Transcript
S&C Circuit-Switchers — Mark VI Outdoor Transmission (69 kV through 138 kV)
The Reliable Performance You Expect from S&C Circuit-Switchers . . . With Advanced Interrupting Capabilities For over 20 years, S&C’s Mark V CircuitSwitcher has set the standard for reliable, economical switching and protection of substation transformers and capacitor banks. Now there’s a new Circuit-Switcher that provides the same dependable performance you’ve come to expect from S&C . . . but with added features and benefits meeting today’s system and operational requirements, including a higher-than-ever 31.5-kA fault-interrupting rating and 3-cycle interrupting time. With the addition of pre-insertion inductors—the time-proven method of reducing inrush current and transient overvoltages—Mark VI Circuit-Switcher is tailor-made for capacitor-bank switching and protection. Its enhanced interrupting performance and reliable, repeatable operation is ideal for these applications, eliminating the timing and adjustment problems associated with controlled-closing devices.
69-kV Mark VI Circuit-Switcher . . . add pre-insertion inductors for superior transient control (inset)
Some of Mark VI Circuit-Switcher’s many benefits include: • Three-phase tripping by electrically linked interrupters—Provides tripping simultaneity of less than ¹⁄₄ cycle. • Installation flexibility—Mark VI Circuit-Switcher can be custom-tailored to fit most structures, phase spacings, or bus heights. Its compact, lightweight design reduces expensive real-estate requirements and foundation costs. S&C Mounting Pedestals are available too. • Integral disconnect—Robust high-speed disconnect provides visible air-gap isolation and eliminates the need for a separate mounting structure and foundation. Supersedes Photo Sheet 712-700 dated 8-9-04
S&C ELECTRIC COMPANY
c2005
• Simple installation procedure—Integral disconnect is shipped fully assembled. Lightweight interrupters attach easily to Circuit-Switcher base. • Hermetically sealed interrupters—Eliminate the hassle of field-filling with SF6 gas, while providing 31.5-kA fault-interrupting performance. Interrupters provide full dielectric ratings when open. • Unequalled capacitor switching and protection— Optional pre-insertion inductors dramatically reduce inrush current and tame damaging overvoltages that can shut down sensitive adjustable-speed drives. • Reliable—Mark VI has been tested to 5000 mechanical operations.
PHOTO SHEET
712-700 Page 1 of 4 March 21, 2005
S&C Circuit-Switchers — Mark VI Outdoor Transmission (69 kV through 138 kV) Construction Mark VI Circuit-Switcher combines the robust verticalbreak disconnect of Mark V Circuit-Switchers with new interrupting technology, for higher interrupting ratings and enhanced installation flexibility. The circuit-makingand-isolating disconnect, powered by the rugged S&C Mark VI Type CS-1A Switch Operator, is capable of opening and closing without hesitation under ³⁄₄-inch ice formation. The operator’s heavy-duty motor enables highspeed, high-torque closing of the disconnect—providing close interphase simultaneity, long life of closing contacts, and avoidance of excessive switching transients due to prolonged or unstable prestrike arcing. The SF6-gas-filled, single-gap, puffer-type interrupters are enhanced. They’re factory-filled, tested, then permanently sealed. Field-filling is never needed, eliminating the risk of contaminating the interrupting medium and saving installation time. Interrupters use lightweight,
shatterproof, composite-polymer silicone insulation— providing outstanding performance, even in contaminated environments. Each interrupter has its own permanently sealed storedenergy trip mechanism and a charging motor. After the Circuit-Switcher has been called upon to trip and the disconnect has opened to establish a visible air gap, the charging motors close and charge the interrupters. Each interrupter includes a built-in limit switch that prevents overcharging of the trip mechanism, and ensures that the interrupter is either fully open or fully closed. Local indication of interrupter state—“closed” or “open”—is provided at the base of each interrupter. Each interrupter also includes a temperature-compensated SF6 gas-pressure gauge, with two gas-indicator levels. A remote gas-density indicator, providing indication of the two alarms, is optionally available.
Interrupter Disconnect blade assembly
Available with optional quick-connect control cable for easy installation.
Insulators
Trip mechanism (sealed inside interrupter)
Base (disconnect pre-assembled on base)
Charging motor (closes interrupter contacts)
Single-phase view
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PHOTO SHEET S&C ELECTRIC COMPANY
How It Operates The circuit is opened inside the electrically tripped interrupters, and closed via the vertical-break, power-operated disconnect. Proper sequence of operation is ensured.
Mark VI CS-1A Switch Operator
Mark VI Circuit-Switcher is compatible with a wide variety of user-furnished relays and control devices, for comprehensive protection. Circuit-Switchers feature instantaneous trip-free performance: Should the CircuitSwitcher be closed into a fault sensed by user-furnished relaying, the interrupters will be tripped immediately.
Opening the circuit: 1. Interrupters open in response to user-furnished trip signal or when local “Trip” push button is pressed. 2. Disconnect opens, creating visible air gap. 3. Motor operators close the interrupters and charge the springs in the trip mechanisms.
Closing the circuit: Disconnect closes in response to user-furnished close signal or when local “Close” push button is pressed.
Pre-Insertion Inductors Mark VI Circuit-Switchers are available with optional preinsertion inductors for use in shunt capacitor-bank switching and protection applications. Pre-insertion inductors are exceptionally effective for limiting: • Inrush current and overvoltage at the capacitor bank bus—reducing the incidence of spurious signals, insulation puncture, and component damage. • Phase-to-phase switching-surge overvoltages at remote transformers—reducing the chance of transformer failure due to voltage stress across the transformer windings.
• Overvoltages on long, open-ended lines—preventing nuisance operation of surge arresters. • Transient overvoltages on users’ utilization-voltage bus—voltage magnification of capacitor-switching transients can cause nuisance tripping of adjustablespeed drives and other sensitive electronic devices. S&C Pre-Insertion Inductors are comprised of two or more close-coupled layers of stainless-steel or aluminum conductor wound with a resin-impregnated filament-fiberglass roving, to form a hollow glass-reinforced tube. A counter-wound stainless-steel damping winding is added to limit the voltage across the Circuit-Switcher interrupter during opening. A layer of roving separates the layers of conductor, and other layers of roving are added for mechanical strength and stability. The inductor is weather-sealed with silicone-alkyd paint. Circuit-Switchers with pre-insertion inductors are not capable of faultclosing duty.
PHOTO SHEET S&C ELECTRIC COMPANY
712-700 Page 3 of 4 March 21, 2005
S&C Circuit-Switchers — Mark VI Outdoor Transmission (69 kV through 138 kV)
MARK VI CIRCUIT-SWITCHERS—50/60-HZ RATINGS1 kV Nom.
Max
Amperes, RMS BIL
Cont.
4-Hour
Peak Withstand
1-Sec.
Fault-Closing, Duty-Cycle, Two-Time2
69
72.5
350
420
630
81 900
31 500
30 000
115
123
550
420
630
81 900
31 500
30 000
138
145
650
420
630
81 900
31 500
30 000
1 All Mark VI Circuit-Switchers include a Mark VI Type CS-1A operator to power the integral disconnect.
2 Mark VI Circuit-Switchers with pre-insertion inductors are not suitable for fault-closing duty.
INTERRUPTING RATINGS Application Class
Maximum Amperes, Interrupting, RMS Symmetrical
Qualifications
Load Dropping1
Duty-Cycle Fault Interrupting23 Transformer Switching and Protection Secondary Faults4
—
630
3-Time
31 500
5-Time
18 900
10-Time
9450
30-Time
3150
69 kV
4200
115 kV and 138 kV
2600
Internal faults—see both primary and secondary faults, above
Fault Interrupting23
1 Mark VI Circuit-Switchers can close, carry, and interrupt the magnetizing current of the protected transformer.
2 Rating is based on transient-recovery voltage parameters defined in the following tables of IEC Standard 60056, Edition 4.0: 1987: For Circuit-Switchers rated 69 kV: Tables IIa, XVa, and XVIa. For Circuit-Switchers rated 115 kV and 138 kV: Tables IIc, XVc, XVIc, and XVII.
3 The interrupting ratings shown are applicable for the following duty cycles: O or CO.
4 Mark VI Circuit-Switchers are suitable for transformer-primary applications where the inherent secondary-fault current—the secondary-side fault current as reflected on the primary side of the transformer, assuming an infinite (zero-impedence) source—does not exceed this value for a
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420
Ungrounded capacitor banks applied through 138 kV
420
—
31 500
fault external to the transformer. The inherent secondary-fault current may be calculated as follows: 57.8P I = ---------------(%Z)E where I Inherent secondary-fault current, amperes P Transformer self-cooled three-phase rating, kVA E Primary-side phase-to-phase voltage, kV %Z Percent transformer primary-to-secondary impedance, referred to transformer self-cooled three-phase kVA rating
Mark VI Circuit-Switchers cannot be applied on systems with shortcircuit currents in excess of this value.
PHOTO SHEET S&C ELECTRIC COMPANY
Printed in U.S.A.
Capacitor-Bank Switching and Protection
Bank Current Switching
Grounded capacitor banks applied on solidly grounded systems only, through 138 kV
