KATflow 200 – Reliable flow measurements in turbulent environments

When withdrawing water from watercourses, hydroelectric power stations are subject to specified maximum limits, which are required to generate a certain amount of electricity. As the plant ages, it becomes increasingly difficult to accurately determine these maximum withdrawal volumes when the original plant parameters (e.g. pumping capacity) change due to the ageing of the power station. In summary, this usually results in reduced efficiency. In particular, ageing hydroelectric power stations require a higher water flow rate to generate a specific amount of energy.

Katronics’ Italian sales partner, Selemark, was approached at a trade fair by an engineer from a power station group. The engineer explained that the turbines in the group’s hydroelectric power stations had been in operation since the 1950s and that, due to the higher water flow rate now required to meet generation targets, there was a risk that the power stations might lose their operating licences. In preparation for a planned refurbishment, the customer required a flow measurement solution that could be implemented without interrupting power generation – in other words, whilst the process was still running.

Katronic’s portable ultrasonic flow meter, the KATflow 200, fitted with the compact K1 sensors, was used for the feasibility study subsequently initiated. The sensors were mounted on the pipe using coupling paste and metal chains. The Acoustic Sensor Positioning Assistant, which is supported by all Katronic ultrasonic flowmeters, enables the user to mount the transducers on pipework quickly, effortlessly and precisely, so that a measurement can be started immediately with the best possible signal strength.

The outdoor iron pipes installed at the hydroelectric power station in question have a diameter of 650 mm and run uphill at a typical angle of 27°. The mountainous terrain meant that ambient temperature fluctuations were expected to range between –20 °C and +35 °C. Due to the heavy rust deposits found, the roughness of the pipe’s inner surface was estimated to be up to 4 mm. The flow rate through the pipes is typically 1.0 m^³/s, and the customer required the most accurate possible flow measurement, together with a reliable alarm should the flow rate exceed the withdrawal limit of 1.5 m^³/s.

The anticipated amount of rust on the inside of the pipework and a predicted flow velocity of between 3.1 and 4.9 m/s suggested higher levels of turbulence and, consequently, significant noise in the measurement signal. The KATflow 200’s advanced signal processing compensated for both factors perfectly. The flow rate measurement stabilised immediately and delivered excellent results. A customer engineer was able to confirm Katronic’s ultrasonic flow measurements on site by comparing the simultaneous variation in flow rate within the known percentage range and verifying the meter’s performance.

In this application, Katronic enabled a group of small hydroelectric power stations in Italy to remain within their permitted withdrawal limits. The KATflow 200, a non-invasive, portable clamp-on flow meter that is easy to install on cast-iron inlet pipes, provided a first-class solution for reliably and accurately measuring the water flow into the generator unit whilst the power station was operating normally.

Following this successful trial, the energy supplier is expected to purchase up to 30 KATflow flowmeters for the project, which is due to be completed within a year.

Image credit: Selemark