diff --git a/_wiki/adequacy.md b/_wiki/adequacy.md index 5984827d..1808c6b8 100644 --- a/_wiki/adequacy.md +++ b/_wiki/adequacy.md @@ -4,21 +4,29 @@ description: The ability to supply the demand and energy requirements of the end tags: - reliability - nerc -related: [] +related: + - reliability authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.1 date: 2025-03-15 -lastmod: 2025-11-29 -generated: 2025-12-02 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition by NERC -Source: +Source: + +> The ability of the electric system to supply the aggregate electrical demand and energy requirements of the end-use customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements. + + + +> The previous reference is no longer available. +{: .block-danger } -> The ability of the electricity system to supply the aggregate electrical demand and energy requirements of the end-use customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements. + ### Definition in a European Union Regulation diff --git a/_wiki/cascading.md b/_wiki/cascading.md index 6ccfdb62..e535ac64 100644 --- a/_wiki/cascading.md +++ b/_wiki/cascading.md @@ -12,7 +12,7 @@ authors: version: 1.0.0 date: 2025-03-15 lastmod: 2025-06-20 -generated: 2025-12-02 +generated: 2026-01-18 --- ### Definition by NERC @@ -24,6 +24,6 @@ Source: > This version is approved by FERC on 1/21/2016. Another version of the term "Cascading" was approved by FERC on 3/16/2007 and became inactive on 6/30/2016. The term "Cascading Outages" was remanded by FERC on 12/27/2007. -> {: .block-tip } +{: .block-tip } diff --git a/_wiki/dynamic-stability.md b/_wiki/dynamic-stability.md index 9ab52df7..cbe6675b 100644 --- a/_wiki/dynamic-stability.md +++ b/_wiki/dynamic-stability.md @@ -14,13 +14,15 @@ related: - frequency-stability - voltage-stability - rotor-angle-stability + - small-signal-stability + - participation-factor authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.1 +version: 1.0.2 date: 2025-12-02 -lastmod: 2025-12-03 -generated: 2025-12-03 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition by PJM diff --git a/_wiki/frequency-stability.md b/_wiki/frequency-stability.md index 2a7d9fba..3df65876 100644 --- a/_wiki/frequency-stability.md +++ b/_wiki/frequency-stability.md @@ -8,6 +8,7 @@ tags: - article - european-union - europe + - China related: - stability - fast-frequency-response @@ -20,10 +21,10 @@ related: authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.1 +version: 1.0.2 date: 2025-03-15 -lastmod: 2025-11-28 -generated: 2025-12-02 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition in an Article by a Task Force @@ -37,3 +38,13 @@ Source: Source: p6 > 'frequency stability' means the ability of the transmission system to maintain frequency stable in the N-situation and after being subjected to a disturbance; + +### Definition in China grid operation code + +Source: p8 + +> 频率稳定：电力系统受到扰动后，系统频率能够保持或恢复到允许的范围内，不发生频率振荡或崩溃的能力。 + +Translation: + +Frequency Stability: The ability of a power system to maintain or restore system frequency within an allowable range after being subjected to a disturbance, without the occurrence of frequency oscillation or collapse. diff --git a/_wiki/oscillation.md b/_wiki/oscillation.md index 9f36d4e5..f34952c3 100644 --- a/_wiki/oscillation.md +++ b/_wiki/oscillation.md @@ -4,13 +4,16 @@ description: A repetitive motion that can be either undamped, positively damped, tags: - event - oscillation -related: [] +related: + - resonance-stability + - subsynchronous-resonance + - subsynchronous-oscillation authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.1 date: 2025-03-15 -lastmod: 2025-06-18 +lastmod: 2026-01-18 generated: 2025-12-02 --- @@ -27,3 +30,8 @@ Source: > - Inter-area oscillations: From 0.15 to 1 Hz > - Slower dynamics: Such as AGC, less than 0.15 Hz > - Subsynchronous resonance: 10 to 50 Hz (less than synchronous) + + +In the context of power systems, Oscillation is an umbrella term that includes resonance. +{: .block-tip } + diff --git a/_wiki/participation-factors.md b/_wiki/participation-factors.md index 1d049091..7ac7ed79 100644 --- a/_wiki/participation-factors.md +++ b/_wiki/participation-factors.md @@ -4,14 +4,15 @@ description: One definition is about dispath and another is about small-signal s tags: - sensitivity - book -related: [] +related: + - small-signal-stability authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.1 date: 2025-03-15 -lastmod: 2025-06-18 -generated: 2025-12-02 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition by NERC @@ -26,7 +27,9 @@ Source: p716-717, first edition > One problem in using right and left eigenvectors individually for identifying the relationship between the states and the modes is that the elements of the eigenvectors are dependent on units and scaling associated with the state variables. As a solution to this problem, a matrix called the **participation matrix** ($P$), which combines the right and left eigenvectors as follows is proposed in reference 2 as a measure of the association between the state variables and the modes. -More details from the book are excerpted below for reference: +More elaboration can be found in . + +More details from the book are also excerpted below for reference: $$ P = [ P_1 \quad P_2 \quad \dots \quad P_n ] $$ (12.49A) diff --git a/_wiki/reliability.md b/_wiki/reliability.md index 2b9c67f8..9f8bbf70 100644 --- a/_wiki/reliability.md +++ b/_wiki/reliability.md @@ -11,10 +11,10 @@ related: authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.1 date: 2025-03-15 -lastmod: 2025-06-22 -generated: 2025-12-02 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition in an Article by a Joint Task Force of IEEE and CIGRE @@ -29,3 +29,20 @@ Source: Source: > NERC defines the reliability of the interconnected Bulk-Power System in terms of two basic and functional aspects, [adequacy](/wiki/adequacy), and [operating reliability](/wiki/operating-reliability). + +### Definition by NREL + +Source: + +> To frame the issue of reliability, researchers at the National Renewable Energy Laboratory (NREL) use the "three Rs of power system reliability": resource adequacy, operational reliability, and resilience. + +### Definition by FERC + +Source: + +> The grid remains functional even during unanticipated but common system disturbances, such as loss of a source of energy generation from an energy provider or failure of some other system element. When something fails, the grid has to be able to isolate the problem and keep functioning. +> +> Grid reliability is based on two key elements: +> +> 1. Reliable operation – A reliable power grid has the ability to withstand sudden electric system disturbances that can lead to blackouts. +> 2. Resource adequacy - Generally speaking, resource adequacy is the ability of the electric system to meet the energy needs of electricity consumers. This means having sufficient generation to meet projected electric demand. diff --git a/_wiki/security.md b/_wiki/security.md index c8a2b313..75de8d71 100644 --- a/_wiki/security.md +++ b/_wiki/security.md @@ -7,6 +7,7 @@ tags: - ieee-task-force - cigre - article + - China related: - stability - reliability @@ -16,7 +17,7 @@ authors: version: 1.0.0 date: 2025-03-15 lastmod: 2025-06-22 -generated: 2025-12-02 +generated: 2026-01-18 --- ### Definition in an Article by a Joint Task Force of IEEE and CIGRE @@ -25,3 +26,21 @@ Source: > Security of a power system refers to the degree of risk in its ability to survive imminent disturbances (contingencies) without interruption of customer service. > It relates to robustness of the system to imminent disturbances and, hence, depends on the system operating condition as well as the contingent probability of disturbances. + +### Definition in China grid operation code + +Source: p8 + +> 电力系统安全性：电力系统在运行中承受扰动（例如突然失去电力系统的元件，较大功率波动或短路故障等）的能力。 通过两个特性表征： +> +> a) 电力系统能承受住扰动引起的暂态过程并过渡到一个可接受的运行工况； +> +> b) 在新的运行工况下，各种约束条件得到满足。 + +Translation: + +Power System Security: The ability of a power system to withstand disturbances during operation (such as the sudden loss of system components, significant power fluctuations, or short-circuit faults). It is characterized by two specific attributes: + +a) The power system can withstand the transient processes caused by the disturbance and transition to an acceptable operating state; + +b) Under the new operating state, various constraints are satisfied. diff --git a/_wiki/small-signal-stability.md b/_wiki/small-signal-stability.md index a5632f85..5291e4ed 100644 --- a/_wiki/small-signal-stability.md +++ b/_wiki/small-signal-stability.md @@ -4,14 +4,16 @@ description: The ability to maintain synchronism when subjected to small disturb tags: - stability - book -related: [] +related: + - dynamic-stability + - participation-factor authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.1 date: 2025-03-15 -lastmod: 2025-06-19 -generated: 2025-12-02 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition in a Textbook diff --git a/_wiki/subsynchronous-oscillation.md b/_wiki/subsynchronous-oscillation.md new file mode 100644 index 00000000..63f22ec7 --- /dev/null +++ b/_wiki/subsynchronous-oscillation.md @@ -0,0 +1,22 @@ +--- +title: Subsynchronous Oscillation +description: SSO. +tags: + - stability +related: + - oscillation + - subsynchronous-resonance +authors: + - name: Jinning Wang + url: https://jinningwang.github.io +version: 1.0.0 +date: 2026-01-18 +lastmod: 2026-01-18 +generated: 2026-01-18 +--- + +### Defintion in an Article + +Source: + +> Subsynchronous oscillation is an electric power system condition where the electric network exchanges significant energy with a turbine-generator at one or more of the natural frequencies of the combined system below the synchronous frequency of the system following a disturbance from equilibrium. The above excludes the rigid body modes of the turbine-generator rotors. diff --git a/_wiki/subsynchronous-resonance.md b/_wiki/subsynchronous-resonance.md index 8763d98b..a9b3b968 100644 --- a/_wiki/subsynchronous-resonance.md +++ b/_wiki/subsynchronous-resonance.md @@ -3,13 +3,15 @@ title: Subsynchronous Resonance description: SSR. A condition involving energy exchange at natural frequencies below the synchronous frequency. tags: - stability -related: [] +related: + - oscillation + - subsynchronous-oscillation authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.1 date: 2025-03-15 -lastmod: 2025-06-20 +lastmod: 2026-01-18 generated: 2025-12-02 --- diff --git a/_wiki/voltage-stability.md b/_wiki/voltage-stability.md index 829072e3..29471166 100644 --- a/_wiki/voltage-stability.md +++ b/_wiki/voltage-stability.md @@ -8,6 +8,7 @@ tags: - article - european-union - europe + - China related: - stability - frequency-stability @@ -16,10 +17,10 @@ related: authors: - name: Jinning Wang url: https://jinningwang.github.io -version: 1.0.0 +version: 1.0.2 date: 2025-03-15 -lastmod: 2025-06-20 -generated: 2025-12-02 +lastmod: 2026-01-18 +generated: 2026-01-18 --- ### Definition in an Article by a Task Force @@ -28,8 +29,22 @@ Source: > Voltage stability refers to the ability of a power system to maintain steady voltages close to nominal value at all buses in the system after being subjected to a disturbance. +> Short-term voltage stability involves dynamics of fast acting load components such as induction motors, electronically controlled loads, HVDC links and inverter-based generators. The study period of interest is in the order of several seconds, similar to rotor angle stability or converter-driven stability (slow interaction type). Accordingly, models with the same degree of detail as for the above stability classes must be used. In addition, for short-term voltage stability, the dynamic modeling of loads is essential, and short circuit faults near loads are the main concern. + +> Long-term voltage stability involves slower acting equipment such as tap-changing transformers, thermostatically controlled loads, and generator current limiters. It usually occurs in the form of a progressive reduction of voltages at some network buses. The maximum power transfer and voltage support are further limited when some of the generators hit their field and/or armature current time-overload capability limits. The study period of interest may extend to several minutes, and long-term simulations are required for analysis of system dynamic performance. + ### Definition in a European Union Regulation Source: p6 > 'voltage stability' means the ability of a transmission system to maintain acceptable voltages at all nodes in the transmission system in the N-situation and after being subjected to a disturbance; + +### Definition in China grid operation code + +Source: p8 + +> 电压稳定：电力系统受到扰动后，系统电压能够保持或恢复到允许的范围内，不发生电压崩溃的能力。 + +Translation: + +Voltage Stability: The ability of a power system to maintain or restore system voltage within an allowable range after being subjected to a disturbance, without the occurrence of voltage collapse. diff --git a/assets/bibliography/papers.bib b/assets/bibliography/papers.bib index 0b6ecc7b..5438c676 100644 --- a/assets/bibliography/papers.bib +++ b/assets/bibliography/papers.bib @@ -2159,3 +2159,55 @@ @article{schweppe1970staticstate interative technique for calculating the state estimate, and concepts underlying the detection and identification of modeling errors. Problems of interconnected systems are considered. Results of some initial computer simulation tests are discussed.}, } + +@online{geocaris2022assessing, + abbr = {Industry}, + author = {Madeline Geocaris}, + title = {Assessing Power System Reliability in a Changing Grid Environment}, + month = {August}, + year = {2022}, + bibtex_show = {true}, + url = {https://www.nrel.gov/news/detail/program/2022/assessing-power-system-reliability-in-a-changing-grid-environment}, +} + +@online{ferc2023reliability, + abbr = {Industry}, + title = {Reliability}, + url = {https://www.ferc.gov/reliability-explainer}, + day = {16}, + year = {2023}, + month = {August}, + bibtex_show = {true}, +} + +@online{gbt2022, + abbr = {Industry}, + title = {GB/T 31464-2022: The Grid Operation Code}, + author = {SAMR and SAC}, + url = {https://openstd.samr.gov.cn/bzgk/std/newGbInfo?hcno=2E138E6A6D540124290DBBA47FFA1E14}, + year = {2022}, + day = {30}, + month = {12}, + bibtex_show = {true}, + language = {Chinese}, +} + +@online{sun2021smallsignal, + abbr = {Book}, + author = {Kai Sun}, + title = {ECE 522 - Power Systems Analysis II: Small-Signal Stability}, + year = {2021}, + url = {https://web.eecs.utk.edu/~kaisun/ECE522/ECE522_7-Small-signalStability.pdf}, + pdf = {https://web.eecs.utk.edu/~kaisun/ECE522/ECE522_7-Small-signalStability.pdf}, + bibtex_show = {true}, +} + +@article{ieee1985terms, + journal={IEEE Transactions on Power Apparatus and Systems}, + title={Terms, Definitions and Symbols for Subsynchronous Oscillations}, + year={1985}, + volume={PAS-104}, + number={6}, + pages={1326-1334}, + doi={10.1109/TPAS.1985.319152}, +} diff --git a/database/build/index.json b/database/build/index.json index c44d7b60..0f54051a 100644 --- a/database/build/index.json +++ b/database/build/index.json @@ -19,7 +19,7 @@ "reliability", "nerc" ], - "updated_at": "2025-11-29" + "updated_at": "2026-01-18" }, { "id": "ambient-adjusted-ratings", @@ -511,7 +511,7 @@ "european-union", "europe" ], - "updated_at": "2025-12-03" + "updated_at": "2026-01-18" }, { "id": "dynamic-study-model", @@ -805,9 +805,10 @@ "ieee-task-force", "article", "european-union", - "europe" + "europe", + "China" ], - "updated_at": "2025-11-28" + "updated_at": "2026-01-18" }, { "id": "futures-market", @@ -1204,7 +1205,7 @@ "sensitivity", "book" ], - "updated_at": "2025-06-18" + "updated_at": "2026-01-18" }, { "id": "performance-based-metrics", @@ -1353,7 +1354,7 @@ "operation", "article" ], - "updated_at": "2025-06-22" + "updated_at": "2026-01-18" }, { "id": "remedial-action-scheme", @@ -1538,7 +1539,8 @@ "ieee", "ieee-task-force", "cigre", - "article" + "article", + "China" ], "updated_at": "2025-06-22" }, @@ -1580,7 +1582,7 @@ "stability", "book" ], - "updated_at": "2025-06-19" + "updated_at": "2026-01-18" }, { "id": "smart-grid", @@ -1683,6 +1685,15 @@ ], "updated_at": "2025-06-20" }, + { + "id": "subsynchronous-oscillation", + "title": "Subsynchronous Oscillation", + "summary": "SSO.", + "tags": [ + "stability" + ], + "updated_at": "2026-01-18" + }, { "id": "subsynchronous-resonance", "title": "Subsynchronous Resonance", @@ -1925,9 +1936,10 @@ "ieee-task-force", "article", "european-union", - "europe" + "europe", + "China" ], - "updated_at": "2025-06-20" + "updated_at": "2026-01-18" }, { "id": "waveform-measurement-unit", @@ -1981,5 +1993,5 @@ "updated_at": "2025-11-02" } ], - "generated_at": "2025-12-04" + "generated_at": "2026-01-18" } diff --git a/database/build/tags.json b/database/build/tags.json index cf564855..9ea3795f 100644 --- a/database/build/tags.json +++ b/database/build/tags.json @@ -13,11 +13,11 @@ "count": 29 }, { - "tag": "ieee", - "count": 25 + "tag": "stability", + "count": 26 }, { - "tag": "stability", + "tag": "ieee", "count": 25 }, { @@ -120,6 +120,10 @@ "tag": "standard", "count": 4 }, + { + "tag": "China", + "count": 3 + }, { "tag": "artificial-intelligence", "count": 3 diff --git a/database/json/adequacy.json b/database/json/adequacy.json index 344b58d2..bdaa9fa1 100644 --- a/database/json/adequacy.json +++ b/database/json/adequacy.json @@ -8,12 +8,14 @@ "reliability", "nerc" ], - "related": [], - "version": "1.0.0", + "related": [ + "reliability" + ], + "version": "1.0.1", "breaking": false, "dates": { "created": "2025-03-15", - "last_modified": "2025-11-29" + "last_modified": "2026-01-18" }, "authors": [ { @@ -29,10 +31,10 @@ "title": "Definition by NERC", "type": "definition", "source_keys": [ - "nerc2013terminology" + "nerc2024glossary" ], "page": null, - "body_md": "> The ability of the electricity system to supply the aggregate electrical demand and energy requirements of the end-use customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements.\n" + "body_md": "> The ability of the electric system to supply the aggregate electrical demand and energy requirements of the end-use customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements.\n\n\n\n> The previous reference is no longer available.\n{: .block-danger }\n\n\n" }, { "order": 2, diff --git a/database/json/cascading.json b/database/json/cascading.json index 3e223c87..79b277b8 100644 --- a/database/json/cascading.json +++ b/database/json/cascading.json @@ -34,7 +34,7 @@ "nerc2024glossary" ], "page": null, - "body_md": "> The uncontrolled **successive loss** of System Elements triggered by an incident at any location. Cascading results in widespread electric service interruption that cannot be restrained from sequentially spreading beyond an area predetermined by studies.\n\n\n\n> This version is approved by FERC on 1/21/2016. Another version of the term \"Cascading\" was approved by FERC on 3/16/2007 and became inactive on 6/30/2016. The term \"Cascading Outages\" was remanded by FERC on 12/27/2007.\n> {: .block-tip }\n\n\n" + "body_md": "> The uncontrolled **successive loss** of System Elements triggered by an incident at any location. Cascading results in widespread electric service interruption that cannot be restrained from sequentially spreading beyond an area predetermined by studies.\n\n\n\n> This version is approved by FERC on 1/21/2016. Another version of the term \"Cascading\" was approved by FERC on 3/16/2007 and became inactive on 6/30/2016. The term \"Cascading Outages\" was remanded by FERC on 12/27/2007.\n{: .block-tip }\n\n\n" } ] } diff --git a/database/json/dynamic-stability.json b/database/json/dynamic-stability.json index f31a5b37..2f0da165 100644 --- a/database/json/dynamic-stability.json +++ b/database/json/dynamic-stability.json @@ -17,13 +17,15 @@ "transient-stability", "frequency-stability", "voltage-stability", - "rotor-angle-stability" + "rotor-angle-stability", + "small-signal-stability", + "participation-factor" ], - "version": "1.0.1", + "version": "1.0.2", "breaking": false, "dates": { "created": "2025-12-02", - "last_modified": "2025-12-03" + "last_modified": "2026-01-18" }, "authors": [ { diff --git a/database/json/frequency-stability.json b/database/json/frequency-stability.json index a57f9ce4..53eb2a4e 100644 --- a/database/json/frequency-stability.json +++ b/database/json/frequency-stability.json @@ -10,7 +10,8 @@ "ieee-task-force", "article", "european-union", - "europe" + "europe", + "China" ], "related": [ "stability", @@ -22,11 +23,11 @@ "automatic-generation-control", "n-situation" ], - "version": "1.0.1", + "version": "1.0.2", "breaking": false, "dates": { "created": "2025-03-15", - "last_modified": "2025-11-28" + "last_modified": "2026-01-18" }, "authors": [ { @@ -57,6 +58,17 @@ ], "page": "p6", "body_md": "> 'frequency stability' means the ability of the transmission system to maintain frequency stable in the N-situation and after being subjected to a disturbance;\n" + }, + { + "order": 3, + "id": "definition-in-china-grid-operation-code", + "title": "Definition in China grid operation code", + "type": "definition", + "source_keys": [ + "gbt2022" + ], + "page": "p8", + "body_md": "> 频率稳定：电力系统受到扰动后，系统频率能够保持或恢复到允许的范围内，不发生频率振荡或崩溃的能力。\n\nTranslation:\n\nFrequency Stability: The ability of a power system to maintain or restore system frequency within an allowable range after being subjected to a disturbance, without the occurrence of frequency oscillation or collapse.\n" } ] } diff --git a/database/json/participation-factors.json b/database/json/participation-factors.json index 6a19805e..31fe1e4f 100644 --- a/database/json/participation-factors.json +++ b/database/json/participation-factors.json @@ -8,12 +8,14 @@ "sensitivity", "book" ], - "related": [], - "version": "1.0.0", + "related": [ + "small-signal-stability" + ], + "version": "1.0.1", "breaking": false, "dates": { "created": "2025-03-15", - "last_modified": "2025-06-18" + "last_modified": "2026-01-18" }, "authors": [ { @@ -43,7 +45,7 @@ "kundur1994Power" ], "page": "p716-717, first edition", - "body_md": "> One problem in using right and left eigenvectors individually for identifying the relationship between the states and the modes is that the elements of the eigenvectors are dependent on units and scaling associated with the state variables. As a solution to this problem, a matrix called the **participation matrix** ($P$), which combines the right and left eigenvectors as follows is proposed in reference 2 as a measure of the association between the state variables and the modes.\n\nMore details from the book are excerpted below for reference:\n\n$$ P = [ P_1 \\quad P_2 \\quad \\dots \\quad P_n ] $$ (12.49A)\n\nwith\n\n$$\nP_i =\n\\begin{bmatrix}\np_{1i} \\\\\np_{2i} \\\\\n\\vdots \\\\\np_{ni}\n\\end{bmatrix}\n=\n\\begin{bmatrix}\n\\phi_{1i} \\psi_{i1} \\\\\n\\phi_{2i} \\psi_{i2} \\\\\n\\vdots \\\\\n\\phi_{ni} \\psi_{in}\n\\end{bmatrix}\n$$ (12.49B)\n\nwhere\n\n$\\phi_{ki}$ = the element on the $k$th row and $i$th column of the modal matrix $\\Phi$\n
= $k$th entry of the right eigenvector $\\Phi_i$\n\n$\\psi_{ik}$ = the element on the $i$th row and $k$th column of the modal matrix $\\Psi$\n
= $k$th entry of the left eigenvector $\\Psi_i$\n\nThe element $p_{ki} = \\phi_{ki} \\psi_{ik}$ is termed the **participation factor**.\nIt is a measure of the relative participation of the $k$th state variable in the $i$th mode, and vice versa.\n\nSince $\\phi_{ki}$ measures the **activity** of $x_k$ in the $i$th mode and $\\psi_{ik}$ weighs the contribution of this activity to the mode, the product $p_{ki}$ measures the **net participation**.\nThe effect of multiplying the elements of the left and right eigenvectors is also to make $p_{ki}$ dimensionless (i.e., independent of the choice of units).\n\nIn view of the eigenvector normalization, the sum of the participation factors associated with any mode $\\sum_{i=1}^{n} p_{ki}$ or with any state variable $\\sum_{k=1}^{n} p_{ki}$ is equal to 1.\n\nFrom Equation 12.48, we see that the participation factor $p_{ki}$ is actually equal to the sensitivity of the eigenvalue $\\lambda_i$ to the diagonal element $a_{kk}$ of the state matrix $A$:\n\n$$ p_{ki} = \\frac{\\partial \\lambda_i}{\\partial a_{kk}} $$ (12.50)\n\nAs we will see in a number of examples in this chapter, the **participation factors are generally indicative of the relative participations** of the respective states in the corresponding modes.\n$$\n" + "body_md": "> One problem in using right and left eigenvectors individually for identifying the relationship between the states and the modes is that the elements of the eigenvectors are dependent on units and scaling associated with the state variables. As a solution to this problem, a matrix called the **participation matrix** ($P$), which combines the right and left eigenvectors as follows is proposed in reference 2 as a measure of the association between the state variables and the modes.\n\nMore elaboration can be found in .\n\nMore details from the book are also excerpted below for reference:\n\n$$ P = [ P_1 \\quad P_2 \\quad \\dots \\quad P_n ] $$ (12.49A)\n\nwith\n\n$$\nP_i =\n\\begin{bmatrix}\np_{1i} \\\\\np_{2i} \\\\\n\\vdots \\\\\np_{ni}\n\\end{bmatrix}\n=\n\\begin{bmatrix}\n\\phi_{1i} \\psi_{i1} \\\\\n\\phi_{2i} \\psi_{i2} \\\\\n\\vdots \\\\\n\\phi_{ni} \\psi_{in}\n\\end{bmatrix}\n$$ (12.49B)\n\nwhere\n\n$\\phi_{ki}$ = the element on the $k$th row and $i$th column of the modal matrix $\\Phi$\n
= $k$th entry of the right eigenvector $\\Phi_i$\n\n$\\psi_{ik}$ = the element on the $i$th row and $k$th column of the modal matrix $\\Psi$\n
= $k$th entry of the left eigenvector $\\Psi_i$\n\nThe element $p_{ki} = \\phi_{ki} \\psi_{ik}$ is termed the **participation factor**.\nIt is a measure of the relative participation of the $k$th state variable in the $i$th mode, and vice versa.\n\nSince $\\phi_{ki}$ measures the **activity** of $x_k$ in the $i$th mode and $\\psi_{ik}$ weighs the contribution of this activity to the mode, the product $p_{ki}$ measures the **net participation**.\nThe effect of multiplying the elements of the left and right eigenvectors is also to make $p_{ki}$ dimensionless (i.e., independent of the choice of units).\n\nIn view of the eigenvector normalization, the sum of the participation factors associated with any mode $\\sum_{i=1}^{n} p_{ki}$ or with any state variable $\\sum_{k=1}^{n} p_{ki}$ is equal to 1.\n\nFrom Equation 12.48, we see that the participation factor $p_{ki}$ is actually equal to the sensitivity of the eigenvalue $\\lambda_i$ to the diagonal element $a_{kk}$ of the state matrix $A$:\n\n$$ p_{ki} = \\frac{\\partial \\lambda_i}{\\partial a_{kk}} $$ (12.50)\n\nAs we will see in a number of examples in this chapter, the **participation factors are generally indicative of the relative participations** of the respective states in the corresponding modes.\n$$\n" } ] } diff --git a/database/json/reliability.json b/database/json/reliability.json index 71555a7e..a2b199fd 100644 --- a/database/json/reliability.json +++ b/database/json/reliability.json @@ -13,11 +13,11 @@ "stability", "security" ], - "version": "1.0.0", + "version": "1.0.1", "breaking": false, "dates": { "created": "2025-03-15", - "last_modified": "2025-06-22" + "last_modified": "2026-01-18" }, "authors": [ { @@ -48,6 +48,28 @@ ], "page": null, "body_md": "> NERC defines the reliability of the interconnected Bulk-Power System in terms of two basic and functional aspects, [adequacy](/wiki/adequacy), and [operating reliability](/wiki/operating-reliability).\n" + }, + { + "order": 3, + "id": "definition-by-nrel", + "title": "Definition by NREL", + "type": "definition", + "source_keys": [ + "geocaris2022assessing" + ], + "page": null, + "body_md": "> To frame the issue of reliability, researchers at the National Renewable Energy Laboratory (NREL) use the \"three Rs of power system reliability\": resource adequacy, operational reliability, and resilience.\n" + }, + { + "order": 4, + "id": "definition-by-ferc", + "title": "Definition by FERC", + "type": "definition", + "source_keys": [ + "ferc2023reliability" + ], + "page": null, + "body_md": "> The grid remains functional even during unanticipated but common system disturbances, such as loss of a source of energy generation from an energy provider or failure of some other system element. When something fails, the grid has to be able to isolate the problem and keep functioning.\n>\n> Grid reliability is based on two key elements:\n>\n> 1. Reliable operation – A reliable power grid has the ability to withstand sudden electric system disturbances that can lead to blackouts.\n> 2. Resource adequacy - Generally speaking, resource adequacy is the ability of the electric system to meet the energy needs of electricity consumers. This means having sufficient generation to meet projected electric demand.\n" } ] } diff --git a/database/json/security.json b/database/json/security.json index 7fda14de..78fdee3d 100644 --- a/database/json/security.json +++ b/database/json/security.json @@ -9,7 +9,8 @@ "ieee", "ieee-task-force", "cigre", - "article" + "article", + "China" ], "related": [ "stability", @@ -39,6 +40,17 @@ ], "page": null, "body_md": "> Security of a power system refers to the degree of risk in its ability to survive imminent disturbances (contingencies) without interruption of customer service.\n> It relates to robustness of the system to imminent disturbances and, hence, depends on the system operating condition as well as the contingent probability of disturbances.\n" + }, + { + "order": 2, + "id": "definition-in-china-grid-operation-code", + "title": "Definition in China grid operation code", + "type": "definition", + "source_keys": [ + "gbt2022" + ], + "page": "p8", + "body_md": "> 电力系统安全性：电力系统在运行中承受扰动（例如突然失去电力系统的元件，较大功率波动或短路故障等）的能力。 通过两个特性表征：\n>\n> a) 电力系统能承受住扰动引起的暂态过程并过渡到一个可接受的运行工况；\n>\n> b) 在新的运行工况下，各种约束条件得到满足。\n\nTranslation:\n\nPower System Security: The ability of a power system to withstand disturbances during operation (such as the sudden loss of system components, significant power fluctuations, or short-circuit faults). It is characterized by two specific attributes: \n\na) The power system can withstand the transient processes caused by the disturbance and transition to an acceptable operating state;\n\nb) Under the new operating state, various constraints are satisfied.\n" } ] } diff --git a/database/json/small-signal-stability.json b/database/json/small-signal-stability.json index a78ecd76..375b286a 100644 --- a/database/json/small-signal-stability.json +++ b/database/json/small-signal-stability.json @@ -8,12 +8,15 @@ "stability", "book" ], - "related": [], - "version": "1.0.0", + "related": [ + "dynamic-stability", + "participation-factor" + ], + "version": "1.0.1", "breaking": false, "dates": { "created": "2025-03-15", - "last_modified": "2025-06-19" + "last_modified": "2026-01-18" }, "authors": [ { diff --git a/database/json/subsynchronous-oscillation.json b/database/json/subsynchronous-oscillation.json new file mode 100644 index 00000000..a652eacd --- /dev/null +++ b/database/json/subsynchronous-oscillation.json @@ -0,0 +1,41 @@ +{ + "$schema": "https://ps-wiki.github.io/schema/v1/term.schema.json", + "id": "subsynchronous-oscillation", + "title": "Subsynchronous Oscillation", + "description": "SSO.", + "language": "en", + "tags": [ + "stability" + ], + "related": [ + "oscillation", + "subsynchronous-resonance" + ], + "version": "1.0.0", + "breaking": false, + "dates": { + "created": "2026-01-18", + "last_modified": "2026-01-18" + }, + "authors": [ + { + "name": "Jinning Wang", + "url": "https://jinningwang.github.io" + } + ], + "content": { + "sections": [ + { + "order": 1, + "id": "defintion-in-an-article", + "title": "Defintion in an Article", + "type": "definition", + "source_keys": [ + "ieee1985terms" + ], + "page": null, + "body_md": "> Subsynchronous oscillation is an electric power system condition where the electric network exchanges significant energy with a turbine-generator at one or more of the natural frequencies of the combined system below the synchronous frequency of the system following a disturbance from equilibrium. The above excludes the rigid body modes of the turbine-generator rotors.\n" + } + ] + } +} diff --git a/database/json/voltage-stability.json b/database/json/voltage-stability.json index edd27d13..f279e37a 100644 --- a/database/json/voltage-stability.json +++ b/database/json/voltage-stability.json @@ -10,7 +10,8 @@ "ieee-task-force", "article", "european-union", - "europe" + "europe", + "China" ], "related": [ "stability", @@ -18,11 +19,11 @@ "rotor-angle-stability", "n-situation" ], - "version": "1.0.0", + "version": "1.0.2", "breaking": false, "dates": { "created": "2025-03-15", - "last_modified": "2025-06-20" + "last_modified": "2026-01-18" }, "authors": [ { @@ -41,7 +42,7 @@ "hatziargyriou2021stability" ], "page": null, - "body_md": "> Voltage stability refers to the ability of a power system to maintain steady voltages close to nominal value at all buses in the system after being subjected to a disturbance.\n" + "body_md": "> Voltage stability refers to the ability of a power system to maintain steady voltages close to nominal value at all buses in the system after being subjected to a disturbance.\n\n> Short-term voltage stability involves dynamics of fast acting load components such as induction motors, electronically controlled loads, HVDC links and inverter-based generators. The study period of interest is in the order of several seconds, similar to rotor angle stability or converter-driven stability (slow interaction type). Accordingly, models with the same degree of detail as for the above stability classes must be used. In addition, for short-term voltage stability, the dynamic modeling of loads is essential, and short circuit faults near loads are the main concern.\n\n> Long-term voltage stability involves slower acting equipment such as tap-changing transformers, thermostatically controlled loads, and generator current limiters. It usually occurs in the form of a progressive reduction of voltages at some network buses. The maximum power transfer and voltage support are further limited when some of the generators hit their field and/or armature current time-overload capability limits. The study period of interest may extend to several minutes, and long-term simulations are required for analysis of system dynamic performance.\n" }, { "order": 2, @@ -53,6 +54,17 @@ ], "page": "p6", "body_md": "> 'voltage stability' means the ability of a transmission system to maintain acceptable voltages at all nodes in the transmission system in the N-situation and after being subjected to a disturbance;\n" + }, + { + "order": 3, + "id": "definition-in-china-grid-operation-code", + "title": "Definition in China grid operation code", + "type": "definition", + "source_keys": [ + "gbt2022" + ], + "page": "p8", + "body_md": "> 电压稳定：电力系统受到扰动后，系统电压能够保持或恢复到允许的范围内，不发生电压崩溃的能力。\n\nTranslation:\n\nVoltage Stability: The ability of a power system to maintain or restore system voltage within an allowable range after being subjected to a disturbance, without the occurrence of voltage collapse.\n" } ] }