Power Breakers

The overcurrent protection for AC installations uses three types of electronic release series: PR121/P, PR122/P and PR123/P.
The basic series, PR121/P, offers the whole set of standard protection functions, complete with a user-friendly interface. It allows discrimination of which fault caused the trip by means of the new led indications.
PR122/P and PR123/P releases are of new concept modular architecture. It is now possible to have a complete series of protections, accurate measurements, signalling or dialogue functions, designed and customisable for all application requirements.
The protection system is made up of:

• 3 or 4 new generation current sensors (Rogowsky coil);
• external current sensors (i.e. for external neutral, residual current or source ground return protection);
• a protection unit selected among PR121/P, PR122/P or PR123/P with optional communication module via Modbus or Fieldbus plug network (PR122/P and PR123/P only), as well as via a wireless connection;
• an opening solenoid, which acts directly on the circuit-breaker operating mechanism (supplied with the protection unit).

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PR121/P is the new basic and complete release for the Emax series. The complete range of protection functions together with the wide combination of thresholds and trip times offered make it suitable for protecting a wide range of alternating current installation. In addition to protection functions the unit is provided with multifunction LED indicators. Furthermore, PR121/P allows connection to external devices enhancing its advanced characteristics like remote signalling and monitoring, or remote supervision display.

Protection functions


The PR121 release offers the following protection functions:

• overload (L)
• selective short-circuit (S)
• instantaneous short-circuit (I)
• earth fault (G).

User interface
The user communicates directly with the release in the trip parameter preparation stage by means of the dip switches.
Up to four LEDs (according to the version) are also available for signalling. Communication
By means of the BT030 wireless communication unit, PR121/P can be connected to a pocket PC (PDA) or to a personal computer, extending the range of information available for the user.
PR121/P can also be connected to the optional external PR021/K signalling unit, for the remote signalling of protections alarms and trips, and to HMI030, for the remote user interfacing. Setting the neutral
Protection of the neutral can be set at 50%, 100% or 200% of the phase currents. Test Function
The Test function is carried out by means of the info/Test pushbutton and the PR030/B battery unit (or BT030).
The PR121/P electronic release can be tested by using the SACE PR010/T test and configuration Unit.


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The SACE PR122 release is a sophisticated and flexible protection system based on a state-of-the art microprocessor and DSP technology. Fitted with the optional internal PR120/D-M dialogue unit, PR122/P turns into an intelligent protection, measurement and communication device, based on the Modbus® protocol. By means of the PR120/D-M, PR122/P can also be connected to the ABB EP010 Fieldbus plug adapter, which makes it possible to choose among several different networks, such as Profibus and DeviceNet.
The exhaustive range of settings makes this protection unit ideal for general use in any type of installation, from distribution to the protection of motors, transformers, drives and generators.
Access to information and programming using a keyboard and graphic liquid crystal display is extremely simple and intuitive. The interface is now common to PR122/P and PR123/P in order to give to the user maximum ease of use.
An integrated ammeter and many other additional features are provided over and above the protection functions. These additional functions can be further increased with addition on board of the dialogue, signalling, measurement, and wireless communication units.

Protection functions


Basic protection functions
The PR122/P release offers the following protection functions (according to the version):

• overload (L)
• selective short-circuit (S)
• instantaneous short-circuit (I)
• earth fault (G)
• phase unbalance (U)
• self-protection against overtemperature (OT)
• thermal memory for functions L and S
• zone selectivity for functions S and G
• residual current (Rc) with external toroid
• source ground return with external toroid

Additional protection functions
The PR122/P release with the additional module PR120/V also offers the following protection functions:

• undervoltage (UT)
• overvoltage (OV)
• residual voltage (RV)
• reverse power (RP)
• underfrequency (UF)
• overfrequency (OF)

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The PR123/P protection release completes the range of releases available for the Emax family of circuit-breakers.
It is a high-performance and extraordinarily versatile release, capable of offering a complete set of functions for protection, measurement, signalling, data storage and control of the circuit-breaker, and it represents the benchmark in low voltage protection units for circuit-breakers.
The front interface of the unit, common to PR122/P, is extremely simple thanks to the aid of the liquid crystal graphics display. It can show diagrams, bar graphs, measurements and sine curves for the various electrical values.
PR123 integrates all the features offered by PR122/P plus a series of evolutes functionalities. As well as PR122 it can be integrated with the additional features provided by internal modules and external accessories.

Protection functions


Basic
The PR123 release offers the following protection functions:

• overload (L) ,
• selective short-circuit (S),
• instantaneous short-circuit (I),
• earth fault with adjustable delay (G),
• directional short-circuit with adjustable delay (D),
• phase unbalance (U),
• protection against overtemperature (OT),
• load control (K),
• undervoltage (UV),
• overvoltage (OV),
• residual voltage (RV),
• reverse power (RP),
• underfrequency (UF),
• overfrequency (OF),
• phase sequence (alarm only).

In addition to PR122/P features, the following improvements are available:
Overload protection L
The overload protection L includes the option to adjust the slope of the protection curve
Double selective short-circuit protection S
In addition to the standard S protection, PR123/P makes contemporarily available a second time-constant S protection (excludible) that allows two thresholds to be set independently achieving an accurate selectivity even under highly critical conditions.
Double earth fault protection G
While in PR121/P and PR122/P the user must choose among the implementation of G protection through internal current sensors (calculating the vectorial sum of currents) or external toroid (direct earth fault current measuring), PR123/P offers the exclusive feature of the contemporaneous management of both the configuration, by means of two independent earth fault protections curves. The main application of this characteristic is simultaneous activation of restricted and unrestricted earth fault protection.
Directional short-circuit protection with adjustable delay D
The protection works in a similar way to the fixed-time protection .S., with the added ability to recognize the direction of the phases current during the fault period.
The current direction makes it possible to determine whether the fault is on the supply or load side of the circuit-breaker. Particularly in ring distribution systems, this makes it possible to identify and disconnect the distribution segment where the fault has occurred, whilst keeping the rest of the installation running.
Dual setting of protections
PR123/P can store an alternative set of all the protection parameters. This second set (set B) can replace, when needed, the default set (set A) by means of an external command. The command can be given typically when network configuration is modified, like when a parallel of incoming lines is closed or when an emergency source is present in the system, changing load capability and short-circuit levels.
Zone selectivity function
The zone selectivity function allows the fault area to be insulated by segregating the system very rapidly only at the level closest to the fault, whilst leaving the rest of the installation running.

Additional
The PR123/P release with the additional module PR120/V also offers the following protection functions:

• undervoltage (UT)
• overvoltage (OV)
• residual voltage (RV)
• reverse power (RP)
• underfrequency (UF)
• overfrequency (OF)

Measurement functions
The PR123/P release provides a complete set of measurements:

• Currents: three phases (L1, L2, L3), neutral (Ne) and earth fault
• Voltage: phase-phase, phase-neutral and residual voltage
• Power: active, reactive and apparent
• Power factor
• Frequency and peak factor
• Energy: active, reactive, apparent, counter
• Harmonics calculation: up to the 40th harmonic (waveform and module of the harmonics displayed); up to the 35th for frequency f = 60Hz

Maintenance: number of operations, percentage of contact wear, opening data storage.


TestBus2 is the ABB SACE commissioning and diagnostic software for all Modbus RTU devices.
It can be used during system startup, or to troubleshoot an installed network.
TestBus2 automatically scans the RS-485 bus, detects all connected devices and checks their communication settings. All possible combination of device address, parity and baud rate are checked.


The PR122/P and PR123/P can be enriched with additional internal modules, increasing the capacity of the release and making this unit highly versatile:

PR120/K Electrical signalling contacts module This unit allows the remote signalling of alarms and trips of the circuit breaker. Four independent power relays provided on the PR120/K release enable electrical signalling of the following: timing for protections L, S, G (and UV, OV, RV, RP, D, U, OF, UF where applicable); protections L, S, I, G, OT, (and UV, OV, RV, RP, D, U, OF, UF where applicable) tripped and other events; in addition, by using an external device (PR010/T, BT030, PR120/D-BT), the contacts can be freely configured in association with any possible event or alarm. PR120/K can also be used as actuator for the Load control function.

PR120/V Measurement module It measures and processes the phase and neutral voltages, are transferring these values to the protection release by means of its internal bus in order to achieve a series of protection and measurement features. It can be connected at any time to PR122/P, which recognizes it automatically without the need of any configuration. It’s standard supply for PR123/P. PR122/P and PR123/P do not normally require any external connection or Voltage Transformer, since it is connected internally to the lower terminals of Emax. When necessary, the connection of voltage pick-ups can be moved to any other points (i.e. upper terminals), by using the alternative connection located in the terminal box. The module is provided with a Power LED and a sealable switch-disconnector for the dielectric test.

PR120/D-M Communication module The communication module is the solution for connecting Emax to a Modbus network, allowing the remote supervision and control of the circuit-breaker. This module can be added at any time to the protection release and its presence is automatically recognized. It is provided with three LEDS on the front side: Power LED Rx/Tx LEDs

PR120/D-BT Wireless Communication module It is the innovative wireless communication module, based on Bluetooth standard. It allows the communication among the PR122/P and PR123/P protection release and a PDA or a Notebook with a Bluetooth port. This device is dedicated to the use with SD-Pocket application It is provided with four LEDS on the front side: Power LED Rx/Tx LEDs Bluetooth LED, showing the activity of Bluetooth communication PR120/D-BT can be connected at any time to the protection release