ABB REA101-AAA ARC PROTECTION

From: | Author:kongjiang | Time :2025-06-27 | 320 Browse: | Share:

Description

The REA system is a fast and flexible arc fault protection system for air-insulated low voltage and medium voltage switchgears. A fast and selective arc fault protection system is a natural constituent of a modern switchgear panel and a safety and security investment for older switchgears to protect human lives and prevent or reduce asset damage.

The REA arc fault protection system uses two types of sensors for detecting light: a non-shielded, bare-fiber sensor that detects light along its entire length and light collecting lens-type sensors with typically one sensor installed per switchgear compartment.

The function of the REA arc fault protection system is based on detecting the intense light of an electric arc alone or on a detection of light and simultaneous phase or neutral overcurrent. On detection of an arc fault, the REA arc fault protection system delivers trip commands in less than 2.5 ms to all circuit breakers that feed the fault zone. Furthermore, the operation indicators of the REA arc fault protection system help localizing faults by selectively guiding the maintenance staff to the fault zone, that was identified by the arc fault protection system.

The actual REA arc fault protection system consists of one or more arc fault protection main modules type REA 101 and a necessary number of extension modules type REA 103, REA 105 and REA 107. The main module REA 101 can operate as a stand-alone device or cooperate with other REA 101 modules, and with the REA 103, REA 105 or REA 107 extension modules. The extension modules REA 103 and REA 107 allow the number of sensor fibers and/or lens-type sensors to be increased to extend the area of protection. The use of the extension module REA 105 including fast trip outputs will allow protection schemes with increased selectivity to be created.

The arc flash phenomenon

The consequences of an arcing short-circuit or earth-fault inside a low voltage or medium voltage switchgear panel can be very disastrous. The extremely hot electric arc can destroy valuable equipment causing prolonged and costly distribution downtimes. Moreover, an arc fault poses a serious threat to the switchgear operating and maintenance staff.

An arc fault can arise from, for example, insulation faults and weaknesses, maloperation of a switchgear device, improper (loose) busbar or cable joints, overvoltage, corrosion, pollution, moisture, ferro-resonance (instrument transformers) and even ageing under electrical stress. Most of these fault reasons can be prevented by appropriate maintenance. Despite of all precautions, arc faults may be caused by human error, or by animals entering the switchgear panel.

Time is a critical parameter for the detection and minimization of the effects of arc faults as the arc incident energy rapidly increases by time. An arc fault lasting 500 ms may cause severe damage to the installation. If the arc lasts for less than 100 ms the damage is often restricted, but if the arc is extinguished in less than, for example, 4 ms the damage is insignificant.

Arc fault protection system

For all modules of the REA arc fault protection system the user can select either an automatic or manual compensation system for the ambient light. The compensation system enables adjustment of the sensitivity of the light detection in relation to the reference level based on the intensity of the ambient light measured by the sensors or on the value selected with a setting device on the front panel of the modules. The sensitivity adjustment eliminates the possibility of unwanted operation of the REA arc fault protection system, for example, when an air magnetic circuit breaker or a pole-switch disconnector is breaking current.

Arc fault protection module REA 101

The arc fault protection module REA 101 is the main module of the REA arc fault protection system. The REA 101 module can operate as a stand-alone device or in combination with other REA 101 modules and with the extension modules REA 103, REA 105 or REA 107. The REA 101 module is provided with two extension ports. A maximum of five extension modules can be daisy-chained to each port. Several REA 101 modules can be interconnected via a fiber-optic link communication or the intermediate REA 105 extension module can be used. The REA 101 module can utilize one loop or radial type fiber sensor, or a lens-type sensor for light detection

High speed trip outputs

1.The REA 101 module features two high-speed, galvanically isolated, insulated gate bipolar transistor (IGBT) outputs (HSO1 and HSO2) for CB tripping purposes. In addition, REA 101 offers one heavy-duty relay output (TRIP3) to be used, for example, as a circuit-breaker failure protection (CBFP) output for an up-stream circuit breaker, or as an alarm output. ABB Overcurrent condition The REA 101 module features an adjustable three-phase overcurrent or two-phase and neutral overcurrent condition monitoring function, which enhances the reliability of the arc fault detection by eliminating unwanted CB tripping caused by light not related to any arc fault, like a flash light used in photography.

Circuit-breaker failure protection The circuit-breaker failure protection is implemented by delaying either the HSO2 output or the TRIP3 output, or both, if required. Note that if both outputs are used, the delay time of both outputs is the same, but the pickup time of the electromechanical output relay (5...15 ms) must be added to the TRIP3 relay. The selected delay time, 100 ms or 150 ms, starts running, once the HSO1 output is activated. The delayed tripping does not take place if the overcurrent signal disappears before the specified time delay has elapsed. Fiber-optic link communication The REA 101 module contains two communication link terminals: Optolink 1 and Optolink

2. The purpose of the communication links is to send and receive ON/OFF type 6 1MRS756449 B messages between the main modules over a signal transfer fiber. One of the following selectable messages, LIGHT, OVERCURRENT or TRIP, can be transferred over a distance of max. 40 m, when plastic fiber cables (to be used with type REA101-AAA or REA101-CAA) or up to 2 km, when glass fiber cables (to be used with type REA101-AAAG) are used. Self-supervision The built-in self-supervision system of the REA 101 module continuously monitors the operating voltages, the integrity of the cabling between the main module and the extension modules, and the fiber-optic link connections between the main modules. Any fault or malfunction detected by the self supervision system will be used for alerting the operator. A detected fault will block the module to prevent incorrect operation.

Extension modules Extension module REA 103

REA 103 is an extension module to be used together with the main arc fault protection module REA 101. The REA 103 extension module is operating as a light detecting module in the REA arc fault protection system. REA 103 detects light and provides the operator with information about the location of the 2 GUID-D260D3EF-891E-435B-A75E-C61724D0F0FE V1 EN 1MRS756449 B fault. For light detection REA 103 can use two loop-type or radial sensor fibers. The built-in self-supervision system of the REA 103 module continuously monitors the operating voltages of the module and the continuity of the sensor fiber loops. Any fault or malfunction detected will be used for alerting the operator via the REA 101 main module.

Extension module REA 107

REA 107 is an extension module to be used together with the main arc fault protection module REA 101. The REA 107 extension module is operating as a light detecting unit in the REA arc fault protection system. REA 107 allows connection of up to eight lens-type sensors. The sensor input specific LED indicators of REA 107 facilitate fault location by guiding the staff to inspect the area of coverage of the sensor(s) that detected the arc. REA 107 is equipped with two alarm contact outputs, which enable the partition of the lens sensors into two groups. 8 The built-in self-supervision system of the REA 107 module continuously monitors the operating voltages of the device. Any fault or malfunction detected will be used for alerting the operator via the REA 101 module. A detected fault will block the device to prevent incorrect operation. The lens-type sensors are especially suitable for retrofit installations by providing a more convenient installation of the sensors compared to the fiber sensor solution.