outage_table: Convolve generators to create outage tables

In NREL/repra: Renewable Energy Probability Resource Assessment Tool (REPRA)

Description

Allows to create outage tables for different areas and levels of aggregation for a list of capacities and equivalent forced outage rates (EFOR) for generators. The assumption is that the generator outages are independent from each other. The table can be used to quickly compute loss-of-load probability (LOLP) and expected unserved energy (EUE).

Usage

outage_table(generators, levels = NULL, threshold = 1e-06, round = 1)

Arguments

generators	Data frame with the list of generators (see details for requirements)
levels	Optional data frame that contains levels of aggregation, e.g., BAA, transmission area or interconnection (see details for requirements)
threshold	Table entries with LOLP below this value are ignored
round	Used to round capacities (default is 1 MW)

Details

Requirements for generators:

• The data frame must contain two columns: Capacity and EFOR (Other columns will be ignored)

• Optionally if a column called Area exists, it will be used to create separate tables within each area

Requirements for levels:

• This parameter is optional

• If levels is provided, generators must contain a column called Area

• The first column must contain the most granular level of data and compatible with columns Area in generators

• The column names in levels will become the names of the different levels of aggregation

Value

The result is a data.table object that is used to calculate LOLP metrics. For each area, the output presents the following columns: Capacity, Prob, LOLP and BaseEUE. The column Capacity is duplicated as (Capacity2) and is used internally by the LOLP calculation functions.

Given a load level L, the probability parameters are calculated as follows:

• Choose the first row with L <= Capacity

• The loss-of-load probability is the value in the LOLP for that row

• Expected unserved energy can be quickly calculated as EUE = BaseEUE + (L - Capacity) * LOLP. This is equivalent to calculating the sum of (L - Capacity) * Prob for all rows with L < Capacity

References

R. Billinton, and R. N. Allan, Reliability evaluation of power systems, New York: Plenum Press 1996.

See Also

format_timedata is the function that creates compatible time data objects

Examples

# Outage table with one 10-MW generator with 2% EFOR
outage_table(data.frame(Capacity = 10, EFOR = 0.02))

# Outage table with two generators (10 MW with 2% EFOR and 20 MW with 1% EFOR)
outage_table(data.frame(Capacity = c(10, 20), EFOR = c(0.02, 0.01)))

# List of generators and areas
gens <- data.frame(Area = c(rep("A", 10), rep("B", 5)),
                   Capacity = rep(60, 15),
                   EFOR = rep(0.08, 15))
levs <- data.frame(BAA = c("A", "B"), Region = c("All", "All"))

# Create a single outage table (without specifying area)
outage_table(gens[, c("Capacity", "EFOR")])

# Create an outage table for each 'Area'
outage_table(gens)

# Create table for each 'Area' and different and levels of aggregation in 'levs'
outage_table(gens, levs)

NREL/repra documentation built on May 7, 2019, 6:03 p.m.