Controlled Switching - Buyers and Application Guide for SwitchSync
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Controlled Switching Buyer's and Application Guide

Application, connection and choice: Capacitor banks and Harmonic filters 14 Impact of substation configuration 40 Circuit breakers with mechanically staggerd poles 43 Technical Data: Technical data Shipping data Quality, testing and commissioning Inquiry data 2 Content | Buyer's Guide, Application Guide

Controlled Switching with Switchsync™ ABB has extensive service experience with controlled switching, and the first generation of Switchsync™ controllers was launched in 1986. Controlled switching is used for elimination of harmful electrical transients upon planned switching of mainly capacitor banks, shunt reactors and power transformers. The method is also gaining acceptance for reenergizing of EHV transmission lines, and replacing traditional pre-insertion resistors. Since 1986, thousands of Switchsync™ controllers have been delivered all over the world. ABB is at the forefront of...

Applications Applications The following applications apply to controlled switching: Shunt capacitor banks: Basic aim is to control closing to minimize the energizing transients (voltage transients as well as inrush currents). To improve interrupting performance, controlled opening can also be utilized. Shunt reactors: Basic aim is to control de-energizing to ensure reignition-free behavior. In addition, controlled closing also serves as a useful method for minimizing inrush currents. No-load transformers: The purpose of controlled no-load transformer switching is to minimize the inrush...

The strategy for controlled opening is to select arcing times long enough to avoid reignitions at de-energizing. The strategy may vary depending on the size of the shunt reactor. The strategy for controlled closing is to energize at instants resulting in flux symmetry (current symmetry) thereby minimizing the risk for nuisance tripping and rotor vibrations in nearby generators due to zero sequence current. An alternative strategy for controlled energizing is to energize the reactor such that the voltage fronts will be minimized. This will require energizing close to voltage zero and there...

Switchsync™ controllers Type of controllers The following five types of controllers are in the product program: E113 E213 F236 L183 T183 The letters indicate basic function: E = standard model for switching at fixed target(s) F = fully equipped model for switching at fixed targets L = special model for switching of uncompensated transmission lines T = special model for switching of power transformers −− First digit in name indicates the number of input commands. − − Second digit indicates the number of adaptive channels or important signals for the function. − − Third digit indicates the...

For controllers L183 and T183 the switching instants will vary. The targets will vary depending on the previous interrupting conditions and target for the next making operation is determined by load side voltage measurements. Phase shifts All targets are expressed with respect to a reference time instant, that for all controllers is a busbar voltage zero or, in special applications, a current zero. For controlled closing, the target(s) are defined as a certain phase shift(s) with respect to the reference. For controlled opening, the ultimate targets are certain contact separation instants...

Circuit breaker characteristics Single-pole or three-pole operation When a single-pole operated circuit breaker is controlled, a separate output command is given to each pole. Three-pole operated circuit breakers can be arranged with mechanical staggering, making them suitable for controlled switching. In these cases, there will be a built-in mechanical spread (phase shift) between the poles that is appropriate for optimized switching of the load at the specified frequency. The mechanical spread is arranged to reach proper switching conditions with minimum staggering (which for grounded...

Control circuit arrangements Fault clearance Since a controlled opening operation will cause an extended clearing time (input check duration, time for finding final reference point and additional waiting time) it is important to arrange all fault tripping commands to by-pass the controller. Substations Different substation arrangements may call for special solutions for overall total functionality. Double circuit breaker schemes and “one-and-a half” circuit breaker schemes (breaker-and-a-half) may require special arrangements for attaining proper function of adaptation control. Trip Circuit...

Controlled switching with Switchsync™ Introduction Suppression of switching transients There are several important circuit breaker applications where random closing or opening instants may lead to severe voltage and current switching transients. These transients occur in the main circuits, but may also induce transients in control and auxiliary circuits, as well as in adjacent low voltage systems. The switching transients are associated with a variety of dielectric and mechanical stresses on the high-voltage equipment, and may cause gradual or immediate damage to the system or the...

If controlled opening is applied it is important that all protection trip commands, in the event of fault interruptions, are by-passing the controller. In secure mode operation the ”controlled way” is typically extended by about 120 ms at 50 Hz compared to a direct trip command. When the capacitor bank is to be energized, an input command is given to the Switchsync™ controller. Following the command, the controller will determine a reference time instant, related to the phase angle of the busbar voltage. When this has been done, and after an internally created waiting time, the controller...

Controlled switching with Switchsync™ Introduction It should be noted that circuit breakers of other design, e.g. using other types of mechanisms, may show larger variations in operating times, statistically from operation to operation, and also as a result of variations in ambient temperature etc. It may therefore be less beneficial to use such circuit breakers for controlled switching applications. The dielectric properties between the contacts, upon making or breaking operations, may also be less suitable. In addition, the controlled circuit breaker itself will experience reduced...