⚡ electrical engineering

From Static Tables to Predictive Twins: Field-Validated Forecasting of V2G-Induced Insulation Thermal Aging in Residential Switchboards under VDE-AR-N 4100, with a Retrofit Pathway for Peru

This paper presents a field-validated multi-physics digital twin that quantifies V2G-induced insulation thermal aging in residential switchboards under German VDE-AR-N 4100 standards and translates these findings into a concrete regulatory and technical retrofit pathway for safely deploying V2G technology in Peruvian low-voltage networks.

Original authors: PAUL RICARDO PRUDENCIO GALVEZ

Published 2026-07-06

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: PAUL RICARDO PRUDENCIO GALVEZ

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

The Big Picture: The "Digital Twin" of Your Home's Wires

Imagine your home's electrical wiring is like a network of roads. Usually, cars (electricity) only drive in one direction: from the power plant to your house. But with V2G (Vehicle-to-Grid) technology, your electric car can also drive backward, sending electricity from your car back into your house or the neighborhood grid.

The problem is that this "two-way traffic" creates extra heat and stress on the roads (the wires), causing them to wear out faster. This paper introduces a Digital Twin—a virtual, computer-simulated copy of your home's electrical system—that acts like a "crystal ball" to predict exactly how fast these wires will wear out before they actually break.

The Problem: Old Maps vs. New Traffic

The author, Paul Ricardo Prudencio Galvez, points out a major gap:

The Old Maps: Current rules in Peru (and many other places) are like old road maps. They were drawn when cars only drove one way. They tell you how big a wire needs to be for a standard lightbulb or TV, but they don't know how to handle the extra stress of an electric car pushing power back into the system.
The Missing Link: Scientists have studied how wires age in labs, and they have studied how cars affect the grid, but no one had combined these two ideas into a single, real-world test to see how fast the insulation (the plastic coating on the wires) actually melts or cracks under this new "two-way" traffic.

The Solution: A Virtual Time Machine

The author built a Multi-Physics Digital Twin. Think of this as a highly sophisticated video game simulation that runs in real-time. It combines three different "worlds" into one model:

The Traffic Flow: It calculates the electricity moving back and forth, including the "bumps" and "jitters" (harmonics) that happen when power flows in reverse.
The Heat Engine: It simulates how that electricity turns into heat, warming up the wires just like friction heats up a car's brakes.
The Aging Clock: It uses a famous scientific formula (the Arrhenius model) to act as a stopwatch. It predicts how many years of life the plastic coating on the wire loses for every degree of extra heat it experiences.

The Test Drive: Germany to Peru

To prove this "crystal ball" works, the author did two things:

1. The German Test Drive (Validation)
They took this digital model and compared it against a real house in Germany that had been monitored for a year. The house had real electric cars charging and discharging.

The Result: The digital twin was incredibly accurate. It predicted the temperature of the wires within 1.7°C of the real sensors. It was like guessing the weather and being off by only a tiny fraction of a degree.
The Discovery: Even when following strict German safety rules, the "two-way" traffic still shortened the life of the wire's insulation by 18% to 34%. It's like driving a car on a rough road; even if you follow the speed limit, the tires still wear out faster than on a smooth highway.

2. The Peru Transfer (Application)
The author then asked: "Can we use this same model for homes in Peru?"
They ran the simulation for three Peruvian cities (Lima, Arequipa, and Cusco) with different weather and wiring sizes.

The Findings: In Lima, many existing homes have wires that are too thin (like a narrow alleyway) for this new traffic. If you plug in a V2G car, the wires get too hot (over 70°C), and the plastic coating starts to fail, which is a fire risk.
The Roadblocks: The study found three main reasons why this is risky in Peru right now:
- Undersized Wires: The wires are too thin for the extra load.
- Wrong Safety Switches: Current safety switches in Peru only detect AC electricity (one-way), but V2G creates DC electricity (two-way) that these switches can't "see" or stop.
- Uncoordinated Traffic: The system doesn't manage when the cars charge or discharge, causing traffic jams (harmonics).

The Fix: A Retrofit Pathway

The paper doesn't just point out problems; it offers a "repair manual" for Peru to safely adopt this technology:

Update the Rules: Change the wiring tables in Peru's electrical code (CNE-S) to account for "cyclic" (back-and-forth) loads, not just one-way loads.
Better Safety Switches: Mandate the use of Type-B Residual Current Devices. Think of these as "super-sensors" that can detect the tricky two-way electricity that standard sensors miss.
Smart Monitoring: Install small, low-cost computers (edge nodes) in the electrical panel that act as the "Digital Twin" in real life, constantly checking the wire temperature and warning if it gets too hot.

The Bottom Line

This paper proves that we can now use a computer model to predict exactly how electric cars will age the wires in our homes. It shows that while V2G is great for the grid, it puts extra stress on old wiring. For Peru to adopt this safely, they need to upgrade their wiring rules, install smarter safety switches, and use these digital models to check their homes before the wires burn out.

Technical Summary: From Static Tables to Predictive Twins

Problem Statement
The rapid adoption of bidirectional Vehicle-to-Grid (V2G) charging introduces complex stressors to residential low-voltage networks, specifically superimposing harmonic currents and cyclic thermal loads on existing conductors. While unidirectional charging injects harmonics, V2G adds reverse power flows and asymmetric phase loading, accelerating the thermal aging of Cross-Linked Polyethylene (XLPE) and Polyvinyl Chloride (PVC) insulation.

A critical gap exists in current engineering practice:

Regulatory Disconnect: Germany's VDE-AR-N 4100 and VDE 0100 standards provide explicit thermal and protection requirements for cyclic loading, whereas Peru's Código Nacional de Electricidad – Suministro (CNE-S), while adopting IEC 60364, relies on static conductor-sizing tables (Sección 030) never validated against bidirectional V2G duty profiles.
Research Fragmentation: Existing literature treats these domains in isolation. Building-level digital twins model energy flows but ignore conductor-level aging; V2G grid-impact studies quantify voltage and harmonics but treat insulation lifetime as negligible; and classical insulation-aging studies (Arrhenius models) remain confined to laboratory settings without field validation under real smart-grid loads.

Methodology
The study develops and field-validates a multi-physics digital twin that couples electromagnetic, thermal, and aging models at sub-minute resolution. The architecture consists of four synchronized modules:

Power-Flow Sub-model: Samples bidirectional current ( $I(t)$ ) at 1-second intervals, decomposing it into fundamental and harmonic components (up to the 50th order) per IEC 61000-2-2, accounting for frequency-dependent skin and proximity effects.
Thermal Sub-model: Utilizes a five-node lumped-parameter Cauer network to solve transient heat-balance equations. Thermal resistance ( $R_{th}$ ) and capacitance ( $C_{th}$ ) are calibrated from manufacturer datasheets and validated against physical RTD sensor networks.
Aging Sub-model: Applies the Arrhenius relation (IEC 60216) to estimate insulation lifetime ( $L$ ) based on hotspot temperature ( $T_{hotspot}$ ). Activation energies ( $E_a$ ) are set at 1.05 eV for XLPE and 0.92 eV for PVC.
Synchronization: A Kalman filter updates the model state every 60 seconds using field data to correct drift between physics-based predictions and ground truth.

Validation and Scenarios

Field Validation: The twin was cross-validated against 41 measurement points (1-second resolution) from a fully instrumented German demonstration dwelling operating over 12 months (2023–2024).
Transfer Study: The validated model was applied to 18 physics-based scenarios in Peru (Lima, Arequipa, Cusco) under CNE-S supply conditions. These scenarios varied conductor cross-sections (2.5, 4, 6 mm²), ambient temperatures, V2G penetration levels (10–50%), and tariff-driven charging schedules.
Statistical Rigor: Results utilized 5-fold cross-validation with a fixed random seed. Uncertainty was propagated via 95% confidence intervals (Student-t), with metrics including MAE, RMSE, $R^2$ , and MAPE.

Key Results

Model Accuracy: Against independent German field data, the twin predicted conductor hotspot temperatures with a Mean Absolute Error (MAE) of 1.7°C (95% CI: 1.4–2.0°C), an RMSE of 2.3°C, and an $R^2$ of 0.94.
Insulation Degradation: Under VDE-AR-N 4100-compliant V2G duty cycles, the model estimates an 18–34% reduction in XLPE insulation service life compared to static loading assumptions.
Peruvian Scenario Outcomes:
- Non-Compliance: In Lima, a 2.5 mm² conductor with 50% V2G penetration reached a hotspot of 82.1°C, exceeding the 70°C limit and resulting in a 41% lifetime reduction.
- Compliance via Retrofit: Correctly upsizing conductors (e.g., to 6 mm²) and implementing coordinated Distributed Energy Resource (DER) management kept temperatures within limits (e.g., 64.8°C in Cusco), reducing lifetime loss to 11%.
Identified Barriers: The study pinpointed three technical barriers for Peru: undersized conductor cross-sections, the absence of DC-sensitive residual-current protection, and uncoordinated demand-side harmonics.

Significance and Contributions
The paper claims to close the documented gap between V2G grid-impact studies, laboratory-only aging research, and cross-jurisdictional regulatory validation. Its primary contributions are:

A Validated Multi-Physics Twin: The first model to integrate harmonic power-flow, lumped-parameter thermal dynamics, and Arrhenius aging at sub-minute resolution, validated against real-world V2G field data.
Quantitative Evidence: Providing empirical data that V2G operation, even when compliant with current German standards, causes non-negligible insulation degradation (18–34% life reduction), challenging the assumption that standard compliance guarantees long-term safety.
Regulatory Transfer Framework: A reproducible pathway for adapting VDE-AR-N 4100 provisions to Peru's CNE-S. This includes specific, actionable recommendations:
- Harmonizing CNE-S Sección 030 with IEC 60364 cyclic-load provisions.
- Mandating Type-B Residual Current Circuit Breakers (RCCBs) to detect DC components.
- Phased pilot deployment in Lima and Arequipa using edge-computing nodes to monitor V2G circuits in real-time.

The study concludes that the barrier to safe V2G adoption in Peru is not a lack of technical principles (which exist in IEC 60364) but the absence of V2G-specific sizing tables, protection mandates, and coordinated management tools, all of which this digital twin framework makes quantifiable.