Power Module

The power module contains a set of functions to calculate quantities of interest for power production and power quality.

Characteristics

The characteristics submodule calculates power quantities of interest from voltage and current timseries.

instantaneous_frequency

Calculates instantaneous frequency of measured voltage

dc_power

Calculates DC power from voltage and current

ac_power_three_phase

Calculates magnitude of active AC power from line to neutral voltage and current
mhkit.power.characteristics.instantaneous_frequency(um)[source]

Calculates instantaneous frequency of measured voltage

Parameters

um (pandas Series or DataFrame) – Measured voltage (V) indexed by time

Returns

frequency (pandas DataFrame) – Frequency of the measured voltage (Hz) indexed by time with signal name columns

mhkit.power.characteristics.dc_power(voltage, current)[source]

Calculates DC power from voltage and current

Parameters

  • voltage (pandas Series or DataFrame) – Measured DC voltage [V] indexed by time

  • current (pandas Series or DataFrame) – Measured three phase current [A] indexed by time

Returns

P (pandas DataFrame) – DC power [W] from each channel and gross power indexed by time

mhkit.power.characteristics.ac_power_three_phase(voltage, current, power_factor, line_to_line=False)[source]

Calculates magnitude of active AC power from line to neutral voltage and current

Parameters

  • voltage (pandas DataFrame) – Time-series of three phase measured voltage [V] indexed by time

  • current (pandas DataFrame) – Time-series of three phase measured current [A] indexed by time

  • power_factor (float) – Power factor for the efficiency of the system

  • line_to_line (bool) – Set to true if the given voltage measurements are line_to_line

Returns

P (pandas DataFrame) – Magnitude of active AC power [W] indexed by time with Power column

Quality

The quality submodule functions assess power quality, including harmonics, interharmonics, and distortion. Calculations are based on IEC TS 62600-30:2018 ED1 and IEC TS 61000-4-7:2008 ED2.

harmonics

Calculates the harmonics from time series of voltage or current based on IEC 61000-4-7.

harmonic_subgroups

Calculates the harmonic subgroups based on IEC 61000-4-7

total_harmonic_current_distortion

Calculates the total harmonic current distortion (THC) based on IEC/TS 62600-30

interharmonics

Calculates the interharmonics from the harmonics of current
mhkit.power.quality.harmonics(x, freq, grid_freq)[source]

Calculates the harmonics from time series of voltage or current based on IEC 61000-4-7.

Parameters

  • x (pandas Series or DataFrame) – Time-series of voltage [V] or current [A]

  • freq (float or Int) – Frequency of the time-series data [Hz]

  • grid_freq (int) – Value indicating if the power supply is 50 or 60 Hz. Options = 50 or 60

Returns

harmonics (pandas DataFrame) – Amplitude of the time-series data harmonics indexed by the harmonic frequency with signal name columns

mhkit.power.quality.harmonic_subgroups(harmonics, grid_freq)[source]

Calculates the harmonic subgroups based on IEC 61000-4-7

Parameters

  • harmonics (pandas Series or DataFrame) – Harmonic amplitude indexed by the harmonic frequency

  • grid_freq (int) – Value indicating if the power supply is 50 or 60 Hz. Options = 50 or 60

Returns

harmonic_subgroups (pandas DataFrame) – Harmonic subgroups indexed by harmonic frequency with signal name columns

mhkit.power.quality.total_harmonic_current_distortion(harmonics_subgroup, rated_current)[source]

Calculates the total harmonic current distortion (THC) based on IEC/TS 62600-30

Parameters

  • harmonics_subgroup (pandas DataFrame or Series) – Subgrouped current harmonics indexed by harmonic frequency

  • rated_current (float) – Rated current of the energy device in Amps

Returns

THCD (pd.DataFrame) – Total harmonic current distortion indexed by signal name with THCD column

mhkit.power.quality.interharmonics(harmonics, grid_freq)[source]

Calculates the interharmonics from the harmonics of current

Parameters

  • harmonics (pandas Series or DataFrame) – Harmonic amplitude indexed by the harmonic frequency

  • grid_freq (int) – Value indicating if the power supply is 50 or 60 Hz. Options = 50 or 60

Returns

interharmonics (pandas DataFrame) – Interharmonics groups