外文翻译---预测铁路供电系统工作模式的方法和工具(编辑修改稿)

外文翻译---预测铁路供电系统工作模式的方法和工具(编辑修改稿)内容摘要：

utes) Number of cargo trains in a pack Cargo Passenger Up to 24 Up to 20 20 2 More than 20 15 3 2436 Up to20 12 4 More than 20 10 6 3748 Up to 20 9 5 More than 20 8 7 4972 Up to 20 8 7 More than 20 6 10 More than 72 Up to 20 7 8 More than 20 5 12 Table 1: Determining the number of cargo trains and the time interval 7 between subsequent trains in a pack. Additionally, the model takes care of: * different ordering of average cargo trains and heavy cargo trains * displacement interval (the time difference between arrival on the inter substation zone of trains from one direction and the other) * feeder length (the length of the feeding wire which connects railway substation with traction work) It is worth mentioning that some railway sections place substations on some distance from the railway. If the length of the feeders is long enough to influence the voltage on the lootive, this should be taken into account. It is also possible to have one railway substation placed at a distance with a feeder length of several kilometres, while the other one is placed directly on a railway. This leads to the currents of the substation with a shorter feeder length to be always greater than the currents of the substation with a longer feeder. In order to pensate the currents it is possible to artificially increase the length of a feeder on the substation which is too close to the railway (Figure 3). Figure 3: Artificial increase in feeder length. Taking all section peculiarities into account is a distinct feature of our model: it also allows to change the length and resistance of a feeder. In order to pletely simulate trains moving on a real life railway section, the model utilises data about points where the trains ing from 8 different directions can pass by each other. During simulation railway substation currents and voltage losses are calculated every minute. Later their maximums are determined and produced. Modelling the breakdown mode If one of the railway substations goes down, it plicates the situation for power supply system significantly. The main goal is then to not let breakdown mode bee emergency mode. The biggest plication is that in AC systems the inter substation zone can only be fed from one side (Figure 4)adjacent inter substation zones are fed from different phases. Figure 4: Switching to onesided feeding when one railway substation is down. When one substation falls off, it can also result in a brief break in train traffic. Trains in this case can be accumulated at one of the stations. In order to repair this omission when the traffic is restored, the trains are sent with minimum possible gaps. This mode is called full use of carrying capacity of a railway section. Thus, on design stage heating of the traction wire should be checked in two conditions: * separate feeding of tracks on double track zones * train traffic with minimal time intervals between trains Apparently, the currents of two adjacent railway substations rise significantly when onesided feeding scheme is launched. Yet it should be 9 impossible for these currents to hit the maximum limit, otherwise the traction work wire will experience a breach in mechanical durability. Increase of currents in traction work not only plicates power supply system working conditions, but also causes high electromagic impact on munication lines located close to the railway. The voltage losses increase, too. It makes sense to assume that the minimal voltage level in traction work will be experienced in proximity of the switched off substation (at the end of console feeding zone). Uncontrolled drop in voltage level can lead to disconnection of lootives. Therefore it is particularly important to predict how the power supply system will operate in the breakdown mode. A breakdown mode cannot hold on for long (it usually takes up to several hours). It is possible to limit the number of trains moving inside the inter substation zone and to increase time intervals between train。