Accurate forecasting of electricity production is essential for maintaining the operational efficiency and strategic planning of energy utilities. In industrial settings, such forecasts are generated daily to ensure supply-demand balance and optimal management of production assets. However, the increasing complexity of modern power systems and data flows poses significant challenges for ensuring the reliability and consistency of these forecasts. This paper addresses the problem of anomaly detection in short-term production forecasts at EDF, formulated as identifying atypical intra-day patterns that may signal data quality issues or operational irregularities. We introduce TAMIS, a scalable and interpretable system that analyzes daily production time series to automatically detect anomalous days based on deviations from historical patterns learned from past data. Designed for human-in-the-loop workflows, TAMIS surfaces top-ranked anomalies through an automated daily newsletter, enabling efficient expert review and continuous monitoring. An extensive experimental evaluation on real-world industrial data demonstrates that TAMIS achieves the best accuracy-efficiency trade-off compared to baseline methods. To foster further research and reproducibility, we publicly release the anonymized application datasets used in our study.
Figures & tables
Fig. 1 : Examples of time series in our proposed JO dataset (anomalies are highlighted in red).
Symbol
Description
Δ∈N
Sampling interval ( 30 minutes).
M∈N
Number of samples per day ( M=48 ).
Cd∈RM
Daily window (24-hour profile) for day d
cm∈R
m -th value of Cd
Fd∈Ri
Feature set for day d
fj∈R
j -th value of Fd
TABLE I : Summary of main notations used in this paper.
Fig. 2 : Raw-based Time series anomaly detection methods in the literature [ 9 ]
Fig. 3 : Example of TSFresh and Catch22 features on IOPS [ 25 ] time series.
Fig. 4 : Time series anomaly detection: from unique detector (a) to supervised ensembling (d).
Fig. 5 : (1) Training and (2) production pipeline of the proposed solution TAMIS . The end-user interface is illustrated in (3).
Feature Description
Formula
Complexity
Expert-based : Top-10 features from energy-production expert-knowledge
amplitude: maximum amplitude for a given window Cd .
max(Cd)−min(Cd)
O(n)
val max: Maximum value in Cd .
max(Cd)
O(n)
val min: Minimum value in Cd .
min(Cd)
O(n)
val mean: Mean of Cd .
μ(Cd)
O(n)
val std: Standard deviation of Cd .
σ(Cd)
O(n)
TABLE II : TAMIS F features. Each feature is computed for an entire window (i.e., day d ). Note: I(p) is the indicator function for NaN values. ΔCd represents first-order differences. Vreocc. is the set of reoccurring values in CD .
Characteristics
JO
HYDRAU
THERM
Number of sensors
3198
1740
4515
Total number of measurements
219M
267M
103M
Number of Labeled days
5813
540
578
NaN ratio
20.3%
3.5%
27.9%
Total number of NaN
55334
640
7827
Number of Anomalies
307
57
12
TABLE III : Datasets characteristics. NaN ratio: number of labeled days with at least one NaN value.
Fig. 6 : Precision-Recall curves of TAMIS against (a) detectors on raw data; (b) detectors on TAMIS F feature set; (c) Automatic solutions (Model Selection and Ensembling). (d) Throughput versus AUC-PR for TAMIS against most competitive baselines.
Fig. 7 : Comparision of AUC-PR versus throughput between TAMIS using TAMIS F , Catch22 and TSFresh as feature sets. The throughput corresponds to (a) Features computation, (b) Detectors computation, and (c) weights inference.
Methods
JO
HYDRAU
THERM
Detectors on raw time series
HBOS
0.069
0.297
0.041
LOF
0.228
0.226
0.072
OCSVM
0.138
0.143
0.028
Detectors on (TAMIS F features)
HBOS
0.656
0.596
0.191
TABLE IV : Accuracy (AUC-PR) of TAMIS and baselines applied on raw data and TAMIS F features.
Fig. 8 : Comparison of our proposed approach TAMIS versus baselines on different models in-distribution (trained and tested on JO dataset) and two out-of-distribution scenarios. Note that all f. and r. stands for all features and raw .
Fig. 9 : TAMIS vs Best Detector, Avg Ens, the Best Model Selection strategy and the theoretical Oracle on TSB-UAD [ 11 ] .