From circuit breaker to power manager
18 August 2014
Rob McCaskie, ABB’s Product Manager for Power Circuit Breakers in the UK, explains how the firm’s new Emax 2 is a low voltage circuit breaker with power management capabilities.
Since ABB’s first forays into low voltage air circuit breakers in the late 1940s, there have been major improvements in both reliability and performance of devices. But with the market calling out for greater performance in a more compact design as well as enhanced control functionality, ABB recognised that the time had come for a major evolutionary step.
The Emax 2 is a brand new design of circuit breaker. At first glance, the most obvious difference with the original Emax design is its size and weight. An Emax 2 rated at 1,250 A weighs 32 kg versus the 60 kg of the Emax. And a user-friendly touch screen control interface has been introduced.
But the real difference is in the Emax 2’s full capabilities, which enable it carry out power management.
At the centre of the Emax 2, its Power Controller function has patented algorithm that determines average power consumption over time. It then uses a load list to take low priority loads offline and keep power usage below a maximum limit set by the user. By limiting maximum power, operators benefit from savings on electricity bills without the need to install additional monitoring systems.
Local monitoring of circuit breakers and switchgear functions are carried out through the Emax 2’s Ekip Link system and Ekip Control Panel. Included in even the most basic trip unit, the tools require no programming and provide an economic way to increase the monitoring capabilities on a small plant or simplify local supervision and maintenance on a larger plant.
A number of control and measurement features are built into the Emax 2, eliminating the need for external modules that require space and investment.
The built in Network Analyzer feature can analyze power quality in real time, with high precision in accordance with EN 50160 and IEC 6100-4 30 standards. It means that operators can identify the causes of increased power outages or reduced service life of cables and capacitors without having to install costly, external instrumentation.
Another module that eliminates the need for an independent external monitoring system is the Ekip Synchrocheck. It controls the synchronization condition, which places two lines in parallel before a circuit breaker can close.
Generator versions of the Ekip Touch and Ekip Hi-touch trip units include all the functions of true generator protection switchgear. Once again, there is no need for external relays or devices, wiring or inspections. The G version offers a safe control solution that is immediately ready for use.
Every Emax 2 can be equipped with multiple cartridge-type communication modules at any time. The modules integrate the circuit breakers directly into automation and energy management systems using the seven most popular global communication protocols; including IEC 61850 for the creation of Smart Grid Networks. All functions can be accessed via the web in complete safety using the Ekip Link switchgear monitoring system.
At the rear of the Emax 2, its terminals can be rotated from horizontal to vertical or vice versa through a simple procedure that can be carried out in the field. The terminals have also been specifically designed to fit the most common bus configurations. Each terminal has been created to the standard width of bus bar for its rated current and is equipped with one, two or three terminal stabs for easy connection of up to four bus runs. This arrangement provides easy connection and installation using a minimum of bus bar stock.
The Ekip Supply Module can be connected to any AC or DC voltage with no need for an external power supply converter, saving both space and cost. The module supplies auxiliary power for the trip units and terminal box modules.
More flexibility is built into the Emax 2 by the ability to modify the neutral position from left to right. In addition, the E6.2 model is available with neutral conductor sizes of 50 percent or 100 percent to allow for correct bus bar sizing and give an option to reduce construction costs.
Four frame sizes are available in the Emax 2 range, each of which is no wider than required by its current rating, a consideration which minimizes its width. It also means that panel designers can optimize their use of space and material. The breaker design and its use of quality materials allows for a small size while maintaining the high performance required by the most demanding conditions.
The four Emax 2 models are:
− E1.2, 1600 A with a 440 V Icu of 66 kA and Icw 1s of 50 kA in a 210mm width.
− E2.2, 2500 A with a 440 V Icu of 100 kA and Icw 1s of 85 kA in a 276mm width.
− E4.2, 4000 A with a 440 V Icu of 150 kA and Icw 1s of 100 kA in a 384mm width.
− E6.2, 6300 A with a 440 V Icu of 200 kA and Icw 1s of 120 kA in a 762mm width.
New generation Rogowski sensors are integrated into the Emax 2 for extremely precise measurements of current, voltage, power and energy. Tolerances are to 1 percent of the actual value of current, 0.5 percent of voltage and 2 percent of power and energy. This guarantees precision and enables the circuit-breaker to act as a measurement device in switchgear. Measurements can be read directly on the trip unit display so additional devices can be eliminated.
Because the Ekip Fan Module continuously monitors the internal temperature of the fixed switchgear part and activates cooling fans if required, ABB has been able to increase the current-carrying capacity of the Emax 2.
Simplicity and safety
As the Emax 2 is the first circuit breaker to offer a large, colour touchscreen display, it has clear, easy navigation for quick access to information and
adjustment capability that is invaluable in the event of a fault or emergency.
The trip units can be used in 10 languages, reducing the need for extensive training. In addition, they can be read and used directly, without the need for an expensive HMI (human machine interface) unit. They can also be programmed and accessed using a tablet, smart phone or PC through the Ekip Connect application.
An accessory mounting area is accessible by removing the Emax 2’s main cover. This compartment is isolated from the operating mechanism and other components for safety of maintenance personnel and the breaker itself. A key lock accessory inside the accessory area allows for the breaker to remain locked, avoiding unwanted operation during maintenance.
Dedicated guide rails simplify movement and allow correct, lockable and clearly identifiable positioning. The rails extend outside the fixed part of the Emax 2 so that its mobile part can be easily inserted. Shutters on the fixed part can be locked from the front, protecting the interior and allowing easy and safe installation and maintenance.
ABB’s DOC software and Ekip Connect interface are used to input and amend breaker settings. Curves and settings can be determined and saved using the DOC software and the Ekip Connect program, eliminating the need to retype the settings into the breaker or software program and allowing for easy, error free implementation.
Emax 2 contains push in terminal box technology, making wiring easy and tooling-free. This feature ensures immediate, safe wiring. In addition, Emax 2 terminal boxes and wiring set ups are common across the line and its trip units are field interchangeable, creating flexibility and the potential for easy, rapid upgrades without the added cost of a service technician.
Award winning design
The quality of the Emax 2’s design was recognised in March 2014, when the product was awarded the Red Dot Product Design Award (red-dot.org), which is an international award to companies that achieve excellence in product design. The prestigious awards have been running since 1954 and was awarded to ABB because of the potential of the Emax 2 achieve annual energy savings equivalent to the consumption of 1.4 million European households, or 5.8 million megawatt-hours.
Full speed ahead for ferryboat
One of the earliest applications for Emax 2 is aboard a state-of-the-art diesel-electric ferryboat that was equipped by Italian electromechanical construction specialist IMESA.
During its contract, IMESA had the role of creating a switchgear column to feed the vessel’s main distribution system and motors and its customer set four strict criteria.
The first two requirements were for it to be fully selective with downstream circuit breakers and offer a short-circuit breaking capacity of 50 kA at 600 V AC. The second two requirements were for a horizontal bussing distribution system that needed to be as compact as possible to fit inside the vessel’s switchroom, and it also needed to be compatible with withdrawable circuit breakers.
Together, these four criteria set a tough challenge. The first two call for a category B circuit breaker, while the third and fourth would fit the profile of a moulded-case circuit breaker, which can be mounted in a horizontal position and is compact in size.
IMESA turned to the Emax E1.2, which is the only technology that was able to meet all of the requirements. Its terminal can be mounted either horizontally or vertically and it can break up to 66 kA at 440 V AC or (crucially in the case of IMESA’s installation) 50 kA at 690 V AC and it is able to withstand 50 kA for one second.
A total of five Emax 1.2 units were installed on the ferryboat. The installation also includes the optional add-on module Ekip Measuring, which measures voltage and voltage-related data including power, energy, power factor and frequency.
Building on the trip units, each air circuit breaker is also equipped with an Ekip Multimeter, which is a 96 mm touch screen display that displays measurements on a larger screen. Connected to the trip units, the Ekip Multimeters enable the parameters and protection thresholds to be adjusted onboard.
One single column houses all five individual Emax 1.2 units. At just 210 mm wide, the solution is 45 percent smaller than a comparable column of first generation Emax switchgear or of other products that are available on the market today.
The installation on the ferryboat is just one example of how the Emax 2 can deliver high performance and enhanced control in a compact and lightweight unit. By fitting into the tight parameters on board the ferryboat, the Emax 2 has freed up space that the operator can use to integrated additional electrical distribution equipment or other equipment, or even free up space for passengers.
For more information, please contact:
ABB Low Voltage Products and Systems
Foleshill Enterprise Park
Tel: 02476 368 500