For Substation Capacitor Banks and Shunt Reactors Specifications Conditions of Sale STANDARD: Seller s standard conditions of sale set forth in Price Sheet 150 apply, except as modified by the SPE CIAL WARRANTY PROVISIONS, and WARRANTY QUAL IFICATIONS sections in this specification bulletin. SPECIAL TO THIS PRODUCT: INCLUSIONS: The S&C BankGuard Plus Control protects substation shunt capacitor banks from overvoltage stress and provides turn-to-turn winding fault protection for shunt reactors. The BankGuard Plus has the sensitivity to detect and alarm on the loss of individual capacitor units or developing winding faults. With the capability to detect and alarm upon the loss of the first failed capacitor unit in a bank, the BankGuard Plus offers users a major advantage: The failed unit can be replaced at a convenient, planned time... not on an urgent basis, after subsequent capacitor units have failed and the bank has been locked out. An adjustable time delay is utilized to avoid false alarms due to transient dis turbances. Nuisance alarms and lockouts due to the induction of high voltages during routine bank de-energi zation are also eliminated. The BankGuard Plus can detect and compensate for system voltage and capacitor-bank or reactor unbalance resulting from manufacturing-tolerance variations among the individual capacitor units and reactor phase windings.f In large-size capacitor banks, such unbalance voltages can introduce significant errors in, or even overpower, the voltage signal created by the loss of individual capacitor units. The BankGuard Plus includes filtering to attenuate spurious transients and harmonics. The BankGuard Plus further includes gross-overvolt age logic which bypasses the lockout-level and timing-control logic to achieve fast capacitor-bank or reactor iso lation in the event of a flashover of a series group in the bank or flashover of a significant portion of a phase wind ing. The BankGuard Plus is suitable for standard 19-inch relay rack mounting. An optional bezel is available for flush mounting in a switchboard or control console. The BankGuard Plus is a direct replacement for S&C Automatic Control Devices Types UP, GP, and UPR. Terminal strip connections are identical with those of the Type UP and all connections for Types GP and UPR are accommodated. Protection of Ungrounded, Wye-Connected Shunt Capacitor Banks, Including Double-Wye Banksl In these applications, the BankGuard Plus monitors the voltage between the neutral (common) connection of the capacitor bank and ground with a 15-volt-ampere S&C Potential Device. As successive individual capacitor units in a series group of the bank are isolated by their respec tive fuses, the surviving capacitor units in the group are protected against cascading voltage overstress by the BankGuard Plus, which isolates and locks out the entire bank when a predetermined neutral-to-ground voltage Protection of Grounded, Wye-Connected Shunt Capacitor Banks Consisting of Two or More Series Groups per Phase In these applications, the BankGuard Plus monitors, for each phase of the capacitor bank, the voltage between an intermediate tap point and ground with a 30-volt-ampere S&C Potential Device. As successive individual capacitor units in a series group of the bank are isolated by their respective fuses, the surviving capacitor units in the group are protected against cascading voltage overstress by the BankGuard Plus, which isolates and locks out the entire bank when a predetermined tap point-to-ground voltage Protection of Ungrounded, Wye-Connected Shunt Reactorsl In these applications, the BankGuard Plus monitors the voltage between the neutral (common) connection of the reactor and ground with a 15-volt-ampere S&C Potential Device. If a turn-to-turn fault develops in a phase winding, the BankGuard Plus isolates and locks out the entire reactor when a predetermined neutral-to-ground voltage f For proper unbalance, the system-derived voltages monitored by the BankGuard Plus must be obtained by means of 30-volt-ampere S&C Potential Devices or voltage transformers connected to the segment of station bus to which the capacitor bank or reactor is tapped. Connecting circuits from the potential devices or voltage transformers to the BankGuard Plus must be free of variable loads, variable voltage drops, and ground loops so that the voltages monitored accurately represent the magnitude and phase angle of the bus voltages. l For applications where the source is a delta-connected tertiary transformer winding, a grounded-wye broken-delta voltage-transformer bank with shunt resistor referred to as a high-impedance grounding transformer (normally required for ground-fault detection) is required to maintain the stability of phase-to-ground voltage relationships for all but fault conditions. Otherwise spurious signal voltages could appear at the neutral of, and result in isolation of, the capacitor bank or reactor. The BankGuard Plus includes an unbalance that detects and compensates for up to 10% error voltage appearing between the neutral and ground. October 29, 2012 S&C Electric Company Specification Bulletin 1011-31
Conditions of Sale Continued SPECIFICATION NOTES: S&C BankGuard Plus Controls have been tested to verify their capability to withstand, without misoperation or damage, surge-voltage tests as follows: 1. The ANSI Surge Withstand Capability Test (ANSI Standard C37.90a, 1974). The specified surges are applied at all control device terminals. 2. A 5-kV, 3.75-joule capacitive-discharge test with surge applied at all control device terminals. This additional test represents a surge level well in excess of those normally encountered in control wiring in utility environments. To prevent damage to the control device in the event that surges which exceed factory-tested levels are encountered, S&C s control-circuit fusing recommenda tions must be followed. The required fuse blocks and fuses are furnished with the control devices. If frequent surges in excess of factory-tested levels are anticipated, S&C should be advised as to the severity of the surges so that special recommendations can be made. For all grounded-wye capacitor-bank installations the following steps must be taken to ensure that the control device is not subjected to surges in excess of the level defined in ANSI Standard C37.90a: 1. Adequate shielding must be provided for control-cir cuit wiring. 2. For installations involving two or more grounded-wye capacitor banks in the same station, their neutrals must be interconnected and grounded at a single point only. Additionally, it is recommended (although not required) that the capacitor-bank switching devices be equipped with pre-insertion impedances for reduction of inrush current and transient voltage disturbances associated with capacitor-switching applications. EXCLUSIONS: BankGuard Plus Controls do not include voltage-monitoring devices. Refer to Specification Bulletin 581-31 for information on S&C Potential Devices. SPECIFICATION DEVIATIONS: Refer to Options table on page 4. SPECIAL WARRANTY PROVISIONS: The standard warranty contained in seller s standard conditions of sale, as set forth in Price Sheet 150, applies to BankGuard Plus Controls, except that the first paragraph of said warranty is replaced by the following: (1) General: Seller warrants to immediate purchaser or end user for a period of 10 years from the date of shipment that the equipment delivered will be of the kind and quality specified in the contract description and will be free of defects of workmanship and material. Should any failure to conform to this warranty appear under proper and normal use within ten years after the date of shipment the seller agrees, upon prompt notification thereof and confirmation that the equipment has been stored, installed, operated, inspected, and maintained in accordance with recommendations of the seller and standard industry practice, to correct the nonconformity either by repairing any damaged or defective parts of the equipment or (at seller s option) by shipment of necessary replacement parts. The seller s warranty does not apply to any equipment that has been disassembled, repaired, or altered by anyone other than the seller. This limited warranty is granted only to the immediate purchaser or, if the equipment is purchased by a third party for installation in third-party equipment, the end user of the equipment. The seller s duty to perform under any warranty may be delayed, at the seller s sole option, until the seller has been paid in full for all goods purchased by the imme diate purchaser. No such delay shall extend the war ranty period. Replacement parts provided by seller or repairs performed by seller under the warranty for the original equipment will be covered by the above special warranty provision for its duration. Replacement parts purchased separately will be covered by the above special warranty provision. WARRANTY QUALIFICATIONS: Warranty of Bank Guard Plus Controls is contingent upon the installation, configuration, and use of the control or software in accordance with S&C s applicable instruction sheets. This warranty does not apply to major components not of S&C manufacture, such as batteries, communication devices, and remote terminal units. However, S&C will assign to immediate purchaser or end user all manufacturers warranties that apply to such major components. END USER LICENSE AGREEMENT: End user is granted a nontransferable, non-sublicensable, nonexclusive license to use the IntelliLink Remote Setup Software and/or other Software furnished with S&C BankGuard Plus Controls only upon acceptance of all the terms and conditions of the seller s end user license agreement set forth in Price Sheet 155. 2 S&C Specification Bulletin 1011-31
How to Order 1. Control a. Select the catalog number of the desired control from the table on page 4. b. Add Suffix -B to the catalog number if the optional bezel is desired. See the Options table on page 4. c. For calibration purposes, include information on the neutral-, tap-, and/or system-voltage devices used, i.e., catalog number of S&C Potential Device(s), or primary voltage rating and turns ratio of voltage transformer(s) Plus nominal voltage of voltage-transformer secondary circuit.m 2. Example For an S&C BankGuard Plus Control for application on an ungrounded capacitor bank connected to a sys tem rated 138 kv nominal, specify: Catalog Number 238062, for use with one S&C 15-volt-ampere S&C Potential Device, Catalog Number 81576R1, and,, three 30-volt-ampere S&C Potential Devices, Catalog Number 81349R6-T (or three voltage transformers with a primary rating of 80,500 volts, turns ratio of 1200:1, and secondary cir cuit rated 67.08 volts), for application on a system rated 138 kv nominal. m If no information on the neutral-, tap-, and/or system-voltage devices is specified, the device will be shipped marked for field calibra tion. S&C Specification Bulletin 1011-31 3
Bankguard Plus Controls Diagram Control Application1 Switch Operator Potential Device BankGuard Plus Control Control- Source Voltage Catalog Number Page Reference for Dimensional Information Net Wt., Lbs. (Kg.) For protection of ungrounded, wyeconnected and double-wye-connected shunt capacitor banks2 For protection of grounded, wyeconnected shunt capacitor banks 48 to 250 Vdc or 120 to 240 Vac, 50 or 60 Hz 238062 5 11 (4.95) For protection of ungrounded, wyeconnected shunt reactors2 1 For installations in the vicinity of 345-kV or 500-kV circuits, refer to the nearest S&C Sales Office. 2 For applications where the source is a delta-connected tertiary transformer winding, a grounded-wye broken-delta voltage-transformer bank with shunt resistor referred to as a high-impedance grounding transformer (normally required for ground-fault detection) is required to maintain the stability of phase-to-ground voltage relationships for all but fault conditions. Otherwise spurious signal voltages could appear at the neutral of, and result in isolation of, the capacitor bank or reactor. S&C BankGuard Plus Controls include an unbalance that detects and compensates for up to 10% error voltage appearing between the neutral and ground. n S&C Potential Device rated 15 volt-amperes having a system voltage rating as follows: Nominal Source Voltage, kv below 23 23 34.5 46 69 115 138 161 230 S&C Potential Device System Voltage Rating, kv, Nom. 23 23 23 23 34.5 69 69 138 138 The 15-VA Potential Device is recommended. If a 30-VA Potential Device is used for neutral-to-ground it must either be equipped with factory-adjusted calibration device, Catalog Number Suffix -T, or a locally installed 480-ohm, 50-watt resistor may be used to terminate the secondary output of the 30-VA Potential Device. l S&C Potential Device rated 30 volt-amperes equipped with factoryadjusted calibration device, Catalog Number Suffix -T. The minimum system voltage rating of the potential device is derived by calculating the voltage appearing between the intermediate tap points and ground and multiplying this value by 3. Since S&C Potential Devices are not of instrument-class accuracy, their performance in intermediate-tap-point voltage-monitoring applications on very-large-sized grounded, wye-connected shunt capacitor banks may not be entirely satisfactory, especially if it is desired to obtain an alarm signal upon the loss of a single capacitor unit. Specifically, this alarm signal setting on banks consisting of more than 150 capacitor units or more than 5 series groups per phase (often the case where system voltage is higher than 138 kv) may possibly lead to nuisance alarms under severe rainfall conditions. In cases where such false operations are of especial concern, higher-accuracy devices such as voltage transformers or capacitor-coupled voltage transformers are recommended. The minimum system voltage rating of these devices is derived by calculating the voltage appearing between the intermediate tap points and ground and multiplying this value by 3. Adequate damping resistance must be connected across each voltage-transformer secondary circuit; viz., a resistance load equal to at least 2% of the transformer thermal rating. w S&C Potential Device rated 30 volt-amperes (or voltage transformer) having a system voltage rating equal to the voltage of the system to which the capacitor bank or reactor is connected. If capacitor-unit or reactor phase-winding manufacturing tolerance variations are of specific con cern, a single potential device or voltage transformer is required. If sys tem voltage unbalance is also of concern in ungrounded capacitor bank or reactor applications, three potential devices or voltage transformers are required. Options Item Suffix to be Added to Control Catalog Number Mounting Bezel for Flush Mounting of BankGuard Plus Control, 220 W 80 H Z\v0 D -B 4 S&C Specification Bulletin 1011-31
BankGuard Plus Dimensions in inches (mm) 17.13 (435) 5.25 (133.4) 14.68 (372.9) 13.97 (354.8) 1.50 (38.1) 19.00 (482.6) 18.13 (460.5) 5.25 (133.4) 2.25 (57.2) UNBALANCE COMPENSATION LOCKOUT LEVEL 4.97 (126.2) PUSH TO SET PUSH TO READ PUSH TO RESET S&C Specification Bulletin 1011-31 5