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arxiv: 1907.00339 · v1 · pith:K4SNOFZFnew · submitted 2019-06-30 · 📡 eess.SY · cs.SY· eess.SP

Design and Implementation of an Automatic Synchronizing and Protection Relay through Power-Hardware-in-the-Loop (PHIL) Simulation

Mishal Mahmood , Mariam Azam , Khair-un-Nisa Fatima , Muhammad Sarwar , Muhammad Abubakar , Babar Hussain This is my paper

Pith reviewed 2026-05-25 12:47 UTC · model grok-4.3

classification 📡 eess.SY cs.SYeess.SP
keywords synchronizing relaydistributed generatorPHIL simulationLabVIEWArduinoblack-start synchronizationprotection relayvoltage and frequency control
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The pith

An automatic relay synchronizes a distributed generator to the grid from black-start by controlling voltage and frequency on a lab-scale synchronous generator.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper describes the design of a multi-purpose synchronizing and protection relay for connecting distributed energy resources to the main grid. The relay uses low-cost Arduino hardware for data acquisition together with LabVIEW software to manage the process. Frequency matching occurs through speed control of a stepper motor acting as prime mover, while voltage matching uses an excitation control module within a Power-Hardware-in-the-Loop setup. The same relay also provides active and reactive power control plus protection functions once the generator is grid-connected. The authors report that the complete system was built and tested on a laboratory test bed.

Core claim

The paper claims that a synchronizing relay built from Arduino data acquisition and LabVIEW software can automatically bring a lab-scale synchronous generator from black-start into synchronism with the utility grid by simultaneously regulating frequency via stepper-motor speed and voltage via excitation control inside a PHIL simulation, while also supplying grid-connected power control and protection, and that the resulting relay satisfies the utility-imposed synchronization requirements.

What carries the argument

The multi-purpose synchronizing relay implemented with Arduino data acquisition and LabVIEW software that performs frequency synchronization via stepper-motor speed control and voltage synchronization via excitation control inside a PHIL simulation.

If this is right

  • The relay can perform synchronization from a black-start condition.
  • Once connected, the same relay implements active and reactive power control for the generator.
  • Protection schemes for the synchronous generator operate in grid-connected mode.
  • The complete design was validated on a physical lab-scale test bed.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Low-cost microcontroller and software combinations may allow similar relays to be replicated for small distributed resources without custom hardware.
  • The PHIL approach could be extended to test synchronization logic against recorded utility disturbance waveforms before field deployment.
  • Adding communication interfaces to the relay would enable coordinated synchronization of multiple generators in a microgrid.

Load-bearing premise

The lab-scale test bed and PHIL simulation accurately represent real utility grid conditions and requirements.

What would settle it

A direct connection test on an actual utility feeder in which the relay either fails to achieve voltage and frequency match within the utility limits or trips the protection during the synchronization sequence.

Figures

Figures reproduced from arXiv: 1907.00339 by Babar Hussain, Khair-un-Nisa Fatima, Mariam Azam, Mishal Mahmood, Muhammad Abubakar, Muhammad Sarwar.

Figure 1
Figure 1. Figure 1: shows a block diagram in which a synchronous generator is used to model the connecting source with the grid [9], [10]. It is modelled with its mechanical power provided Excitor DC Field Excitation Turbine Mechanical Power Stabilizer Speed Deviation Terminal Voltage Transducer Regulating Signals Synchronous Generator [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Block diagram for speed synchronization B. Frequency Synchronization Frequency control is the most important task regarding syn￾chronous machine operation in real time. Using (1), one can get the value of the desired speed required by the synchronous generator to get synchronized with grid. v = 120f /P (1) v is the speed of prime mover. P is the number of poles of the synchronous generator. f is the requir… view at source ↗
Figure 4
Figure 4. Figure 4: Front panel for speed control in LabVIEW [PITH_FULL_IMAGE:figures/full_fig_p003_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Excitation Module [PITH_FULL_IMAGE:figures/full_fig_p003_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Voltage control loop block diagram [PITH_FULL_IMAGE:figures/full_fig_p004_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Block diagram for voltage control in LabVIEW [PITH_FULL_IMAGE:figures/full_fig_p004_7.png] view at source ↗
Figure 10
Figure 10. Figure 10: Phase synchronization block diagram. Turn on the prime Mover to provide mechnical power to generator. Meter the frequency and voltage of grid Start Calculate required speed of Prime Mover Speed Control loop achieves the required speed by PID controller Turn on the Excitation system to provide field current to generator End Plot the phase difference between grid and generator phases Synchronize the frequen… view at source ↗
Figure 11
Figure 11. Figure 11: Flowchart of the auto-synchronization process. [PITH_FULL_IMAGE:figures/full_fig_p005_11.png] view at source ↗
Figure 13
Figure 13. Figure 13: Protection scheme front panel in LabVIEW. [PITH_FULL_IMAGE:figures/full_fig_p006_13.png] view at source ↗
Figure 14
Figure 14. Figure 14: Experimental setup of working system. VI. CONCLUSIONS This paper has proposed an auto-synchronization relay which automates the process of synchronization of a Dis￾tributed Generator with the grid and makes the process easier, safer, cost-effective and reliable. In the software, custom auto-syncing modules have been developed successfully. A test bed system has been designed which is useful for the operat… view at source ↗
read the original abstract

This paper focuses on the design and implementation of an automatic synchronizing and protection relay to automate the synchronization process of a Distributed Energy Resource (DER) to the Main Grid. The proposed design utilize a cost-effective data acquisition using arduino in combination with LabVIEW software to implement the multi-purpose synchronizing relay. The proposed synchronizing relay is capable of synchronizing a Distributed Generator (DG) to the power grid from black-start and fulfills the requirements imposed by the utility. The synchronizing relay is implemented through voltage and frequency control of an actual lab-scale synchronous generator. In the synchronization process, frequency synchronization is done using speed control of the stepper motor as prime mover and voltage synchronization is accomplished using Excitation Control module through Power-Hardware-in-the-Loop (PHIL) simulation. In grid-connected mode, active and reactive power controls and protection schemes for the synchronous generator have also been implemented. The proposed multi-function relay has been deployed and tested on a lab-scale test bed to validate the proposed design and functionality.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper describes the design and implementation of a cost-effective automatic synchronizing and protection relay for a distributed generator (DG) using Arduino-based data acquisition combined with LabVIEW. Frequency synchronization is achieved via stepper-motor speed control of the prime mover and voltage synchronization via an excitation control module in a Power-Hardware-in-the-Loop (PHIL) setup on a lab-scale synchronous generator. The work claims that the relay successfully synchronizes the DG from black-start, fulfills utility requirements, and additionally implements active/reactive power control and protection functions in grid-connected mode; the design is stated to have been deployed and tested on a lab-scale test bed.

Significance. If quantitative validation data were supplied, the work would demonstrate a practical, low-cost hardware implementation of a multi-function relay suitable for DER integration. The PHIL-based excitation control provides a realistic test environment that could be of interest for control-hardware validation studies. At present the absence of performance metrics prevents assessment of whether the claimed utility compliance has been achieved.

major comments (2)
  1. [Abstract] Abstract: the central claim that 'the proposed synchronizing relay ... fulfills the requirements imposed by the utility' is unsupported by any reported measurements of voltage difference, frequency difference, phase-angle difference at breaker closure, synchronization success rate, or direct comparison against IEEE 1547 or utility tolerances.
  2. [Abstract / validation description] The manuscript states that the relay 'has been deployed and tested on a lab-scale test bed to validate the proposed design and functionality,' yet no tables, figures, or numerical results (e.g., ΔV, Δf, Δθ statistics, protection trip times, or black-start test outcomes) are supplied to substantiate this validation.
minor comments (2)
  1. Clarify the exact utility standards or numerical tolerances referenced (voltage, frequency, phase-angle windows) so that readers can judge compliance.
  2. The description of the PHIL interface and stepper-motor control loop would benefit from a block diagram or timing diagram showing signal flow between Arduino, LabVIEW, and the generator.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive feedback highlighting the need for quantitative validation metrics. We agree that the current manuscript does not include the requested performance data and will revise it accordingly to strengthen the claims.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the central claim that 'the proposed synchronizing relay ... fulfills the requirements imposed by the utility' is unsupported by any reported measurements of voltage difference, frequency difference, phase-angle difference at breaker closure, synchronization success rate, or direct comparison against IEEE 1547 or utility tolerances.

    Authors: We acknowledge that the abstract's claim regarding utility compliance lacks supporting quantitative evidence in the submitted version. In the revised manuscript, we will add specific measured values for ΔV, Δf, and Δθ at the moment of breaker closure, synchronization success rates from multiple trials, and direct comparisons against IEEE 1547 tolerances and typical utility requirements. These will be drawn from the existing experimental records of the PHIL-based tests. revision: yes

  2. Referee: [Abstract / validation description] The manuscript states that the relay 'has been deployed and tested on a lab-scale test bed to validate the proposed design and functionality,' yet no tables, figures, or numerical results (e.g., ΔV, Δf, Δθ statistics, protection trip times, or black-start test outcomes) are supplied to substantiate this validation.

    Authors: We agree that the validation description is not supported by numerical results or figures in the current manuscript. The revised version will include new tables and figures presenting ΔV, Δf, Δθ statistics, protection trip times, and black-start synchronization outcomes from the lab-scale PHIL experiments to substantiate the deployment and testing claims. revision: yes

Circularity Check

0 steps flagged

No circularity: hardware implementation paper without derivations or self-referential predictions

full rationale

The paper is a descriptive account of designing and testing a synchronizing relay on a lab-scale synchronous generator using Arduino/LabVIEW and PHIL simulation. No equations, parameter fitting, predictions, or derivation chains appear in the provided text. The central claim rests on the physical implementation and qualitative validation on the test bed rather than any reduction of outputs to inputs by construction. Self-citations, if present, are not load-bearing for any mathematical result. This is a standard non-circular engineering implementation report.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No free parameters, axioms, or invented entities are introduced because the paper reports an engineering implementation rather than a theoretical derivation.

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Reference graph

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