Data in Brief

This article presents a dataset for a Norwegian industrial medium voltage (MV) and low voltage (LV) electric power distribution grid with load time series. The raw dataset was col- lected in collaboration with the Norwegian distribution grid company (DSO 1 ) Norgesnett as part of a pilot project in the Norwegian research centre CINELDI and was later anonymized and simpliﬁed into a secondary dataset, presented here. The load dataset comprises over three years of measurements of hourly load demand from 45 grid customers in the time pe- riod 2019-03-01 to 2022-03-16, collected from smart meters installed with the customers. The grid data comprises 2 radials of the distribution grid, collected from the network information system of the DSO. The data was anonymized and sim- pliﬁed. The dataset can be used for stochastic load modelling, analysing the grid’s need for ﬂexibility and power ﬂow analy- ses for grid planning purposes.


Specifications
Electrical and Electronic Engineering Specific subject area Active distribution grid planning and analysis Type of data Tables  How the data were  acquired The DSO provided the raw data. Grid data was acquired by combining information from different parts of the network information system (NetBas) and discussing with the DSO. The load data time series were hourly load demands measured from three-phase smart meters of the type OMNIPOWER (from Kamstrup AS, Denmark) installed with the end-users. The Norwegian Meteorological institute provide open access to temperature data from measuring stations on a CC BY 4.0 Licence. Data loading and preprocessing was done through a designated module in a custom-built Python code base, openly available from GitHub [1] Data format Secondary Description of data collection Raw grid and load data from a real industrial distribution grid was obtained from the DSO. The data was anonymized and the grid was simplified to generate a set of secondary data as described in detail in the Experimental design, materials and methods section. Data source location The raw data was collected by the DSO from the Øra industrial area outside Fredrikstad, Norway. The exact location of the grid assets is not given to preserve the anonymity of the grid users.

Value of the Data
• Although many grid models are available online, they are typically test grids that are not representing a real grid. The strength of the grid and load data described in this article is that they describe a real, Norwegian grid with both commercial and industry loads, with hourly load data collected over three years. The load data may represent typical Norwegian electric power usage, where space heating and thus temperature-dependent load makes up a significant amount of the total load. This data is useful for studying a Norwegian distribution system with industrial loads. • The data can be used to analyze historic loads (aggregated or disaggregated), the load data can be used to model future load behavior, analyze the need for power system flexibility, and reliability of supply analysis. The data can also be used to study load patterns for different end users, such as commercial and industrial loads. The data can also be used as inputs to a grid planning case study, for instance using active measures (such as flexible resources) as well as grid investment measures as part of the grid planning. • The data can be used for method development for evaluating remaining capacity in the distribution grid, in normal operation and in outage situations where customers on one radial must be supplied by a backup supply radial [3] .

Objective
The data was initially gathered in the Norwegian research center CINELDI 2 to study load modelling and to develop methodology for analyzing the need for flexibility services in an in- dustrial grid area, which is described in a peer-reviewed conference paper [2] . The dataset is made public to facilitate others who wish to investigate methodology for planning of active distribution grids, or other distribution grid studies [4] . The data may be useful to Norwegian DSOs, the Norwegian transmission system operator (TSO), students or researchers and technology providers/innovators in the electric power distribution industry.

Data Description
The presented data describes a real Norwegian low-to-medium voltage distribution grid. The combined dataset comprises: • A grid dataset that is a selection of the distribution grid pertaining to a substation (HV/MV) 3 in Øra industrial area, more specifically, two radials in this area. • A load dataset measured by smart meters at all the grid customers on the two mentioned radials, containing over three years (2019-03-01 to 2022-03-16) of load data with hourly resolution This data is described in detail in the following subsections. Table 2 gives an overview of the files comprising the grid data. Fig. 1 is an illustration of the grid, including bus names. It is a MV and LV distribution grid comprising two radials of underground cables with a total of 76 buses and 75 branches. The voltage levels in the system are 47, 11, 0.415 and 0.23 kV. See Table 1 for an overview of how many buses are at each voltage level. There is only one load point per bus. One branch (colored red in Fig. 1 ) connects the two radials. The main feeders are located at bus r1v47.0b1 and r2v47.0b1,both at 47 kV. These two buses are the main feeders of their respective radials. Bus r1v11.0b10 and r2v11.0b2 are connected by a branch. This branch is a reserve (backup) connection between the two radials (depending whether it is in service , a term described in the following section).

Technical Specifications in Grid Data
The files described in Table 2 on the MATPOWER format contains various technical specifications. Table 3 shows an excerpt from bus.csv . Below, the different column names are described. The data columns in Table 3 are defined as follows (in accordance with [5] ):      Values in the real and reactive power demand columns (Pd and Qd) are all zero because when the data set is used, it is intended that values from the load demand time series will be used for these variables. As can be seen in Table 3 , the buses have unique names. 4 They are automatically named in the data loading and preprocessing module in the code base [1] . The naming convention, illustrated by Fig. 2 , is meant to give some additional information about the bus.
• "v β", gives the voltage level (in kV) of the bus, such as "v11" for 11 kV • "b γ ", is simply the number of the bus on that voltage level (b1, b2, ..., bN). Table 4 shows an excerpt from branch.csv . Below, the different column names are described. 5 The data columns in Table 4 are defined as follows (in accordance with [5] ): • f_bus: "from" bus number • t_bus: "to" bus number • br_r: resistance (p.u.), set to zero if unknown • br_x: reactance (p.u.), set to zero if unknown • br_b: total line charging susceptance (p.u.), set to zero if unknown • rate_A: MVA rating A (long term rating, set to 10 0 0 if unknown) • rate_B: MVA rating B (short term rating, set to 10 0 0 if unknown) • rate_C: MVA rating C (emergency term rating, set to 10 0 0 if unknown) • tap: transformer off nominal turns ratio, (taps at "from" bus, impedance at "to" bus, i.e. if where Vf and Vt are bus voltages at the from and to bus, respectively) • shift: transformer phase shift angle (degrees), positive → delay • br_status: initial branch status, 1 = in-service, 0 = out-of-service The base value for calculating resistance [R] and reactance [X] per unit is: And the resistance and reactance [ Ω ] is found by multiplying the resistance (p.u.) by the base value:

Load Data
The load data associated with the grid presented in the previous section consist of time series load data with hourly resolution in the period 2019-03-01 to 2022-03-16. The load is measured  Table 6 Excerpt from a file in the load dataset. in kW as an average load per hour. Similarly, it can also be interpreted as the total electric energy used that hour (given in kWh). The data is split among 45 files, named after the 45 buses in the grid with an associated load. See Table 5 for an overview of the files in the load dataset ( Table 6 ).
The load data has been corrected for measuring artifacts due to daylight saving's time. Some of the grid users have connected to the grid during the recorded period, so they do not have load data recorded for the whole three years.

Experimental Design, Materials and Methods
The grid and load data presented here is real data based on raw data from the DSO Norgesnett. Some simplifications were made to the raw data before publishing, and we call the published version the secondary data . Below, the data collection and processing is detailed, first for the grid data, and then for the load data.
Grid data: The secondary grid data presented here was put together through a combination of methods. The raw grid data was exported in .csv-format from NetBas, a GIS-based network information system used by the DSO. The raw grid data was interpreted through discussions with experts at the DSO. The DSO originally provided data describing a larger part of their distribution grid, consisting of several radials connected to the same substation. Two interconnected radials where chosen. The names of the radials, as well as the name of each bus, were anonymized according to the previously described naming convention (see Fig. 2 ).
Load data: The load data was recorded using three-phase smart meters of the type OM-NIPOWER (from Kamstrup AS, Denmark) installed at each grid customer. The data was transferred to the local DSO and stored in their data base. Identifiable load data of the grid users is defined as sensitive information. To maintain anonymity of the grid users, an anonymization procedure was done on the load data. In the raw data, each grid user has a unique number which is attached to each load measurement. The code base [1] has a module which loads and preprocesses the raw data. In this module, raw load data file is first split up into one file for each grid user. Then, the ID number of each grid user is replaced with the anonymous identifier of the bus using the previously described naming convention (see Fig. 2 ). The key file, i.e. where the original identifier is coupled with the anonymous identifier, is only stored on a local machine according to the Data Management Plan agreed to between the DSO and the authors.

Ethics Statements
Identifiable grid-and load data is considered to be sensitive information. However, the dataset has been anonymized as described in the previous section. The publication of the anonymized dataset is done with the DSO's consent, and is detailed in a data management plan between SINTEF Energy Research, the DSO (Norgesnett) and the Norwegian University of Science and Technology (NTNU).

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data Availability
Dataset for a Norwegian medium and low voltage power distribution system with industrial loads (Original data) (Zenodo).