24 ... Standard Pipe & Plate Type Earthing Design for the 11 11 Kv Kv. Frequently, the background conditions dictated by the network operator’s supply function no longer correspond to the background conditions against which the medium voltage networks were established and expanded. For this reason, appropriate measures in relation to the room situation must be provided for pressure relief. General Requirements 1-5 . Ordinary persons are allowed only when accompanied by electrically skilled or instructed persons. The Metal Clad Switchear is fed by two 34KV lines and a tie breaker . Switchgear is a generic term and includes the entire range of switching devices and their combination with associated control, measuring, protecting and regulating equipment. Additionally, the pressure distribution on the walls can be shown as a contour plotting at a certain point in time (Figure 9). Probability calculations on reliability facilitate quantification of the reliability of supply in distribution networks. kindly forward single information as well. -5℃ 24h.average <95% 24h. These network concepts can provide an economical alternative when the construction of an additional transformer substation is to be avoided, or initially implemented with one transformer only. Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! They switch large consumers, mostly in industrial plants, or cable rings which feed switchgear at the secondary distribution level. Accessibility of switches and terminals is categorized according to Table 2 below: Figure 6 (below) shows some examples for the different categories of service continuity: The following aspects play a part when choosing a single or double busbar: A single busbar is sufficient for most supply tasks, even if this supply task consists of two incoming feeders. I sholud be grateful if you could e-mail me a copy of this article in pdf format, i need switch gear training from your company, Is there any standard for busduct trunking. I AM A GHANAIAN AND WOULD LIKE TO KNOW IF YOU OFFER TRAINING PROGRAM FOR MV AND LV PANELS. Examples of reliability characteristics include interruption frequency (stated as 1/a), i.e. Ith=(kA rms 1 s or 3s) (example 25kA rms 1s) This corresponds to a short-circuit in the immediate vicinity of the downstream terminals of the switching device (see fig.1). The terminal voltage per cell varies with the battery's chemical composition. Corridors and access ways must be sufficiently dimensioned for work, operation and transportation of components and must have a. Corridor width must not be obstructed by equipment protruding into the corridor, such as permanently installed drives or switchgear trucks in disconnected position. components; this knowledge leads the design engineer to consult numerous documents and technical catalogues. Load (feeder circuit), power to be distributed (busbar), Bus sectionalizer/ busbar coupler, longitudinal (BCL), Switch-over (BCL) using switch or circuit-breaker, Busbar coupler, transversal (BCT) (double busbar), Grid protection, response times, selectivity criteria, Reserves /service continuity, switch-over times, Interlockings, switching fault protection, Grid protection, selectivity requirements, Numerical ratio of switch panels to circuit-breaker panels, Expandability, electrical / mechanical reserves, Room climate: temperature cycling, humidity, pollution, salt, aggressive gases, Place of installation (spatial requirements), Servicing and maintenance (service life of components), Shock-hazard protection during work in progres, Equipment for control, interlocking, and switching fault protection, Equipment for metering, counting, measured-value transducers, Equipment for monitoring and communication, Damping resistor (for voltage transformer), Grid operation, integration into (industrial) processes and operational procedures, Smaller transportation size and consequently easier shipping, Increased reliability of operation due to hermetically sealed primary switchgear section (adverse impact such as from contamination, small animals, contact, condensation are excluded due to the encapsulation), Maintenance-free primary section (no lubrication and readjustment necessary), Better eco balance than air-insulated switchgear referred to the entire system life cycle, The gas-insulated switchgear is safe to touch thanks to its, HV HRC fuses and cable terminations are only accessible if branch circuits are earthed, Operation is only possible if the enclosure is fully sealed (and any doors closed). The classical approach and the method defined by ANSI/IEEE are two such industry-accepted methods for calculating short circuits. Medium voltage switchgear is used in transformer substations and switching substations, and in secondary unit substations and customer substations (in public utility networks only). Design calculations may be made either manually or by SPU-approved computer programs. The advantages of gas-insulated switchgear are: Lower space requirements (up to approx. Also the total load on the MetalClad Switchgear is 9375 KVA at 34.5KV or 157A what is the multiplier for the Main and Tie breaker is it 125%? its all great stuff keep up the good work. 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