Siemens 38-3AH3 38 kV Primary disconnects, Phase barriers, Stored-energy operating mechanism

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Vacuum interrupter/ operator

Figure 10: Upper and lower primary disconnects (outer-phase barrier removed)

Primary disconnects

Figure 10: Upper and lower primary disconnects (outer-phase barrier removed) is a side view of the circuit breaker with the outer-insulating phase barrier removed to show details of the primary disconnects. Each circuit breaker has three upper- and three lower-primary disconnects. Upper- primary disconnects are connected to the stationary contacts of the vacuum interrupters, and the lower-primary disconnects are connected to the movable contacts. Each disconnect arm has a set of multiple spring-loaded fingers that mate with bus bars in the metal-clad switchgear. The number of fingers in the disconnect assembly varies with the continuous and/ or interrupting rating of the circuit breaker.

There are three insulating push rods. Each push rod connects the movable contact of one of the vacuum interrupters to the jack shaft driven by the closing and tripping mechanism. Flexible connectors provide secure electrical connections between the movable contacts of each vacuum interrupter and its bottom-primary disconnect.

Phase barriers

Figure 11: Type 38-3AH3 vacuum circuit breaker with inter-phase and outer-phase barriers installed on page 17 is a rear view of a type 38-3AH3 vacuum circuit breaker that shows the outer- (phase-to-ground) and interphase-insulating barriers. These glass-polyester insulating barriers are attached to the circuit-breaker frame and provide suitable electrical insulation between the vacuum-interrupter primary circuits and the housing.

Stored-energy operating mechanism

The stored-energy operating mechanism of the type 38-3AH3 vacuum circuit breaker is an integrated arrangement of springs, solenoids and mechanical devices designed to provide a number of critical functions. The energy necessary to close and open (trip) the contacts of the vacuum interrupters is stored in powerful tripping and closing springs. The closing springs are normally charged automatically, but there are provisions for manual charging. The operating mechanism that controls charging, closing and tripping functions is fully trip-free. Trip-free requires that the tripping function prevail over the closing function as specified in ANSI/IEEE

C37.04-1999, clause 6.9. The operation of the stored-energy mechanism will be discussed later in this section.

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Contents Answers for energy Qualified person Table of contents Introduction Signal words Hazardous ProceduresIntroduction Field service operation and warranty issues IntroductionReceiving, handling and storage Introduction Receiving procedureShipping damage claims Handling procedure Receiving, handling and storageStorage procedure Indoor storageOutdoor storage Space heatingInspections, checks and tests without control power Installation checks and functional testsDe-energizing control power in switchgear Installation checks and functional tests Racking crank engagement procedure Type 38-3AH3 vacuum circuit breaker rackingPhysical inspections Manual-spring charging checkFinal mechanical inspections without control power Split-plug jumper connected to circuit breakerVacuum interrupter/ operator Vacuum interrupter/ operator Vacuum interruptersPrimary disconnects Phase barriersStored-energy operating mechanism Interrupter/operator module ConstructionCurrent-path assembly Switching operationCircuit-breaker pole Vacuum interrupterType 38-3AH3 vacuum circuit breaker pole section Stored-energy operating mechanism Auxiliary switch Mode of operationOperating mechanism Indirect releases tripping coilsClosing Use of manual-spring operation crankTrip-free functionality OpeningRapid auto-reclosing Manual operation62.2 62.5.2 50.3.1 53.0 Pawl roller 62.5.2 Close-latch pawl Vacuum interrupter/ operator Discharged Closing Standard Indirect releases dual-trip or Undervoltage optionalSecondary shunt release optional 54.2Position a locked Shock absorber Capacitor-trip deviceSecondary disconnect Mechanism-operated cell MOC switch optional Truck-operated cell TOC switchShutter-operating linkage Secondary disconnect Shutters Trip-free interlock Rating interlockCircuit-breaker frame Ground disconnectRacking mechanism Vehicle function and operational interlocksAlignment Interlocks Circuit breaker racking-interlocksRacking interlocks Closed circuit breaker interlock Automatic closing-spring energy release Trip-free interlock position mechanical interlock Maintenance Introduction and maintenance intervalsMaintenance Recommended hand toolsRecommended maintenance and lubrication Inspection items and testsChecks of the primary power path Removal from switchgearCleanliness check Maintenance and lubrication Circuit NumberInspection of primary disconnects Checks of the stored-energy operator mechanismTypical for all three-phases Fastener check Manual-spring charging and contact- erosion checksWiring and terminals check Automatic spring-charging check control power requiredElectrical-control checks Secondary-disconnect checkTypical vacuum interrupter contact curve Spring-charging motor checks Vacuum-interrupter mechanical checkHigh-potential tests Vacuum-integrity check using dielectric testHigh-potential test voltages Field-test voltage Voltage Frequency withstandInspection and cleaning of circuit- breaker insulation Continuous ContactRating a Functional testsReplacement at overhaul OverhaulCircuit-breaker overhaul Circuit breaker Number TypeVacuum interrupter replacement OverhaulSetting Vacuum interrupter replacement illustration Overhaul Checking the contact stroke Open the circuit breaker Hydraulic shock absorberMaintenance and troubleshooting Sub-assembly Inspect forMaintenance and troubleshooting Problem Symptoms Possible causes and remediesClosed Appendix Appendix Permissible tripping delay Y Maximum design voltageValues Voltage Voltage range factor K3 Insulation Withstand Voltage levels Lightning-impulse BILRated Maximum design voltage Levels Voltage levels Lightning-impulse BILRated Continuous4 Short-circuit at rated maximum design voltage I5, 6Remarks Appendix

38-3AH3 38 kV specifications

The Siemens 38-3AH3 is a high-voltage circuit breaker designed for medium voltage applications, particularly in substations and industrial environments. This device operates at a voltage level of 38 kV, showcasing Siemens' commitment to innovation and reliability in electrical engineering.

One of the main features of the Siemens 38-3AH3 is its advanced interruption technology, which employs the proven hybrid design combining both gas-insulated and air-insulated technologies. This hybrid approach not only enhances the breaker's performance and reliability but also minimizes its footprint, making it an ideal choice for space-constrained environments.

The Siemens 38-3AH3 uses vacuum interruption technology, allowing for efficient switching with minimal wear and tear. The vacuum interrupters are highly reliable and provide excellent performance under various operating conditions. This technology ensures that the circuit breaker can handle short circuits and overloads effectively, thus protecting the entire electrical system.

Additionally, the Siemens 38-3AH3 incorporates intelligent monitoring systems. These digital technologies provide real-time data on breaker status, operational performance, and maintenance needs. This predictive maintenance capability helps operators to identify potential issues before they develop into significant problems, ultimately leading to reduced downtime and maintenance costs.

Another notable characteristic of the Siemens 38-3AH3 is its high insulation strength. Thanks to its robust design and development, this circuit breaker can withstand adverse environmental conditions, making it suitable for use in diverse geographical locations and climates. Its components are designed to resist contamination and corrosion, ensuring long-term reliability.

The Siemens 38-3AH3 also offers enhanced safety features. It includes protective relays and automatic fault detection systems that isolate faults quickly, preventing damage to downstream equipment. Furthermore, the design allows for easy maintenance, with components that are accessible without the need for extensive disassembly.

In summary, the Siemens 38-3AH3 38 kV circuit breaker is a leading solution in high-voltage protection and control, characterized by its advanced interruption technology, integrated monitoring systems, high insulation strength, and user-friendly maintenance features. Its innovative design and engineering make it a trusted choice for utilities and industrial facilities aiming to enhance the reliability and safety of their electrical systems.
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