ESTAsym CPR www.vishay.com Vishay ESTA Unbalance Protection Relay FEATURES • Separately adjustable thresholds for alarm and trip • Separately adjustable delay time for alarm and trip • Compensation of the natural unbalance • Adjustable transformer ratio (voltage / current) • With low pass filter • One free programmable output relay APPLICATIONS • Monitoring unbalance currents of capacitor banks - Double-star connection - Bridge connection • Monitoring unbalance voltages of capacitor banks QUICK REFERENCE DATA Description Type Supply voltage Unbalance protection relay for capacitor banks connected in double-star or bridge connection Unbalance protection relay 40 VAC to 250 VAC, 50 Hz to 60 Hz / 40 VDC to 300 VDC Measuring voltage 0.2 V to 20 V, burden 284 k Measuring current 20 mA to 5 A Relay outputs Digital input Interfaces Temperature Humidity Overvoltage class standards Standards AC: max. 1250 VA DC: 30 V / 5 A, 60 V / 1 A, 110 V / 0.5 A, 220 V / 0.3 A Blocking alarm / trip via digital input TTL, rear (optional: RS485, Modbus RTU) Operation: -20 °C to +70 °C Storage: -40 °C to +85 °C 0 % to 95 %, without moisture condensation II, polution degree 3 (IEC 60664-1) IEC 60664-1, IEC 61010-1, IEC 61326 Conformity and listing Terminals Casing front Protection level Weight CE Screw type, maximum 4 mm2 Instrument casing plastic (UL 94 V-0), rear: metal IP50, IP54 by using a gasket; rear: IP20 0.65 kg Note • Complete mounting instructions / manual available at www.vishay.com/doc?13172 Revision: 12-Nov-14 Document Number: 13176 1 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 ESTAsym CPR www.vishay.com Vishay ESTA The operation of high- and medium-voltage capacitors needs to be monitored constantly. Most such capacitors use insulating oil for their dielectrics, and monitoring is required to avoid any combustion of this material in event of failure. This monitoring can be done either by monitoring the unbalance current or unbalance voltage of capacitor groups. However, this voltage/current may change in case of any failure of one capacitor, for instance caused by a flashover inside the wound foils. APPLICATIONS MONITORING UNBALANCING CURRENT Double-Star Connection In a double-star connection, the star points of two capacitor groups are connected together as shown in Fig. 1. In the event of a failure, i.e., element breakdown or group short-circuit, the star point of the respective branch is shifted and causes a current flow between the star points. The intensity of the current is determined by the capacitor construction and the number of capacitors. CPR Fig. 1 - Double-star connection Bridge Connection In a bridge connection, as shown in Fig. 2, the capacitor bank is built up with four bridge branches, with two branches each constituting a series connection. The medium potentials of the branches are connected by a current transformer. The division of the bridge branches preferably should be symmetrical. An unsymmetrical structure would also be possible. However, with an unsymmetrical structure, the pick-up values must be set to the more sensitive branch. CPR Fig. 2 - Bridge connection MONITORING UNBALANCE VOLTAGE To monitor the capacitor bank via the voltage, the voltage of the capacitors of the three phases is connected to three two-pole insulated PTs, which are on the secondary side connected in series. In Fig. 3, the ESTAsym CPR is measuring the voltage at this open delta. L1 L2 L3 CPR 20 mA - 5 A 0.2 V - 20 V Fig. 3 Revision: 12-Nov-14 Document Number: 13176 2 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 ESTAsym CPR www.vishay.com Vishay ESTA OPTIONAL FEATURES Interface RS485, Modbus RTU Programming via USB 2.0 interface FUNCTION The ESTAsym CPR is designed to monitor medium- and high-voltage capacitors. The ESTAsym CPR can be set from the menu to monitor current or voltage. The device can monitor two threshold levels for alarm / trip. All thresholds / readings can be set either as a specific current or voltage value or as a percentage of the maximum value. Once the alarm or trip level is reached, the appropriate relay will operate, after the programmed delay time has elapsed. Both output relays can be programmed to be held in the alarm / trip position until reset by the user. Alternatively they can be set to automatically reset if the fault condition has cleared. A further output relay can be used to operate when the alarm / trip or both alarm and trip have operated. The ESTAsym CPR can record details of the last five alarm and trip operations. An natural unbalance (out of balance or asymmetrical value) can be programmed into the device if required. This natural unbalance is subtracted from the measured value and allows a more exact setting of the thresholds. Measured Value - Natural Unbalance = Value Revision: 12-Nov-14 Comparator Adjusted Threshold Value > Limit Alarm / Trip Delay Time Adjusted Delay Time Alarm / Trip for Alarm / Trip Monitoring Blocked via DI1 and DI2 Switch Output Relay Output Relay 1 Trip Output Relay 2 Alarm Output Relay 3 Progr. Document Number: 13176 3 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 Legal Disclaimer Notice www.vishay.com Vishay Disclaimer ALL PRODUCT, PRODUCT SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE WITHOUT NOTICE TO IMPROVE RELIABILITY, FUNCTION OR DESIGN OR OTHERWISE. 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We confirm that all the products identified as being compliant to IEC 61249-2-21 conform to JEDEC JS709A standards. Revision: 02-Oct-12 1 Document Number: 91000