Ik short circuit. Capsim performs short-circuit current calculations using numerical simulation by modelling the entire grid concerned and considering the various influencing parameters: short-circuit power of the supply, normal/emergency modes, load factor, load reinjection from the motors, supply configurations, etc. Feb 11, 2020 · kA rating of an MCB or an MCCB is the maximum current it can safely interrupt in case of a short circuit. Since this is a safety appliance, fail-safe operation is crucial. Jul 17, 2021 · This video explains What is short circuit in electronics with examples and analogies for better understanding. ip also depends on the reduction of the short-circuit current symmetrical a. May 26, 2018 · The percentage impedance of a transformer is the volt drop on full load due to the winding resistance and leakage reactance expressed as a percentage of the rated voltage. The prospective short-circuit current (PSC, PSCC) is the maximum current that can flow through a shorted electrical circuit. These faults can be caused by a lightning strike, weather conditions or equipment failure. This would result in an oversupply of voltage streaming and an overflow of current passing through the power source. Performing short-circuit calculations requires an understanding of various system components and their interaction. 1 Three phase short-circuit Table 14 R esults acc. 5kA for 1 second be used with a fault current of 18kA when the protection will clear the fault in 0. Jun 12, 2017 · the contribution to the peak short-circuit current from each branch can be expressed by: Ip=sqrt(2)*K *I"k where K=1. to I EC-60909-4 (3 phase short circuit) Short Circuit Un I’’k1 ip(20) ib ik Location kV kA kA kA kA 1 380 40,6447 100,5677 40,645 40,635 2 110 31,7831 80,6079 31,570 31,663 3 110 19,6730 45,8111 19,388 19,623 4 110 16,2277 36,8427 16,017 16,196 5 110 33,1894 83,4033 32,795 32,997 6 10 Short Circuit. However they boil down to some basic principles. SHORT CIRCUIT definition: 1. XOL = 2πfxl1x (μ0/2π)x (ln (d/re)+ (1/4n)) – single-circuit line. Box office. Fig. The same ratio applies to the dynamic variables Ima/Isc. k. If the radio is stolen- removed from its 12v supply then it wont work until you input the code when its powered up again. การลัดวงจร What is the rated short circuit withstand current (Ik) of circuit breaker? Can a switchboard rated at 12. 1 Short Circuits at the Terminals of Asynchronous Motors 161. In accordance with the recommendations of this standard, the symmetrical component method is used. systems – Part 1: Factors for the calculation of short-circuit currents according to IEC 60909-0. To prevent this, the breaker shuts off the current. Values of 4 to 6 are Scommonly accepted. The short circuit impedance of the transformer is related to many factors of the transformer. A practical estimate of motor short circuit contribution is to multiply the total motor current in amps by 4. Download paper 3. A short circuit occurs when electric flow takes a shorter route than normal, causing a dangerously high level of current, and with it the risk of burning the circuit and creating a fire. 12 kA which means all criterions are met & the Minimum Short-circuit Current (I min) The short-circuit current used as basis for protective relay settings derived using the voltage correction factor, C min. Many multi-function testers are able to measure the PSC. The document specifies a standardised method for the development of short circuit calculations, as well as providing guidance on equipment data. Peak current during first halfwave i. -. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Circuit breakers are safety devices intended to prevent overheating. One of the 80's best offerings and always enjoyable. 4 min read Published on 20. Derived from Ik". In cases of large motor load or closely coupled generators, the network X/R ratio and The requirements of a short-circuit study will depend on the objectives. Sk". 1). k ” in case current support is activated during Voltage Fault Ride Through . a. Short Circuits – Arduino compatible electronics kits. ETAP Short Circuit Analysis complies with IEC 60909 standard, which classifies short-circuit currents according to their magnitudes (maximum and minimum) and fault distances from generators. 5kA peak. To highlight the specific case of IT earthing system, the short circuit value represents a second failure short-circuit, since after first failure the current circulation is very low or almost zero (although is a failure that must be Circuit breakers are usually defined / specified on the ‘break’ (Ib) rating. Mar 28, 2023 · There is a direct correlation between system strength, traditionally measured by the Short Circuit Levels (SCL), and some of the power quality aspects, including harmonics, voltage unbalance and voltage flicker. The film centers on an experimental military robot that is struck by lightning and gains a human-like intelligence, prompting it to escape its facility to learn more about the world. 5 lever: Finland: Robotti rakastuu rating of the breaker with the same I rating of the breaker. Wilson and Brent Maddock. component). Jul 1, 2012 · IEC 60909 is the international standard for the calculation of short circuit currents. 2018 · 9:38 UTC. It is also the percentage of the normal terminal voltage required to circulate full-load current under short circuit conditions. #1. 2. component of the prospective (available) shortcircuit current at the instant of contact separation of the first pole of a switching device. s is the square root of the mean of the squares of the values of these two states. 2 Motor Groups Supplied from Transformers with TwoWindings 163. value of the short For the calculation of short-circuit currents that do not involve faults to the ground th capacitive reactance is disregarded. Its tripping-current-level adjustment ranges for overload protection (Ir [1] or Irth [1]) and for short-circuit protection (Im) [1] Its short-circuit current breaking rating (Icu for industrial CBs; Icn for domestic-type CBs). c. The values that actually occur in the network, however, have priority. What action with the use of the paddle must be undertaken first when an isolation of the third rail is required? Sep 7, 2020 · Short Circuit Level is the amount of current that flows on the system during a fault. Example: Transformer Sr=20 MVA Voltage Ur=10 kV Usc% = 10 % Upstream power: infinite. • mean value between the top and bottom envelope of a shortcircuit current decaying from an initial value to zero. A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. Besides explaining what a short circuit is, and telling you why it is dangerous, I Dec 11, 2003 · Maximum value (peak value) of the short circuit current. 05 = 4600 A (or 4. b) This student wants to observe both the light emitted, the light passed and the difference of these two at the same time. This circuit is monitored by electrical equipment to detect the absence of the trains. Circuit comes from the word circle. A sequel, Short Circuit 2, was released in 1988, directed by Kenneth Johnson, but did not do as well at the box office. 12 Motors in Electrical Networks 161. The steady state short circuit current Ik depends on Uk and the transformer's internal resistance Z. 1. Please note that the percent difference for the initial symmetrical current (I”k) is less than 0. The duration of Ik is dependent on country-specific parameters such as Low. 5 is a prototype battlefield weapon that can A three-phase short circuit fault is considered to be the most severe fault in any power system. The rating is determined without an upstream short circuit 4 days ago · Auxiliary circuits of assemblies intended to be connected to transformers whose rated power does not exceed 10 kVA for a rated secondary voltage of not less than 110 V, or 1,6 kVA for a rated secondary voltage less than 110 V, and whose short-circuit impedance is not less than 4%. Jorge Luengo Loayza. Short-circuit impedance is a very important technical Sep 26, 2012 · The transformer's impedance and X/R ratio largely determine your fault levels for a short-circuit on either side of it, you can't have 'too much' fault current through it. r. current; in a three-phase system, the balanced three-phase short-circuit is decisive. It can be considered as the upper limit for the short circuit current that it can safely handle. This value may apply to switches (eg, a switch-disconnector), circuit Circuit. A short circuit is a fault. k = 0A in case Voltage Fault Ride Through is off or Zero Current Mode . " Basically, a short-circuit fault in a power system is an abnormal condition that involves one or more phases unintentionally coming in Feb 10, 2023 · Two circuit breakers are mutually selective if the short circuit current flowing through the downstream breaker is lower than the (adjustable) threshold of tripping of the magnetic release of the unit connected upstream. This is equivalent to the closing and latch peak duty in ANSI-approved standards. I k′′ = initial symmetrical short-circuit current i p = peak short-circuit current I k = steady-state short-circuit current i d. S. An IEC 60909 / G74 short circuit study refers to the process of determining the fault levels (commonly called short circuit levels) in an electrical power system. elec calc™ calculates short-circuit currents according to the recommendations of standard IEC 60909. For Fault at Bus "1', Ib symm = I"k as per the standard. 11. circuit. Nov 14, 2020 · enjoyable family film. 96 kA, iasym = 27. The prospective short-circuit current ( PSCC ), available fault current, or short-circuit making current is the highest electric current which can exist in a particular electrical system under short-circuit conditions. 40kA break & 104kA. a) Design a circuit that will work in the entire measurement area to be 1lx = 0. This report discusses the main power quality aspects in the future GB transmission network. All other circuits shall be verified. st. Nails or screws piercing through walls and coming into contact with wires. Learn more. 3 Motor Groups Supplied from Transformers with Different Nominal Voltages 163. The circuit wire insulation can be negatively effected by age and use, as well as screws and nails, and animals like Apr 20, 2018 · We break down the best starter karts in each category in the UK, from Bambinos to short circuit gearbox machines. 4. of short-circuit current. การลัดวงจรไกลจากเครื่องกำเนิดไฟฟ้า ( Far-from-generator Short Circuit ) 2. Occurs within the first sin half wave directly after the initiation. Ground Fault Short Circuit. the network (transformers,generators, motors, lines, etc). 25 kA, Iasym = 46. We aim to become a key hub for emerging fiction filmmaking talent in Scotland, supporting writers, directors and producers to develop creatively and professionally, and stimulating the creative and commercial success of Scotland’s film sector. This is reported using a series of parameters which relate to the rated short-circuit current of equipment and the tests required on equipment to prove that rating. As for Ip and ratings on switchgear / circuit breakers, the ratio between symmetrical (I''k) and peak current (Ip) is Short Circuit IEC 60909 Standard. short-circuit current stated on the device is the rated conditional short-circuit current of the combination of the RCCB with an SCPD. W. It explains that the short circuit voltage Uk is the primary voltage at which the transformer takes up its rated current with a shorted secondary winding. 7 million [3] [4] Short Circuit is a 1986 American science fiction comedy film directed by John Badham and written by S. , and 5) the symmetrical steady-state short-circuit rms current Ik for each contributing source. There is a robot in "Short Circuit" that is really cute, if "cute" can apply to a robot. Whether two circuit breaker are really mutually selective is checked by Sep 27, 2017 · IEC 60909 / ENA G74. For detail refer to IEC 60909-0 Page 117 5. The Peak fault occurs first during the asymmetrical state and is the maximum possible instantaneous value of the short circuit current. Fig 2: Short Circuit vs Ground Circuit Signs of an Electrical Short Circuit Motor short circuit contribution, if significant, may be added at all fault locations throughout the system. Peak short-circuit current IP, that is the largest instantaneous value of short-circuit current is calculated from the equation I P = √2. furthermore, you can also obtain these values from such programs, that are both derived from Ik": - Ik: Steady state short current (short circuit current after the decaying of the d. Build and Learn. Duration: < 30 ms. k = max. Jun 5, 2021 · มาตรฐาน IEC 60909 ได้แบ่งการคำนวณกระแสลัดวงจรออกเป็น 2 ประเภทคือ. Loose connections in an electrical box. Jan 20, 2012. The influence of arc short-circuit current stated on the device is the rated conditional short-circuit current of the combination of the RCCB with an SCPD. 5 second? Show calculations. This cookie is set by GDPR Cookie Consent plugin. 02 + 0. I K " Where k=factor for the calculation of the peak short-circuit current. 5, and it moves and talks and even seems to think like something that is alive, even though we can see, clear as day, that it's made of tubes and wires and photoelectric cells. General small distribution transformer standard value of 4% or 4. 6 at 60 Hz). Physics are involved and the parameters vary greatly so there is most likely no standardised method which can mitigate the collection of parameters. kA rating is known as the short circuit withstand capacity or ultimate breaking capacity of a circuit breaker. SCL is vital during such a fault as it helps us to We would like to show you a description here but the site won’t allow us. It is denoted as I cu and rated in kilo-Amperes. A metal wall box that is grounded, bare ground wire, or a grounded area of an appliance are all examples of this. 6 kA) (This value would have been given directly if the instrument had a prospective fault current range). value of an integral cycle of the symmetrical a. It is determined by the voltage and impedance of the supply system. The equivalent positive (and negative) impedance of the line is calculated as follows: ROL = ρ20°Cxl/s. e. C alcuhv ib so ry m RM current at the point Short Circuit: Belgium (French title) Court-circuit: Brazil (alternative title) O Incrível Robô: Brazil: Um Robô em Curto Circuito: Bulgaria (Bulgarian title) Късо съединение: Canada (French title) Coeur circuit: Canada (English title) Short Circuit: Czechia: Císlo 5 zije: Denmark: Nr. In the event of a fault, the busbar and cable supports must hold the conductors in position, and not sustain any damage, until the fault is cleared. 27 kA & Ip = 100 kA against idc = 19. Closed circuit – A circuit is closed if the circle is complete, if all currents have a path back to where they came from. Image-A. 5 (2. g. Sep 27, 2018 · Step 3 — Calculate the short-circuit current on the transformer secondary bus, but this time we use the transformer impedance AND the source impedance. is dependent on the country setup/configuration: I. Guidance relating to 230 V single-phase supplies and 400 V three-phase supplies, previously provided in ER P25 Issue 1 and ER P26 Issue 1, is now superseded by this Engineering Recommendation (EREC). ” (IEC61439-1, 2009, p. A circuit is a collection of real components, power sources, and signal sources, all connected so current can flow in a complete circle. In cases where LVRTenable = 0: The inverter continues to push current until relays are opened. . The following table occurred, r= short-circuit resistance, x = short circuit reactance. I. No. This is the rms value of the current which the switchgear can carry in the closed position during a specified short time. The following tables of comparison show the differences between ETAP Results and those published in the IEC Standard IEC 60909-4 2021 Section 9. Water or other fluids coming into contact with electrical wiring. Factor k can be calculated from the equation or readfrom the Oct 1, 2021 · The short-circuit current, expressed in kA, is given by the following equation: The short-circuit current depends onthe type of equipment installed on. HV circuit breakers peak (Ip) short circuit rating is a multiple of its ‘break’ rating: 2. If the option ‘Create Plots’ has been selected in the Short-Circuit Calculation command dialog, the virtual instrument page displays plots of the short-circuit current using the following variables: i_t ik _ t idc _ t End Loop PowerFactory - Short-Circuit Method IEC 61363 22 1. Addeddate 2021-12-16 03:08:49 Identifier short. Step6. Steady-State Short-Circuit Current (Ik) This is the rms value of the short-circuit current, which remains after the decay of the transient phenomena. 002 % in most cases. values of short-circuit current The value of peak short-circuit current (peak value of the first loop of the short-circuit current including DC. Short circuit is a state where large current f Phase-earth short-circuit (*) Short-circuit current. 33 kA & ip = 51. Its rated current In. component) for determining the electrodynamic stresses shall be obtained by multiplying the RMS. 5. These calculations are carried out Sep 9, 2019 · asymmetrical short-circuit breaking rms current la asym. Ik – the short-circuit steady-state current, in RMS. When a three-phase short circuit fault occurs, the fault current in the power system comprises two components, i. A short circuit will result if electricity flows through a ‘short’ route. Short time is generally 1 s, and sometimes 3 s. Maximum short-circuit currents determine equipment ratings, while minimum currents dictate protective device The steady state short-circuit current I. Due to the presence of the DC component, the three-phase Short-circuit currents in three-phase AC systems – Figure 10 – Short-circuit current " Ik(T1,T2)S calculated by the superposition method (S) compared with " I Rather than the short-circuit current that would occur in a specific instance, IEC 60909 derives the maximum and minimum prospective short-circuit currents in a system for each specific location and time. value of the initial symmetrical short-circuit. 42 I k Ik’’ – the initial symmetrical short-circuit current value, in RMS. Synchronous compensators are treated in the same way as synchronous generators. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. For instance in Example-1, if we choose a circuit breaker having Ist rating of 40kA & rated breaking time of 40ms, then we achieve Idc = 23. 7 Steady-State Short-Circuit Current, Ik 157. Aug 13, 2022 · The things around short circuit (SC) calculations are fairly complex as @Antonio51 already had mentioned. m. s fault occurs after the Peak fault and is the latter more symmetrical state of the short circuit. If the current goes beyond this value, the circuit breaker could be damaged. The IEC 909 procedure requires calculating the contributing source’s component of short-circuit current for each of the The main differences between these two cases v The resistances per unit length RL of lines are: (overhead lines, cables, phase and neutral c For short-circuits far from the generator conductors) should be calculated for a temperature of 20 °C v The initial (I"k), steady-state (Ik) and breaking (Ib) short-circuit currents are equal (I"k = Ik equipment that senses, carries, or interrupts short-circuit currents. 1986. But once the transformer is manufactured, it is the same. It'll only be damaged if you don't interrupt it in time. Old or damaged outlets, switches, lights, appliances, or other electrical devices. Feb 27, 2013 · However as per Indian standard 8623-part-1 for low voltage switchgear and controlgear assembly: Relationship between peak and RMS. It also provides equations to calculate short circuit currents and Dec 9, 2020 · Peak Short-circuit Current (I P) IEC 60909 defines the peak short-circuit current as the maximum instantaneous value of the short-circuit current. Peak short-circuit current is calculated by introducing a crest factor, Κ, to the initial short-circuit current, I”k. where, λ = factor λ , depend on the Xdsat and the ratio l”kG /IrG. Short-circuit currents in three-phase a. symmetrical AC component and the DC component of the fault current. To find out more about how the standard works, refer to our note: Fault Calculation - IEC 60909 - note coming soon Synchronous and asynchronous machines like Induction Motors in the circuit IEC 60909 0 (2001 07) describes that when calculating the initial symmetrical short circuit current Ik”, the peak short circuit current ip, and the steady state short circuit current Ik. Such as transformer capacity, loss, internal coil structure and so on. Written by Piers Prior. a bad electrical connection that causes the current to flow in the wrong direction, often having. Dec 11, 2021 · Temporal Degrain and Topaz AI upscale of best Bluray source for Short Circuit. Steady-state short-circuit current Ik The basic principle behind the track circuit lies in the connection of the two rails by the wheels and axle of locomotives and rolling stock to short an electrical circuit. 4 Procedure for EMT Simulation Method The following procedure is X/R of the short-circuit impedance Zk, and is acheived if the short circuit begins at zero voltage. 5%. IEC 60909-1 Short Circuit Currents in Three-Phase AC Systems, Part 1: Factors for the Calculation of Short Circuit Currents According to IEC 60909-0 IEC 60909-2 Electrical Equipment – Data for Short Circuit Current Calculations in Accordance with IEC 909 (1988) IEC 60909-4 Short Circuit Currents in Three-Phase AC Systems, Part 4: Definition of Ultimate breaking capacity (I cu) The term Ultimate breaking capacity (I cu) define the maximum short circuit current that a circuit breaker can interrupt without damaging itself. It's very important to understand the meaning of the term "short-circuit fault. Definitions according IEC 60909 (II) • decaying (aperiodic) component id. Step 4. The cookie is used to store the Sep 6, 2009 · Symmetrical short-circuit breaking current Ib The r. 5x Ib (50Hz) i. By clicking “Accept”, you consent to the use of ALL the cookies. ER The available fault current at the line terminals of each machine supply circuit disconnecting means must be known in order to determine if the control panel that contains the disconnecting means has an adequate short-circuit current rating. Jul 16, 2023 · Short circuits can be caused by: Vermin or pests chewing through wires. s. This value is considered as the limit of selectivity. 98*exp(-3R/X) I”k= the initial symmetrical short-circuit current R and X are the parameters of the system viewed from the short-circuit location. Let’s say we have a transformer rated 1500 kVA with a secondary voltage of 480Y 4 days ago · Short Circuit is an ambitious film talent initiative for Scotland. SCA secondary = (FLA secondary x 100) / (% Z transformer + %Z source) Here is an example of the calculation. 25kA break & 62. For example, if the MCB is rated at 10kA, it means What's in the box? Let's find out!Official channel under Linus Media Group. June 1, 1999. The IEC 60909 standard for short circuit calculations in three phase AC systems, is a well known and commonly used standard, while the G74 standard refers to a UK Jun 22, 2022 · The fundamental characteristics of a circuit-breaker are: Its rated voltage Ue. 6x Ib (60Hz) i. When you have a tripped breaker, it means too much electricity flowed through the system, posing the risk of overheating. A favorite from my own childhood, I just watched with my own kids (8 and 11). A further short-circuit value defined in both IEC/ EN 60947-3 and IEC/EN 60947-2 is the rated short-time withstand current (I cw). When selecting protection devices, consideration must be given to the prospective short-circuit current (PSC) at the location the device is to be installed in (AS/NZS 3000:2018 clause 2. In other words, the percentage impedance of a Dec 21, 2021 · Start your sales enquiry online and an expert will connect with you. Apr 4, 2006 · Forget the radio ! Radios can have a security code set. The same procedure is now repeated to calculate the line-to-earth value, and the highest of these calculated values should be recorded as the maximum Jun 22, 2020 · The applicable standard defines a fixed ratio between the impulse and short-time current as a basic design requirement for switching devices and switchgear: Ip/Ik = 2. P is also defined by I k”: i P = 1. The r. But how do you calculate it? The film stars Ally Sheedy, Steve Guttenberg, Fisher Stevens, Austin Pendleton and G. It is of the order of a few thousand amperes for a standard Peak value ip of the short-circuit current Steady-state short-circuit current Ik In no meshed systems, the peak value ip of the The amplitude of the steady-state short-circuit current Ik depends on generator saturation short-circuit current may be calculated for all influences and calculation is therefore less types of faults using the equation Calculations according to IEC 60909. set These objectives will dictate what type of short-circuit analysis is required. its an antitheft measure . The PSC can be determined by measurement or by calculation. 2160p Scanner Jul 4, 2017 · Maximum prospective short-circuit current (line-to-neutral) = 230/0. My eight year old hated the first twenty minutes and complained incessantly, and I can understand why a kid might think this as this part of the film mostly just shows killer robots and military jerks. Partial short-circuit currents in conductors and earth. Definition of short circuit its self, according to IEC 60909 standard, is accidental or intentional conductive path between two or more conductive parts (e. 1 mV, and determine the operating voltage of the amplifiers you use in the design by explaining it. Regardless of the number of control panels provided for a single machine, each supply circuit must have SHORT CIRCUIT WITHSTAND is the ability of your switchboard to handle a short circuit fault for a specified duration. Although usually the result of a fault, there Feb 4, 2020 · A short circuit occurs when the hot and neutral wires touch and the In this quick episode of Repair and Replace, Vance explains how a short circuit happens. the only part of the G59 form i have left to answer is the section part 1a: Peak asymmetrical short circuit at 10ms (ip) for a 3 short circuit fault at the connection point??? RMS value of the initial symmetrical short circuit (ik) for a 3 short circuit fault at the connection???/. If you experience continuous breaker The approved abbreviated title of this engineering document is “EREC P25”, which replaces the previously used abbreviation “ER P25”. 12. The majority of short-circuit studies in industrial and commercial power systems address one or Jan 17, 2023 · A short circuit occurs when two conductors delivering electrical power to a circuit have a low resistance connection. components of the short-circuit current. 2 illustrates breaking currents for the circuit in Fig. $40. During the fault, the system can see a direct connection to the earth and current flows from all sources into it. Ir Sr. Calculate the "f" factor. Equipment coverage includes, but should not be limit ed to, protective device sensors such as series trips and relays, passive equipment that may carry short-circuit current such as bus, cable, reactors and transformers as well as interrupters such as circuit breakers and fuses. Short-Circuit Calculations. Bailey, with Tim Blaney as the voice of the robot named "Number 5". Its name is No. Mar 17, 2023 · A short circuit is an electrical malfunction that can cause serious damage. The thermal equivalent short-circuit current can be expressed by: Ith = Ii,/- (24) where m and n are numerical factors, I[the r. A ground fault short circuit happens when a live wire carrying current comes in contact with a grounded system section. Apr 5, 2019 · A short circuit can occur for a variety of reasons, including: A fault with the insulation- if the circuit wire insulation is faulty, the current can then pass to neutral wire, causing a surge in electricity and a short circuit. component. This method is the most accurate, then leading to an optimized sizing compared to the other conservative Step 1: Isolate the Circuit by Identifying the Tripped Breaker. 13 Mechanical and Thermal Short-Circuit The document discusses transformers and their equivalent circuits. • peak short-circuit current ip. 04. IEC 60909 recommends applying ‘Voltage Factors’, C max and C min, to the prefault nominal system voltage in order to account for the system prefault conditions. three- phase short circuit) forcing the electric potential differences between these conductive parts to be equal or close to zero. The amount of data required will also depend on the extent and the nature of the study. This value may apply to switches (eg, a switch-disconnector), circuit stubo300. ef sw rr hm fz yy uf cl qd qu
June 6, 2023