Test Case TC01

Version management

Author

OCT

Version

2

Project

ERIGrid 2.0

Date

03/05/2021

Narrative

The aim of this test case is to prove that an on-load tap changer controller “OLTC” is able to regulate the voltage level of the distribution network to the required value as stipulated both by international standards and by the network operator. This regulation would happen when the components connected to its low voltage side or when external anomalies such as the weather disturbing the normal behavior of the grid voltage. Depending on the control strategy, the measured value could come from locally measured values, remotely measured values, or even from end-user (smart meter) measurements.

Function(s) under Investigation (FuI)

The function under test is the voltage level control

Object under Investigation (OuI)

• OLTC controller
• The communication infrastructure between the controller and the RTU.
• Flexible loads and sources on the demand side

Domain under Investigation (DuI)

Electric Power System, Communication, Control

Purpose of Investigation (PoI)

Verify if the performance of OLTC controller is adequate to maintain the voltage level within the required limits Characterize the OLTC operating performance in terms of loss reduction and hosting capacity enhancement.

System under Test (SuT)

The SuT is composed real experimental grid with the follow-ing components:

• Generator.
• OLTC
• Transformers.
• automated switchgear with RTUs.
• Controllable loads
• Communication facilities

Functions under Test (FuT)

• OLTC controller regulating the voltage.
• Communication of ICT with the RTU.
• Interaction of the OLTC with the SuT configuration and conditions.
• Loads and generation control.

Test criteria (TCR)

The OLTC shall be able to control voltage with the pre-established limits in a predefined time-frame.

Target Metrics (TM)

• Voltage (V) on low-voltage side of transformer.
• Operation time (s).
• Number of TAP position changes.

Variability Attributes (VA)

• Voltage variation.
• Control of loads and generation
• Errors in measurement
• Errors in Communication
• Loss of a line/generator

Quality Attributes (QA)

• Complies with the quality standards,
• Maintain voltages within the ±10% specified limit.

Qualification Strategy

The different tests will create situations where there is a significant variability in voltage in the test circuit setup. The PoI will be met when it is verified that the variability is controlled, and the voltage maintained within the limits set out by the corresponding standards.