{ "cells": [ { "cell_type": "markdown", "id": "1b91b283", "metadata": {}, "source": [ "(needle_combination)=\n", "# needle_combination\n", "A needle combination or isolated production zone of a generator with separate turbine efficiency curves. Can be used to model pelton turbines and other turbines with forbidden production zones\n", "\n", "| | |\n", "|---|---|\n", "|Input connections|{ref}`generator`, {ref}`needle_comb_reserve_capability`|\n", "|Output connections|{ref}`generator`, {ref}`needle_comb_reserve_capability`|\n", "|License|SHOP_PELTON|\n", "|Release version|13.0.0.a|\n", "\n", "```{contents}\n", ":local:\n", ":depth: 1\n", "```\n", "\n", "## Introduction\n", "The needle_combination object in SHOP is used to model both Pelton turbines and [generators](generator) with forbidden production and/or discharge zones. The SHOP_PELTON license is required to use the needle_combination object. \n", "\n", "## Pelton turbines\n", "When modelling a Pelton unit, the needle_combination represents the production and discharge characteristics of the unit when a specific combination of needles is controlling the flow of water through the nozzle. The attributes [p_min](needle_combination:p_min), [p_max](needle_combination:p_max), [p_nom](needle_combination:p_nom), and [turb_eff_curves](needle_combination:turb_eff_curves) are specified on the needle_combination object to describe its operating range and efficiency. Defining multiple needle_combinations and then connecting them to a generator object will enable SHOP to choose which of the needle_combinations (if any) should be used to generate power in each hour. \n", "\n", "## Turbine with forbidden operating regions\n", "Other turbine types, such as Francis turbines, is usually modelled as having a continuous operating range between [p_min](generator:p_min) and [p_max](generator:p_max) in SHOP. However, some turbines may experience vibration or other unwanted behaviour when discharging water or producing power in a region within its operating range. These forbidden production and/or discharge regions can be modelled by using the needle_combination object. Having needle_combinations without overlap in production and/or discharge ranges will force SHOP to not operate in the forbidden region(s). This is shown in more detail in [this example](pelton).\n", "\n", "## MIP\n", "Running SHOP without binary variables can lead to fractional commitment of generators and production below p_min. This problem can be more pronounced for generators modelled with needle_combinations, since it will be possible to fractionally operate on more than one needle_combination at the same time. The only way to ensure that this problem does not occur is to have an active [mip_flag](plant:mip_flag), which will force the optimization to pick only one needle_combination to operate on. Especially Pelton units delivering [reserves](reserves) may be \"tempted\" to operate a little bit on several needle_combinations to more easily deliver reserve capacity.\n", "\n", "## Input and output\n", "Most of the results for generators modelled with the use of needle_combinations are still found on the generator object, such as [production](generator:production) and [discharge](generator:discharge). A few output attributes are still saved on the needle_combination object, which can be seen in the attribute table below. The same is true for the input attributes: all input generator attributes are still used for Pelton turbines, except for p_min, p_max, p_nom, and turb_eff_curves on the needle_combination object. Some attributes exist on both the generator and needle_combination, such as [p_fcr_min (generator)](generator:p_fcr_min) and [p_fcr_min (needle_combination)](needle_combination:p_fcr_min). In these cases the needle_combination attribute is preferred over the generator attribute, but the generator attribute is still used if it is not present on the needle_combination.\n", "\n", "## Examples\n", " - [](pelton)\n", " \n", "\n", "\n", "\n", "## Attributes" ] }, { "cell_type": "code", "execution_count": 1, "id": "be5db106", "metadata": { "tags": [ "remove-input", "full-width" ] }, "outputs": [ { "data": { "text/html": [ "
\n", "\n" ], "text/plain": [ "" ] }, "execution_count": 1, "metadata": {}, "output_type": "execute_result" } ], "source": [ "from IPython.core.display import HTML\n", "HTML(\"\"\"
\n", "\n", "\"\"\")" ] }, { "cell_type": "markdown", "id": "4330ca48", "metadata": {}, "source": [ "(needle_combination:p_max)=\n", "### p_max\n", "Static maximum production for the needle combination. Unit: MW.\n", "\n", "\n", "(needle_combination:p_min)=\n", "### p_min\n", "Static minimum production for the needle combination. Unit: MW.\n", "\n", "\n", "(needle_combination:p_nom)=\n", "### p_nom\n", "The nominal production that is the rated capacity of the needle combination, only used for droop calculations. Unit: MW.\n", "\n", "\n", "(needle_combination:turb_eff_curves)=\n", "### turb_eff_curves\n", "The turbine efficiency curve(s) as a function of discharge through the turbine for this needle_combination. Several curves can be specified for different head levels (reference value in the XY) to make the efficiency head-dependent. Units: x: M3/S and y: %.\n", "\n", "\n", "(needle_combination:p_fcr_min)=\n", "### p_fcr_min\n", "Temporary minimum production allowed for the needle combination when delivering FCR. If this is not set, any p_fcr_min attribute defined on the generator object will be used instead. Note that the p_fcr_n_min and p_fcr_d_min attributes on the needle_combination will take precedence over this attribute if both are specified. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_fcr_n_min)=\n", "### p_fcr_n_min\n", "Temporary minimum production allowed for the needle combination when delivering FCR-N. If this attribute is not specified, the p_fcr_min attribute on the needle_combination object will be used instead. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_fcr_d_min)=\n", "### p_fcr_d_min\n", "Temporary minimum production allowed for the needle combination when delivering FCR-D. If this attribute is not specified, the p_fcr_min attribute on the needle_combination object will be used instead. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_fcr_max)=\n", "### p_fcr_max\n", "Temporary maximum production allowed for the needle combination when delivering FCR. If this is not set, any p_fcr_max attribute defined on the generator object will be used instead. Note that the p_fcr_n_max and p_fcr_d_max attributes on the needle_combination will take precedence over this attribute if both are specified. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_fcr_n_max)=\n", "### p_fcr_n_max\n", "Temporary maximum production allowed for the needle combination when delivering FCR-N. If this attribute is not specified, the p_fcr_max attribute on the needle_combination object will be used instead. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_fcr_d_max)=\n", "### p_fcr_d_max\n", "Temporary maximum production allowed for the needle combination when delivering FCR-D. If this attribute is not specified, the p_fcr_max attribute on the needle_combination object will be used instead. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_frr_min)=\n", "### p_frr_min\n", "Minimum production allowed for the needle combination when delivering FRR. If not specified, the head-dependent minimum production for the needle combination is used as lower bound for downward FRR. Unit (y): MW.\n", "\n", "\n", "(needle_combination:p_frr_max)=\n", "### p_frr_max\n", "Maximum production allowed for the needle combination when delivering FRR. If not specified, the head-dependent maximum production for the needle combination is used as upper bound for upward FRR. Unit (y): MW.\n", "\n", "\n", "(needle_combination:production_cost)=\n", "### production_cost\n", "Production cost depending on the production of the needle combination. Units: x: MW and y: NOK/MW.\n", "\n", "\n", "(needle_combination:min_discharge)=\n", "### min_discharge\n", "Minimum discharge as a function of net head. Units: x: NO_UNIT and y: NO_UNIT.\n", "\n", "\n", "(needle_combination:max_discharge)=\n", "### max_discharge\n", "Maximum discharge as a function of net head. Units: x: NO_UNIT and y: NO_UNIT.\n", "\n", "\n", "(needle_combination:original_pq_curves)=\n", "### original_pq_curves\n", "Original PQ-curve for the needle combination that includes non-convex regions. Units: x: M3/S and y: MW.\n", "\n", "\n", "(needle_combination:convex_pq_curves)=\n", "### convex_pq_curves\n", "Convexified PQ-curve for the needle combination that includes all the time-dependent operating limits and remove all the nonconcave points of the original PQ curve. The slope of each segment is non-increasing. Units: x: M3/S and y: MW.\n", "\n", "\n", "(needle_combination:final_pq_curves)=\n", "### final_pq_curves\n", "Final PQ curve for the needle combination that is the final form included into the MILP optimization problem. The first point of the convex PQ curve is extended to Q=0. Units: x: M3/S and y: MW.\n", "\n", "\n", "(needle_combination:max_prod)=\n", "### max_prod\n", "The head dependent maximal production of the needle_combination, most accurate in incremental iterations. Unit (y): MW.\n", "\n", "\n", "(needle_combination:min_prod)=\n", "### min_prod\n", "The head dependent minimal production of the needle_combination, most accurate in incremental iterations. Unit (y): MW.\n", "\n", "\n", "(needle_combination:solver_committed_fraction)=\n", "### solver_committed_fraction\n", "The value of the (relaxed) binary variable uesed to model the on/off status of the needle combination in full iterations. The value could be a fractional number between 0 (off) and 1 (on) if the unit commitment constraints are relaxed (mip_flag turned off). Unit (y): NO_UNIT." ] } ], "metadata": { "jupytext": { "text_representation": { "extension": ".md", "format_name": "myst", "format_version": 0.13, "jupytext_version": "1.13.8" } }, "kernelspec": { "display_name": "Python 3", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.13.9" }, "source_map": [ 11, 51, 63 ] }, "nbformat": 4, "nbformat_minor": 5 }