Line-Based Charts

ZoomLine makes the classic line chart more interactive for time-, event-, or period-based analysis. Users can select a specific time range to zoom in, examine micro-level changes, and return to the overall view when necessary.

How It Works

• Main line / Overview: Displays the overall trend for a 24-hour period or a selected longer time range.
• Zoom area: Identifies the critical region using the mouse or a time-range selection.
• Detail view: Displays the selected range at high resolution, making peaks, drops, and oscillations visible.

Hydroelectric Power Plants

• Turbine loading and pressure: Joint examination of turbine power and penstock pressure during load pickup.
• Gate movements: Evaluation of the synchronization between gate opening, turbine power, and hydraulic oil pressure.
• Gate opening–flow rate: Analysis of the effect of gate movement on flow rate.
• Vibration and mechanical health: Investigation of early behavior in turbine/generator vibration and bearing temperatures.
• Flood and emergency conditions: Joint monitoring of inlet flow, spillway gate opening, and reservoir level during sudden events.
• Cavitation: Detailed examination of turbine speed, outlet pressure, and vibration behavior within the critical range.
• Synchronization: Evaluation of frequency, phase angle, and voltage changes in terms of turbine–generator–grid coordination.

Alarm and Event Analysis

Focused windows such as approximately 5 minutes before an alarm, the alarm moment, and approximately 10 minutes after the alarm can be selected to provide visual evidence for the question, “Why did this alarm occur?”

ZoomLineDY analyzes two physical quantities with different scales simultaneously on the same time axis, with synchronized zooming. The left and right Y axes use independent scales, while the X axis is shared.

• X: Common time axis.
• Left Y: First measurement; for example, active power (MW).
• Right Y: Second measurement; for example, frequency (Hz), temperature (°C), or pressure (bar).
• Zoom: Both signals are zoomed together within the selected time range.

Why Is It Valuable for HPPs?

Variables with different scales, such as level, flow rate, power, pressure, and vibration, can be examined together within the same time period. This reduces the visual scale loss that can result from using a single Y axis.

• Load–frequency: Left Y = active power (MW), Right Y = grid frequency (Hz). The frequency response during load pickup is examined.
• Generation–voltage: The relationship between voltage deviation and generation behavior is investigated through the MW ↔ kV relationship.
• Reservoir level–generation: Matching of water level and instantaneous generation power over time.
• Flow rate–power: Joint evaluation of water utilization conditions and generation power.
• Reservoir level–plant load: The relationship between water management and generation strategy over time.
• Penstock pressure–turbine power: Joint examination of hydraulic stress and load behavior.
• Gate opening–flow rate: Mechanical–hydraulic coordination analysis.
• Turbine speed–vibration: Mechanical health monitoring.
• Inlet flow–spillway gate response: Flood and emergency response behavior.

Line chart is a basic and powerful visualization tool that shows how a variable changes along a time or sequential axis. Data points are connected sequentially by lines.

Key Features

• Continuity perception: Shows how values follow one another and reveals process behavior.
• Trend analysis: Enables rapid identification of increasing, decreasing, stable, or fluctuating behavior.
• Readability: Provides a common and easily understandable visual language for operators, engineers, and managers.

• Turbine active power: Generation behavior and load changes over time.
• Dam level: Daily or monthly water-management and generation potential trends.
• Flow rate–generation: Comparison of turbine flow rate and active power using multiple lines.
• Vibration: Trend monitoring of turbine and generator bearings; generating data for predictive maintenance.
• Bearing and winding temperatures: Monitoring thermal limits.
• Gate opening–power: Evaluation of regulation-system behavior.
• Grid frequency–plant response: The response of the generation facility to grid events.
• Pre- and post-alarm trend: Comparison of behavior around an event.

Other facilities: Boiler temperature, steam pressure, and turbine speed can be monitored in thermal power plants; in renewable facilities, solar generation profiles, wind speed–generation relationships, and inverter output power can be monitored.

LogLine is a line chart type that uses a logarithmic scale on the Y axis instead of a linear scale. It is particularly useful when small and large values occur together within the same time series, increasing the visibility of small but potentially critical changes.

• Growth such as 1 → 10 → 100 → 1000 is represented across more balanced visual intervals on a logarithmic axis.
• Proportional changes can be perceived more intuitively.
• Early-stage failure indicators may be easier to identify when appropriate data and scale selection are used.

HPP Examples

• Cavitation indicators and pressure fluctuations.
• Reduction of generator insulation resistance from MΩ → kΩ → Ω levels.
• Low-flow–power behavior.
• Stator current peaks during start-up.
• Transitions in shaft-seal drainage flow rates from very small to large values.

Spline chart smooths the sharp corners between data points to present the overall trend in a more fluid manner. Curves are generated between points using interpolation approaches similar to Bezier or cubic splines.

Why Spline?

• It can reduce visual complexity caused by measurement noise.
• It can reduce the dominance of short-term fluctuations over the long-term trend.
• It helps readers perceive overall behavior more quickly.

HPP Applications

• Changes in dam water level.
• Flow rate–time and watershed response.
• Turbine power – controlled load pickup / load rejection.
• Turbine bearing and generator winding temperature trends.
• Water consumption – power generation trend.
• Average trend of multiple level sensors.