1. A method for computing car switching solutions in a railway switch yard having a plurality of classification tracks, a switch and a switching queue containing a plurality of cars to be sequentially switched by the switch to respective ones of the classification tracks, said method comprising:
a) providing a data processing apparatus having an output, the data processing apparatus being programmed with software to compute car switching solutions;
b) iteratively computing with the software executed by the data processing apparatus a plurality of car switching solution for at least one car in the switching queue as the car progresses through the switching queue toward the switch, the computation of a car switching solution including a selection of a classification track among the plurality of the classification tracks in which the car is to be switched;
c) releasing at the output of the data processing apparatus data conveying at least one of the computed switching solutions.
2. A method for computing car switching solutions as defined in claim 1, including computing with the data processing apparatus an expected switch time for the at least one car, the expected switch time being indicative of an approximate time at which the at least one car is expected at the switch, the data processing apparatus using the computed expected switch time as a factor during the computation of at least one switching solution for the at least one car.
3. A method as defined in claim 1, wherein the at least one car belongs to a train block, the method including computing with the data processing apparatus available space in several classification tracks of the plurality of classification tracks to receive cars that belong to the train block.
4. A method as defined in claim 3, including computing at least one of the car switching solutions with the data processing apparatus by using the computed available space as a factor.
5. A method as defined in claim 3, wherein the data designating a classification track among the plurality of classification tracks for which the data processing apparatus has computed that available space exists to receive all the cars of the train block.
6. A method for computing railcar switching solutions as defined in claim 1, wherein the data is a first data and the at least one car belongs to a train block, the method including receiving at an input of the data processing apparatus second data indicative of an ETA at the railway switchyard of one or more cars of the train block, the method including processing the second data with the data processing apparatus under control of the software in computing one or more of the car switching solutions for the at least one car.
7. A method as defined in claim 1, wherein the at least one car belongs to a first train block, the method including computing with the data processing apparatus a car switching solution for the at feast one car that locates the at least one car in a classification track containing cars that belong to a second train block, wherein the first train block and the second train block belong to different departure trains.
8. A method as defined in claim 3, wherein the data processing apparatus includes an input, wherein the data is a first data and wherein the train block is a first train block, the method including:
a) providing at the input second data indicative of a pull time of a second train block in a first classification track of the plurality of classification tracks;
b) processing with the data processing apparatus under control of the software the second data to determine available space in the first classification track.
9. A method as defined in claim 8, wherein the pull time is indicative of a time at which the second train block is expected to vacate the first classification track.
10. A method as defined in claim 1, wherein the data processing apparatus includes an input, wherein the data is a first data and wherein the at least one car belongs to a first train block, the method including:
a) providing at the input second data indicative of an arrival profile of a second train block;
b) processing with the data processing apparatus under control of the software the second data to compute or more of the switching solutions of the at least one car.
11. A method as defined in claim 2, including re-computing with the data processing apparatus an expected switch time for the at least one car at each computation of a switching solution for the at least one car.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of providing a desired constant AC voltage to a variable load which is arranged remote of a voltage source, comprising the steps of:
compensating for a voltage drop over an electrical supply line which connects the load to the voltage source by a compensation AC voltage, the compensation AC voltage being added to the desired constant AC voltage to determine an output AC voltage of the voltage source;
connecting an ohmic load instead of the variable load via the supply line to the AC voltage source and measuring a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of an AC voltage |Uload| drop over the ohmic load, and a total value of the alternating current |I| which is conducted at that same time;
determining a first constant CR from the measured values for the linear variation of the compensation AC voltage with the total value of the alternating current and cos(phi) from the measured values;
once the constant CR has been determined, connecting the variable load instead of the ohmic load via the supply line to the AC voltage source; and
varying the compensation AC voltage depending both on an absolute value of an alternating current conducted to the load and on a phase angle phi between the output AC voltage of the voltage source and the alternating current, wherein the step of varying the compensation AC voltage depending both on the absolute value of the alternating current conducted to the load and on the phase angle phi comprises the step of calculating the compensation AC voltage from two summands which are linearly dependent on the total value of the alternating current, and one of which additionally comprises the factor CR* cos(phi) and the other of which is additionally linearly dependent on sin(phi).
2. The method of claim 1, wherein the constant CR is determined as (|Ufull|\u2212|Uload|)|I|.
3. The method of claim 1, further comprising the steps of connecting a mixed ohmic and inductive load instead of the variable load via the supply line to the AC voltage source, measuring a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of the AC voltage |Uload| dropping over the ohmic component of the mixed ohmic and inductive load, a total value of the current |I| conducted at the same time, and the phase angle phi, and determining a second constant CL for the linear variation of the compensation AC voltage with the total value of the alternating current and sin(phi) from the measured values.
4. The method of claim 1, further comprising the steps of:
supplying the output AC voltage to the variable load;
measuring a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of the AC voltage |Uload| dropping over an ohmic component of the variable load, a total value of the current |I| conducted at the same time, and the phase angel phi; and
determining a second constant CL for the linear variation of the compensation AC voltage with the total value of the alternating current and sin(phi) from the measured values.
5. The method of claim 3, wherein the constant CL is determined as |Ufull|\u2212|Uload|\u2212CR* |I|* cos(phi)|I|* sin(phi).
6. The method of claim 3, wherein the constant CL is determined at a value of |Uload| which is equal to the desired constant AC voltage.
7. The method of claim 6, wherein the constant CR is determined at a value of |Uload| which is equal to the desired constant AC voltage.
8. The method of claim 6, wherein the constants CR and CL are at first approximated at a value of |Uload| which is equal to the desired constant AC voltage, and then a value of |Uload| which is equal to the desired constant AC voltage is approached with the approximated values of CR and CL.
9. A method of providing a desired constant AC voltage to a variable load which is arranged remote of a voltage source, comprising the steps of:
compensating for a voltage drop over an electrical supply line which connects the load to the voltage source by a compensation AC voltage, the compensation AC voltage being added to the desired constant AC voltage to determine an output AC voltage of the voltage source; and
varying the compensation AC voltage depending both on an absolute value of an alternating current conducted to the load and on a phase angle phi between the output AC voltage of the voltage source and the alternating current,
wherein the voltage source is a rotating frequency converter, and further comprising the step of varying an exciting power of a generator to achieve a variation of the compensation AC voltage.
10. The method of claim 1, wherein the voltage source is selected from a static frequency converter and an electronically controlled transformer, and further comprising the step of separately varying the compensation AC voltage for each phase of the output AC voltage of the voltage source.
11. A method of providing a desired constant AC voltage having a frequency at least 200 Hz to an airplane which is positioned on the ground remote of a voltage source and which is connected to the voltage source via a supply line, comprising the steps of:
connecting an ohmic load via the supply line to the AC voltage source, measuring a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of an AC voltage |Uload| dropping over the ohmic load, and a total value of the alternating current |I| which is conducted at that same time;
determining a first constant CR as (|Ufull|\u2212|Uload|)|I|;
connecting a mixed ohmic and inductive load via the supply line to the AC voltage source, measuring a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of the AC voltage |Uload| dropping over the ohmic load, a total value of the current |I| conducted at the same time, and the phase angle phi;
determining a second constant CL as |Ufull|\u2212|Uload|\u2212CR* |I|* cos(phi)|I|* sin(phi);
connecting the airplane via the supply line to the voltage source; and
repeatedly calculating a compensation AC voltage as |I|*CR*cos(phi)+ |I|*CL*sin(phi) and adding the compensation AC voltage to the desired constant AC voltage to determine an output AC voltage of the voltage source, |I| being the total value of the actual alternating current conducted from the voltage source to the airplane and phi being the actual phase angle between the output AC voltage of the voltage source and the alternating current conducted from the voltage source to the airplane.
12. The method of claim 11, further comprising the steps of:
connecting another airplane via the supply line to the voltage source;
repeatedly calculating a compensation AC voltage as |I|*CR*cos(phi)+|I|*CL*sin(phi) and adding the compensation AC voltage to the desired constant AC voltage to determine an output AC voltage of the voltage source, |I| being the total value of the actual alternating current conducted from the voltage source to the other airplane and phi being the actual phase angle between the output AC voltage of the voltage source and the alternating current conducted from the voltage source to the other airplane.
13. A system for providing a desired constant AC voltage to a variable load which is arranged remote of a voltage source, comprising:
means for compensating for a voltage drop over an electrical supply line which connects the load to the voltage source by a compensation AC voltage, the compensation AC voltage being added to the desired constant AC voltage to determine an output AC voltage of the voltage source;
means for measuring, once an ohmic load is connected instead of the variable load via the supply line to the AC voltage source, a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of an AC voltage |Uload| drop over the ohmic load, and a total value of the alternating current |I| which is conducted at that same time;
means for determining a first constant CR from the measured values for the linear variation of the compensation AC voltage with the total value of the alternating current and cos(phi) from the measured values;
means for varying, once the variable load is connected instead of the ohmic load via the supply line to the AC voltage source, the compensation AC voltage depending both on an absolute value of an alternating current conducted to the load and on a phase angle phi between the output AC voltage of the voltage source and the alternating current, wherein the means for varying the compensation AC voltage depending both on the absolute value of the alternating current conducted to the load and on the phase angle phi comprises means for calculating the compensation AC voltage from two summands which are linearly dependent on the total value of the alternating current, and one of which is additionally comprises the factor CR* cos(phi) and the other of which is additionally linearly dependent on sin(phi).
14. The system of claim 13, wherein the constant CR is determined as (|Ufull|\u2212|Uload|)|I|.
15. The system of claim 13, further comprising means for connecting a mixed ohmic and inductive load instead of the variable load via the supply line to the AC voltage source, means for measuring a total value of the output AC voltage |Ufull| provided by the voltage source, a total value of the AC voltage | Uload| dropping over the ohmic component of the mixed ohmic and inductive load, a total value of the current |I| conducted at the same time, and the phase angle phi, and means for determining a second constant CL for the linear variation of the compensation AC voltage with the total value of the alternating current and sin(phi) from the measured values.
16. The system of claim 13, further comprising means for measuring a total value of the output AC voltage |Ufull| provided by the voltage source to the variable load, a total value of the AC voltage |Uload| dropping over an ohmic component of the variable load, a total value of the current |I| conducted at the same time, and the phase angel phi, and means for determining a second constant CL for the linear variation of the compensation AC voltage with a total value of the alternating current and sin(phi) from the measured values.
17. The system of claim 15, wherein the constant CL is determined as |Ufull|\u2212|Uload|\u2212CR* |I|* cos(phi)|I|* sin(phi).
18. The system of claim 15, wherein the constant CL is determined at a value of |Uload| which is equal to the desired constant AC voltage.
19. The system of claim 18, wherein the constant CR is determined at a value of |Uload| which is equal to the desired constant AC voltage.
20. The system of claim 18, wherein the constants CR and CL are at first approximated at a value of |Ufull| which is equal to the desired constant AC voltage, and then a value of |Uload| which is equal to the desired constant AC voltage is approached with the approximated values of CR and CL.
21. The method of claim 4, wherein the constant CL is determined as |Ufull|\u2212|Uload|\u2212CR*|I|* cos(phi)|I|* sin(phi).
22. The system of claim 16, wherein the constant CL is determined as |Ufull|\u2212|Uload|\u2212CR*|I|* cos(phi)|I|* sin(phi).