CN104124715A - Automatic gain scheduling method for wind power plants distributed as priority level according to blower involvement - Google Patents
Automatic gain scheduling method for wind power plants distributed as priority level according to blower involvement Download PDFInfo
- Publication number
- CN104124715A CN104124715A CN201410390674.7A CN201410390674A CN104124715A CN 104124715 A CN104124715 A CN 104124715A CN 201410390674 A CN201410390674 A CN 201410390674A CN 104124715 A CN104124715 A CN 104124715A
- Authority
- CN
- China
- Prior art keywords
- level
- fan
- active
- benchmark
- power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000010248 power generation Methods 0.000 claims abstract description 11
- 239000003550 marker Substances 0.000 claims abstract description 6
- 230000005611 electricity Effects 0.000 claims description 10
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000000630 rising effect Effects 0.000 description 2
- 241000124001 Alcyonacea Species 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000001932 seasonal effect Effects 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
Landscapes
- Control Of Positive-Displacement Air Blowers (AREA)
Abstract
The invention relates to an automatic gain scheduling method for wind power plants distributed as the priority level according to blower involvement and belongs to the technical field of energy management system of power systems. The automatic gain scheduling method includes classifying blowers into common blowers and marker blowers according to power generation capacity of the blowers and scheduling the same in a gain manner, and giving the priority to involving all the marker blowers to generate power; classifying the marker blowers from low to high by a first level, a second level and a third level; giving the priority to involving all the blowers at high level to generate power; performing no power ration control at the third level which is the highest level; receiving gained control targets of dispatching, wherein when the gained control targets are larger than or equal to loading capacity, the dispatching command is that all the blowers generate power freely; when the gained control targets are smaller than the loading capacity, power ration control on blower involvement is performed; when on-grid gain is smaller than the gained control targets *95%, guaranteeing complete involvement of the marker blowers at the first level, the second level and the third level according to the sequence, and then adjusting the common blowers. The automatic gain scheduling method is simple and easy to realize, power generation capacity of the wind power plants can be increased, and fault rate of the blowers can be decreased.
Description
Technical Field
The invention belongs to the technical field of Energy Management Systems (EMS) of power systems, and particularly relates to an automatic active power dispatching method for a wind power plant, which considers the power of a fan and distributes the power according to priority.
Background
In recent years, the construction and production of a plurality of large wind power bases in China change the original power supply structure, the influence of wind power on a power grid is gradually increased, and the influence on the peak regulation and frequency regulation of the large power grid is increased from the influence on the reactive voltage of a local power grid. The technical regulation of wind power plant access to grid released by the national grid company indicates that: the wind power plant has active power regulation capability and can control the active power output according to the instruction of a power grid dispatching department. In order to realize the control of the active power, an active power control system is configured in the wind power plant, and an active power control signal sent by a remote dispatching department is received and automatically executed. According to the specified requirements, an active power automatic control system is actively built in the wind power plant, the requirements of a power grid company are met, the automatic regulation level of the wind power of the power grid is improved, and the stable operation of the power grid is ensured.
The automatic active control (AGC) system in the traditional sense of the power system mainly adjusts thermal generator sets and hydroelectric generator sets, and plays an important role in ensuring the stability of the frequency of a power grid. By taking the successful operation experience of an AGC module in an original EMS system for power grid dispatching as reference, the wind power active automatic control system can achieve active power control of dozens of wind power units in a large wind power plant by controlling and adjusting the active power of the wind power plant on line according to the real-time information of the EMS and the real-time data acquisition system of the wind power plant, the system power generation plan and the power prediction system information of the wind power plant.
In actual operation, each large wind farm is regarded as a unit by the power grid dispatching terminal AGC system and serves as a control object of the system. And the power grid dispatching terminal AGC system calculates an instruction by referring to a power generation plan and a wind power prediction result, and then sends an active power instruction to a wind power plant terminal AGC module. And the wind power AGC module calculates the active output target of each fan through distribution according to the received active power dispatching instruction, and finally issues the target to each fan to realize the regulation of the fan power.
In consideration of active loss of a current collection circuit, a transformer and the like in the wind power plant, the active power instruction at the dispatching end actually refers to the total active power of the power output circuit of the wind power plant on the internet, rather than the total sum of the active power of all fans in the wind power plant. In reality, for simplifying system wiring, a return circuit is mostly adopted for accessing a wind power plant into a power system, and at the moment, an active power instruction issued to the wind power plant by a dispatching terminal is only one numerical value. Although the AGC module of the wind power plant needs to control the active power output of dozens of fans in the plant, the total online active power of a transmission line of the wind power plant can finally reach a dispatching active control instruction value.
At present, the wind power plant puts higher requirements on the optimized operation of the wind turbine generator set according to the aims of 'electric quantity robbing and efficiency improvement'. For example, a fan with excellent performance and good wind power condition is required to be selected as a benchmark fan, so that the utilization hour of a wind power plant is favorably improved; the wind turbines in the wind power plant have different power generation capacities due to factors such as geographical positions, equipment performance and seasonal variation, and the operation of the wind turbines with large output is preferentially ensured; the fan is installed in a remote place with a poor geographical environment, and the fan is difficult to maintain due to faults caused by various natural reasons (such as large snow road sealing, difficult driving and the like), so that the operation of the fan is reduced as much as possible, and the fault occurrence rate is reduced. The traditional two wind power plant active control methods according to proportion, margin and the like do not meet the new requirements any more, and a new wind power plant active control method needs to be researched to adapt.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides an automatic active power dispatching method of a wind power plant distributed according to the output of fans and priority levels, which is simple and easy to implement, can give full play to the active power output capability of fans with different performances, has more fans with good performances for generating power and less fans with poor performances for regulation, thereby improving the power generation capacity of the wind power plant and reducing the failure rate of the fans.
The invention provides a method for automatically scheduling active power of a wind power plant distributed according to the output of fans and priority levels, which comprises the following steps of:
1) the method comprises the following steps of dividing a fan into two types of a common fan and a benchmark fan according to the power generation capacity of the fan to perform active scheduling, and preferably ensuring that the benchmark fan is fully used;
2) the level from low to high of the benchmark fan is divided into a first level, a second level and a third level; the high-level priority is full; the grade of the third level is highest, and no electricity limiting control is performed:
3) receiving and dispatching an active control target, wherein when the active control target is larger than or equal to the installed capacity, a dispatching instruction is as follows: all fans generate electricity freely;
4) the active control target is less than the installed capacity, and the power limit control is carried out on the output of the fan;
4.1) the active control target is greater than the power sum of the benchmark fans, and the scheduling instruction is as follows: and only adjusting the common fan, and averagely distributing the difference value of the active control target and the power sum of the benchmark fan to the common fan.
4.2) the active control target < total of the benchmark fans, the scheduling instruction is: stopping all common fans, and enabling the down-marking pole fan to have active power to a control target: if the number of the first-time-series terminal,
4.2.1) the active sum of the second and third grade benchmark fans is less than the active control target and less than the active sum of the benchmark fans, and the output of the first grade benchmark fan is reduced; if the number of the first-time-series terminal,
4.2.2) the active sum of the third-level benchmark fan is less than the active control target, and the active sum of the second-level and third-level benchmark fans is less than the active control target, the first-level benchmark fan is stopped, and the second-level benchmark fan is lowered;
5) the active power of the internet is < 95% of the active control target, and then the scheduling instruction is as follows: the (rising active power) ensures that the third-level, second-level and first-level benchmark fans are fully started in sequence, and then the common fan is adjusted.
The method for automatically controlling the active power of the wind power plant in consideration of the fan output and distributed according to priority has the advantages that: aiming at the active control characteristics of different priority levels required by wind power plant fans due to equipment performance difference, geographical position difference and the like, the method divides a plurality of wind power generation sets (dozens to hundreds) of the wind power plant into a benchmark fan and a non-benchmark fan, and the benchmark fan generates power preferentially. In the benchmark fans, the benchmark fans are divided into a first level, a second level and a third level respectively, the benchmark fans with the high levels generate electricity preferentially, and the third-level benchmark fans do not limit electricity. Engineering practice shows that the method is simple and easy to implement, the active output capacity of fans with different performances can be fully exerted, more fans with good performances generate electricity, and less fans with poor performances are adjusted, so that the generating capacity of a wind power plant is improved, and the failure rate of the fans is reduced.
Detailed Description
The automatic scheduling method of the invention is introduced in the following specific embodiment of the active automatic scheduling of the wind power plant in consideration of the output of the fan and distributed according to priority level of a certain wind power plant:
the total installed capacity of the wind power plant of the embodiment is 99.5MW, and the wind power plant comprises 33 first-stage combined power fans of 1.5MW and 25 second-stage Chongqing sea fans of 2.0 MW. The specific scheduling method comprises the following steps:
1) the method comprises the following steps of dividing a fan into two types of a common fan and a benchmark fan according to the power generation capacity of the fan to perform active scheduling, and preferably ensuring that the benchmark fan is fully used;
2) the level from low to high of the benchmark fan is divided into a first level, a second level and a third level; the high-level priority is full; the grade of the third level is highest, and no electricity limiting control is performed:
the wind farm fans of the present embodiment are distributed on 4 collector wires in the farm. According to the influence of the wake flow fluctuation of the fans on the active power of the fans, the first fan, the fan in the middle position and the last fan on each current collecting line are used as benchmark fans and are respectively classified into three stages, two stages and one stage; the high-level priority is full; the grade of the third level is highest, and no electricity limiting control is performed: in this example
The primary benchmark fan is 8.5 MW: wherein,
the first period is as follows: a #20 fan, a #25 fan, a #33 fan,
The second stage is as follows: a #46 fan and a #47 fan;
the secondary benchmark fan is 7MW in total:
the first period is as follows: a #1 fan and a #15 fan;
the second stage is as follows: a #40 fan and a #58 fan;
the three-level benchmark fan is 7MW in total:
the first period is as follows: a #3 fan and a #16 fan;
the second stage is as follows: a #34 fan and a #52 fan;
ordinary fan
26 first-stage devices are respectively:
a #2 fan, #4 to #14 fans, #17 to #19 fans, #21 to #24 fans, and #26 to #32 fans;
a second stage 19, which are respectively:
fans #35 to #39, #41 to #45, #48 to #51, and #53 to # 57;
3) receiving and dispatching an active control target, wherein when the active control target is larger than or equal to the installed capacity, a dispatching instruction is as follows: all fans generate electricity freely;
4) the active control target is less than the installed capacity, and the power limit control is carried out on the output of the fan; the method specifically comprises the following steps:
4.1) the active control target is greater than the power sum of the benchmark fans, and the scheduling instruction is as follows: only adjusting the common fan, and averagely distributing the difference value of the active control target and the power sum of the benchmark fan to the common fan;
4.2) the active control target < total of the benchmark fans, the scheduling instruction is: stopping all the common fans, wherein the active power of the down-marking pole fan reaches a control target: if the number of the first-time-series terminal,
4.2.1) the active sum of the second and third grade benchmark fans is less than the active control target and less than the active sum of the benchmark fans, and the output of the first grade benchmark fan is reduced; if it is
4.2.2) the active sum of the third-level benchmark fan is less than the active control target, and the active sum of the second-level and third-level benchmark fans is less than the active control target, the first-level benchmark fan is stopped, and the second-level benchmark fan is lowered;
5) the active power of the internet is < 95% of the active control target, and then the scheduling instruction is as follows: active power rising: the third-level, second-level and first-level marker post fans are ensured to be fully started in sequence, and then the common fan is adjusted.
The following illustrates the active scheduling method in this embodiment by exemplifying 4 exemplary scheduling instructions:
(1) and the active control target is scheduled to be 99.5MW, then: the power control target 99.5MW is more than or equal to the installed capacity 99.5MW, and the scheduling instruction is as follows: free power generation;
2) the active control target 60MW and the benchmark fan power sum 22.5MW are dispatched, then the active control target 60MW > the benchmark fan power sum 22.5MW, and the dispatching instruction is as follows: only the common fans are adjusted, the active control value of each fan in one period is (60-22.5) × (1.5 × 26/(1.5 × 26+2 × 19))/26 ═ 0.73,
second stage (60-22.5) × (2 × 19/(1.5 × 26+2 × 19))/19 ═ 0.97;
(3) and scheduling an active control target 20 and a benchmark fan power sum 22.5, wherein the active sum 14 of the second and third levels of benchmark fans is less than the active control target 20 and less than the benchmark fan active sum 22.5, and the scheduling instruction is as follows: reducing the output of only one stage of the scalar fan, wherein the active control value of each stage of the scalar fan in the first stage is (20-14) × (1.5) × 3)/8.5/3 ═ 1.06, and the active control value of each stage of the scalar fan in the second stage is (20-14) × (2) × (8.5)/2 ═ 1.41;
(4) scheduling an active control target 10 and a benchmark fan power sum 22.5, wherein the active sum 7 of the three-level benchmark fan is less than the active control target 10 and less than the active sum 22.5 of the two-level and three-level benchmark fans, and scheduling instructions are as follows: stopping all the common fans and the primary index rod fans, reducing the output of the secondary index rod fans, wherein the active control value of each secondary index rod fan in the first period is (10-7) × (1.5) × 2)/7/2 ═ 0.64, and the active control value of each secondary index rod fan in the second period is (10-7) × (2) × (7/2 ═ 0.86.
Claims (1)
1. A wind power plant active power automatic scheduling method distributed according to fan output and priority levels is characterized by comprising the following steps:
1) the method comprises the following steps of dividing a fan into two types of a common fan and a benchmark fan according to the power generation capacity of the fan to perform active scheduling, and preferably ensuring that the benchmark fan is fully used;
2) the level from low to high of the benchmark fan is divided into a first level, a second level and a third level; the high-level priority is full; the grade of the third level is highest, and no electricity limiting control is performed:
3) receiving and dispatching an active control target, wherein when the active control target is larger than or equal to the installed capacity, a dispatching instruction is as follows: all fans generate electricity freely;
4) the active control target is less than the installed capacity, and the power limit control is carried out on the output of the fan; specifically, the method comprises the following steps of;
4.1) the active control target is greater than the power sum of the benchmark fans, and the scheduling instruction is as follows: and only adjusting the common fan, and averagely distributing the difference value of the active control target and the power sum of the benchmark fan to the common fan.
4.2) the active control target < total of the benchmark fans, the scheduling instruction is: stopping all common fans, and enabling the down-marking pole fan to have active power to a control target: if the number of the first-time-series terminal,
4.2.1) the active sum of the second and third grade benchmark fans is less than the active control target and less than the active sum of the benchmark fans, and the output of the first grade benchmark fan is reduced; if the number of the first-time-series terminal,
4.2.2) the active sum of the third-level benchmark fan is less than the active control target, and the active sum of the second-level and third-level benchmark fans is less than the active control target, the first-level benchmark fan is stopped, and the second-level benchmark fan is lowered;
5) the active power of the internet is < 95% of the active control target, and then the scheduling instruction is as follows: the third-level, second-level and first-level marker post fans are ensured to be fully started in sequence, and then the common fan is adjusted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410390674.7A CN104124715A (en) | 2014-08-11 | 2014-08-11 | Automatic gain scheduling method for wind power plants distributed as priority level according to blower involvement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410390674.7A CN104124715A (en) | 2014-08-11 | 2014-08-11 | Automatic gain scheduling method for wind power plants distributed as priority level according to blower involvement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104124715A true CN104124715A (en) | 2014-10-29 |
Family
ID=51770029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410390674.7A Pending CN104124715A (en) | 2014-08-11 | 2014-08-11 | Automatic gain scheduling method for wind power plants distributed as priority level according to blower involvement |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104124715A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105978041A (en) * | 2016-03-23 | 2016-09-28 | 三重型能源装备有限公司 | Active power control method for wind power station configured with marker post draught fans |
| CN109347122A (en) * | 2018-11-21 | 2019-02-15 | 国电联合动力技术有限公司 | Wind power plant template processing machine participates in the intelligent control method and its control system of active adjusting |
| WO2019165637A1 (en) * | 2018-03-02 | 2019-09-06 | 国网冀北电力有限公司 | Wind farm cluster active power control method and apparatus |
| CN111835041A (en) * | 2020-08-12 | 2020-10-27 | 山西粤电能源有限公司 | Active power control method for wind power plant |
| CN111950780A (en) * | 2020-07-31 | 2020-11-17 | 许继集团有限公司 | Wind power plant short-term power prediction method |
| CN115313528A (en) * | 2022-10-11 | 2022-11-08 | 力高(山东)新能源技术股份有限公司 | AGC active power adjusting method for new energy power station |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2084801B1 (en) * | 2006-10-26 | 2010-05-05 | KAESTLE, Gunnar | Method for operating a low-voltage electrical system |
| CN102510093A (en) * | 2011-12-19 | 2012-06-20 | 国网电力科学研究院 | Wind power field active power control method based on power forecasting information |
| CN102856931A (en) * | 2012-06-15 | 2013-01-02 | 中国电力科学研究院 | Wind power plant active power dynamic grouping control method |
| CN103187736A (en) * | 2013-01-18 | 2013-07-03 | 云南电网公司大理供电局 | Active dispatching system containing wind power plant |
-
2014
- 2014-08-11 CN CN201410390674.7A patent/CN104124715A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2084801B1 (en) * | 2006-10-26 | 2010-05-05 | KAESTLE, Gunnar | Method for operating a low-voltage electrical system |
| CN102510093A (en) * | 2011-12-19 | 2012-06-20 | 国网电力科学研究院 | Wind power field active power control method based on power forecasting information |
| CN102856931A (en) * | 2012-06-15 | 2013-01-02 | 中国电力科学研究院 | Wind power plant active power dynamic grouping control method |
| CN103187736A (en) * | 2013-01-18 | 2013-07-03 | 云南电网公司大理供电局 | Active dispatching system containing wind power plant |
Non-Patent Citations (1)
| Title |
|---|
| 谢永俊: "风电场内有功功率控制研究", 《中国优秀硕士学位论文全文数据库》 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105978041A (en) * | 2016-03-23 | 2016-09-28 | 三重型能源装备有限公司 | Active power control method for wind power station configured with marker post draught fans |
| CN105978041B (en) * | 2016-03-23 | 2019-06-18 | 三一重型能源装备有限公司 | A kind of wind power station active power control method configuring mark post blower |
| WO2019165637A1 (en) * | 2018-03-02 | 2019-09-06 | 国网冀北电力有限公司 | Wind farm cluster active power control method and apparatus |
| US11451066B2 (en) | 2018-03-02 | 2022-09-20 | State Grid Jibei Electric Power Company Limited | Control method and device for active power of wind power plant cluster |
| CN109347122A (en) * | 2018-11-21 | 2019-02-15 | 国电联合动力技术有限公司 | Wind power plant template processing machine participates in the intelligent control method and its control system of active adjusting |
| CN109347122B (en) * | 2018-11-21 | 2022-01-25 | 国电联合动力技术有限公司 | Intelligent control method and system for participating in active power regulation of wind power plant sample board machine |
| CN111950780A (en) * | 2020-07-31 | 2020-11-17 | 许继集团有限公司 | Wind power plant short-term power prediction method |
| CN111835041A (en) * | 2020-08-12 | 2020-10-27 | 山西粤电能源有限公司 | Active power control method for wind power plant |
| CN115313528A (en) * | 2022-10-11 | 2022-11-08 | 力高(山东)新能源技术股份有限公司 | AGC active power adjusting method for new energy power station |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Weisser et al. | Instantaneous wind energy penetration in isolated electricity grids: concepts and review | |
| US9559520B2 (en) | Hybrid electric generating power plant that uses a combination of real-time generation facilities and energy storage system | |
| CN102361330B (en) | Active power optimizing and distributing method for wind generator unit of wind power station | |
| CN104124715A (en) | Automatic gain scheduling method for wind power plants distributed as priority level according to blower involvement | |
| CN104362680B (en) | With the active power of wind power field auto-allocation method of the minimum target of active loss | |
| CN103066626A (en) | Multi-source coordinating day-ahead generation scheduling method | |
| CN110601254B (en) | Wind power plant energy storage optimization configuration method and system considering dynamic current-carrying characteristics | |
| Teng et al. | Provision of ancillary services in future low-carbon UK electricity system | |
| CN103928924A (en) | Wind power plant active power optimal control method considering maximum active power change value | |
| El-Naggar et al. | Ranking subassemblies of wind energy conversion systems concerning their impact on the overall reliability | |
| Moness et al. | A critical review of research trends for wind energy in Egypt: recent progress and promising opportunities | |
| Ebert et al. | Successful high wind penetration into a medium sized diesel grid without energy storage using variable speed wind turbine technology | |
| CN105914798A (en) | Wind power field reactive power optimization operation control method based on whole network same time section | |
| CN113592125B (en) | Matching optimization comparison selection method and system for extra-high voltage direct current matched power supply | |
| CN110417023B (en) | Configuration and operation control method for distributed static series compensator | |
| Liao et al. | Optimal Capacity Allocation for Wind-Solar Station Considering Power Response of Pumped Storage | |
| Al Riyami et al. | Integration of 50MW Dhofar Wind Farm Intermittency in System Planning & Operation | |
| Pasca et al. | Characterization of wind and solar generation and their influence on distribution network performances | |
| Wu et al. | Integration of large-scale renewable power into the Taiwan power system | |
| Yipei et al. | Distribution network planning considering offshore wind-tide-virtual energy storage system | |
| Xu et al. | Study on active power control in DFIG-based wind farm | |
| Akhtar | Analysis of Simris hybrid energy system design and working and checking the effects of using high capacity factor wind turbine | |
| Gözde et al. | Integration of renewable energy sources into turkey electric energy network general problems and solution proposals | |
| Wang et al. | Analysis of the impact of heating-thermal generators flexibility expansion on promoting renewable energy integration based on production cost simulation | |
| Wang et al. | Combined output offshore wind-tide-virtual energy storage system model |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20141029 |