REIVAX replaces Basler SSE static excitation system, re-using the existing cabinet
Scope of Work
Reivax North America (REIVAX) has completed a static excitation upgrade of an aging Basler SSE equipment to the full satisfaction of the end-user.
The existing excitation system was part of a larger switchgear line-up and for this reason, the customer preferred to re-use the existing cabinet and have the new REIVAX static excitation system delivered on mounting panels for installation into the existing cabinet.
Unique Project Features
Due to the fact that the hydro plant was designed for variable flow and is lacking turbine flow regulation, the generator is started as a synchronous motor. This is achieved by closing the 52 grid-tie breaker at generator stand-still, causing the grid to increase the speed of the generator. A reduced voltage start is used in order to reduce the inrush current to the stator.
This starting method required the new REIVAX static excitation system to be designed to start as a synchronous motor and to operate as a synchronous generator once the start-up was complete.
A motor protection relay was added in the excitation system to monitor the stator current and the induced voltage on the field in order to close the field application relay (FAR) at the correct time.
A field contactor with 2NO main contacts and 1NC aux contact provided isolation of the excitation system during the start-up when high induced voltage was developed on the field as a result of the starting method.
Old Basler SSR static excitation system
The equipment included analog controls with separate devices for adjusting the excitation output, different limiters etc. Over time, these devices were affected by variations in ambient temperature, resulting in drifting of the potentiometer settings and since many of the control boards were not protected against dust, increased maintenance was required to maintain the accuracy of the controls.
Discrete components require more space. Due to this, the equipment layout of the existing system was not optimized for safety nor maintenance as the control and power components were mounted in close proximity to each other. Furthermore, analog controls make troubleshooting difficult since there are no diagnostics tools to pinpoint where a failure may reside.
These aspects along with the difficulty in finding replacement parts, drove the need to replace the Basler SSE system.
New REIVAX RTX Power static excitation system
REIVAX performed a set of detailed cabinet measurements to ensure that the new mounting panels would fit the existing cabinet. REIVAX provided a pre-installed wire harness for interconnecting wiring between the panels. The following panels were provided:
- • Control mounting panel (AVR, power supplies, motor protection and external control interface, etc.)
- • Power mounting panel (6-pulse rectifier bridge, input breaker, DC contactor 2NO/1NC, etc.)
- • Door panels (15″ HMI and air intake/exhaust)
With the new REIVAX solution, the control section is completely separated from the power section and mounted on the left side of the cabinet where the customer control interface also resides. The power section is fully mounted on the back panel.
The 15” touch screen HMI panel is operated from the front of the door and includes powerful diagnostics features which allow the customer to pinpoint the exact failure point. A sequence of event (SOE) is also available with 1ms time sampling which can be synchronized with SCADA signals using a satellite clock via IRIG-B.
The power section is over dimensioned as it is rated for 400Adc, while the rated field current is 224Adc. This will ensure a lower operating temperature, which will extend the overall life expectancy.
Customer Benefits
With the new REIVAX static excitation system the customer will enjoy a reliable operation for years to come and the reassurance of part availability and technical support if needed.
The same customer also has REIVAX static excitation systems at two (2) other power plants for a total of seven (7) units which have been in operation since 2016. The fact that REIVAX utilize the same excitation controller for large and small systems enabled the customer to have interchangeable spare parts between all power plants.
