CN206977054U - A kind of electric railway energy-storage power supplying apparatus - Google Patents

Abstract

The utility model provides an electrified railway energy storage power supply device, which relates to the field of electrified railway traction power supply. The traction incoming line is connected to the traction busbar; the traction busbar is connected to the traction network through the feeder to supply power to the train; the primary side of the coupling transformer is connected to the traction busbar and ground, and the secondary side is connected to the AC port of the AC-DC converter; the DC port of the AC-DC converter is connected to the energy storage device; The measurement and control unit is connected with the voltage transformer, the measurement terminal of the current transformer and the control terminal of the AC-DC converter. With load peak shaving as the goal, select the reference value ≥ load average value; the maximum power of the accumulator = the maximum value of the peak in the past, the capacity of the accumulator = the area of the peak with the largest area in the past; when the traction load power < the reference value, Put the AC-DC converter in the rectification condition and charge the accumulator; when the traction load power is greater than the reference value, put the AC-DC converter in the inverter condition, discharge the accumulator, and feed the inverted AC power into the Traction bus. It is used for peak-shaving power supply and negative sequence control of electrified railways.

Description

An electrified railway energy storage power supply device

technical field

The utility model relates to the field of electrified railway traction power supply, in particular to the management and control technology of electrified railway traction load shifting and filling valleys.

Background technique

Peak shaving and valley filling are important measures for power system load management. For the power grid, peak shaving is conducive to improving the utilization rate of power transmission and transformation equipment, saving equipment expansion and updating costs, and reducing power supply costs. For ordinary users, it can use The peak-to-valley price difference achieves the economic benefit of reducing electricity bills. The energy storage system has the dual functions of electric energy storage and release, that is, it has the dual functions of load shaving and valley filling. Among them, the battery energy storage system, the supercapacitor energy storage system and its hybrid energy storage system have unique advantages. It plays an irreplaceable and huge role, and is playing an increasingly important role.

Electrified railways are a large number of industrial users, and have distinctive characteristics, such as the traction load fluctuates violently, and the peak value of traction load power is the key: it not only causes power quality problems mainly caused by negative sequence technically, but also directly affects user benefits economically. Because the peak load is closely related to the main transformer capacity billing and the maximum demand billing in the two-part electricity price, railway users will pay extra costs. Therefore, peak shaving-reducing load peak has the opportunity of both technical and economic advantages: it can not only control the negative sequence and reduce adverse effects, but also obtain benefits in the implementation of the two-part electricity price, that is, either reduce the maximum demand to obtain benefits, or reduce the main transformer Capacity and then reduce fixed capacity charges to achieve benefits.

The Chinese patent discloses "Electrified Railway Traction Power Supply Energy Storage Device and Its Method (201410002241.X)", the purpose of which is to "fully recover the electric energy fed back by the locomotive braking, improve the energy utilization rate of the traction power supply system, and reduce the installed capacity of the traction transformer and billing capacity, cost saving.” But, the problem that this technical scheme exists is: (1) when active current Ip＜0, carry out the criterion of energy storage (see its claim 5 and accompanying drawing 5) existence incorrect situation. Because train electrical braking does not happen to every power supply arm. For example, the Beijing-Shanghai high-speed railway has a total length of 1318km, 24 stations, and 27 substations (54 power supply arms). The average distance between stations (about 55km) is much greater than the average length of power supply arms (about 24.4km). The vehicle (electrical) braking occurs when the station is stopped. Obviously, because there is a high probability of no power supply arm at the station, then the probability of no electric braking is high, or even if the braking occurs, its regenerative power is used by the same traction train If the electric braking power is not absorbed by the same train, the criterion in this case will not occur; furthermore, even if the electric braking power is not absorbed by the same train, it will It returns to the grid without adding any equipment, which is the most direct and economical, and is also encouraged by the state for energy conservation and emission reduction (just like household photovoltaic power generation). This patent specifically sets the energy storage device when the power current Ip<0 Energy storage is also unnecessary. (2) The patent's criterion method of "total current I _s > rated current I _e of the connected power supply arm" (see claim 7) is also incorrect. Taking the Beijing-Shanghai high-speed railway as an example, the operating main transformer (rated) capacity of each traction substation is 100 (2×50) MVA, and the maximum power is only less than 70 MVA. According to the patent criterion, there are only valleys and no peaks, which cuts Peak conditions will never occur, and its energy storage device will never work. Even on other lines, also because there is a power supply arm that does not cause electrical braking, then at this time, the energy storage obtained by the criterion of "active current Ip<0" = 0, if "total current I _s > connected power supply In the case of the rated current I _e ” of the arm, there is no power available for peak clipping. In fact, the installation capacity of the traction transformer corresponding to the rated current I _e of the power supply arm is determined at the design stage. Once determined, it has nothing to do with the actual traction load, that is, the traction transformer is either under-loaded or overloaded, which is useless . Therefore, the said "total current I _s > rated current I _e of the connected power supply arm" is not advisable. In short, this technical solution has the failure of energy storage and peak shaving. At this time, it is impossible to "reduce the installed capacity and billing capacity of the traction transformer, and save costs", let alone realize real-time peak shaving under all working conditions. Valley filling optimization.

Noticing the technical and economic importance of electrified railway traction load shaving and filling valleys, and more attention should be paid to the characteristics of electrified railway operation chart in daily units, that is, fixed and accurate periodicity, so useful information can be extracted from it. Significant statistical values are studied and utilized. The technical problem to be solved now is: how to achieve real-time optimal peak shaving, reduce transformer capacity or maximum demand, and achieve the best economic benefits through special equipment and methods according to the characteristics of the traction load, and at the same time control the negative sequence and improve technical performance .

Utility model content

The purpose of this utility model is to provide an electrified railway energy storage and power supply device, which can effectively solve the technical problem of traction load real-time optimal peak-shaving equipment, in order to reduce the capacity of the main transformer or the maximum demand, and obtain the best economic benefits. At the same time, the negative sequence is managed and the technical performance is improved.

The purpose of this utility model is achieved through the following technical solutions: an electrified railway energy storage power supply device, including a coupling transformer, an AC-DC converter, a voltage transformer, a current transformer and a measurement and control unit; the traction incoming line is connected to the traction busbar; The traction bus is connected to the traction network through the feeder to supply power to the train; the voltage transformer measures the ground voltage of the traction bus; the current transformer measures the traction load of the feeder; the primary side of the coupling transformer is connected to the traction bus and ground, and the secondary side is connected to the AC port of the AC-DC converter The DC port of the AC-DC converter is connected to the energy storage; the measuring end of the voltage transformer and the measuring end of the current transformer are connected to the input interface of the measurement and control unit, and the output interface of the measurement and control unit is connected to the control terminal of the AC-DC converter.

The purpose of this utility model is achieved by the following control methods: the measurement and control unit obtains the traction load power through the voltage transformer and the current transformer, records the traction load power curve under normal working conditions in the past, calculates its average value, and counts the maximum value in the past; Load peak shaving is the target, select: target, select: average ≤ reference value < maximum value; the load power curve higher than the reference value is the peak, and the load power curve lower than the reference value is the valley; the maximum power of the energy storage (kW ) = the maximum value of the peak in the past (kW), the capacity of the accumulator (kWh) = the area of the peak with the largest area in the past (kWh); when the traction load power < the reference value, the measurement and control unit controls the AC-DC converter to rectify At this time, the rectified charging power = the difference between the reference value and the traction load power at this time; when the traction load power > reference value, the measurement and control unit controls the inverter of the AC-DC converter to discharge the accumulator, and the inverter The final alternating current is fed into the traction bus, and the power of the discharge inverter at this time = the difference between the current traction load power and the reference value; when the traction load power = the reference value, the measurement and control unit controls the AC-DC converter to stand by.

Considering that the traction load fluctuations are characterized by violent fluctuations and frequent peak-to-valley alternation, the accumulator is required to have a high number of charging and discharging cycles to ensure a long service life. Therefore, supercapacitors should be given priority for energy storage.

The working principle of the utility model is: the traction load of the electrified railway fluctuates violently, and many technical and economic problems appear along with the peak value of the traction load: economically, the peak value of the load is related to the main transformer capacity billing and the maximum demand in the two-part electricity price. It is closely related to volume billing. Peak shaving—reducing the peak load can reduce electricity charges and obtain economic benefits, that is, to obtain benefits by reducing the maximum demand, or reduce the capacity of the main transformer and then reduce the fixed capacity charge to obtain benefits; technically, the peak load causes electric energy Quality issues have attracted much attention. For example, due to the prominent power quality problems mainly caused by voltage unbalance due to negative sequence, the two limit values of voltage unbalance in the national standard (see GB/T15543-2008 Power Quality Three-phase Voltage Unbalance Balance) is formulated for the peak load and the maximum value of 95% probability, so peak shaving - reducing the peak load can also control the negative sequence and improve technical performance; The average value of the traction load under normal working conditions has good stability and accuracy; record the power curve of the traction load under normal working conditions in the past, calculate its average value, and count the maximum value in the past; selection: average value ≤ reference value < maximum value; definition: The load power curve greater than the reference value is a peak, and the load power curve less than or equal to the reference value is a valley; within a specified period of time, when the reference value = average value, the integral (area) of all peaks = the integral (area) of all valleys, when When the reference value is greater than the average value, the integral (area) of all peaks < the integral (area) of all valleys; the maximum power of the accumulator = the maximum value of the peak in the past, and the capacity of the selected accumulator = the area of the peak with the largest area in the past; Comparing the traction load power with the reference value can control the charging and discharging conditions of the accumulator in real time, and realize real-time peak shaving and valley filling; compared with the average value, the larger the reference value, the fewer the number of peaks and the fewer the number of charge and discharge , the smaller the capacity of the energy storage, the less the investment, but the smaller the effect of peak shaving, and the lower the electricity cost, and vice versa; therefore, a technical and economical optimal solution can be sought through the selection of the benchmark value.

Compared with the prior art, the beneficial effects of the utility model are:

1. The operating diagram of electrified railways is based on the day and has a strong periodicity. Under normal working conditions in the past, the average value of the traction load and the reference value greater than the average value have good stability and accuracy. Based on this, the minimum energy storage can be used Real-time peak shaving can be realized by using the device capacity.

2. Taking peak shaving as the goal, the capacity of the main transformer or the maximum demand can be reduced through the selection of the reference value, and the best economic benefits can be obtained. At the same time, the negative sequence can be controlled and the technical performance can be improved.

Three, advanced technology, easy to implement.

Description of drawings

Fig. 1 is a schematic structural view of an embodiment of the utility model.

Fig. 2 is a schematic diagram of the peak shaving process of the embodiment of the utility model.

Detailed ways

Example

Below in conjunction with accompanying drawing, the utility model is further described:

Figure 1 shows that a specific embodiment of the present invention is: an electrified railway energy storage power supply device, including a coupling transformer 1, an AC-DC converter 2, an energy storage device 3, a voltage transformer 4, and a current transformer 5 And the measurement and control unit 6; Take the high-speed rail traction substation as an example, wherein the single-phase connection main transformer secondary side leads the traction incoming line 7, and the traction incoming line 7 is connected to the traction busbar 8; the traction busbar is connected to the traction network through the feeder line 9 to supply power to the train; The transformer 5 measures the voltage of the traction bus 8 to ground; the current transformer 5 measures the traction load of the feeder 9; the primary side of the coupling transformer 1 is connected to the traction bus 8 and the ground, and the secondary side is connected to the AC port of the AC-DC converter 2; the AC-DC converter The DC port of 2 is connected to the energy storage device 3; the measuring terminal of the voltage transformer 4 and the measuring terminal of the current transformer 5 are connected to the input interface of the measurement and control unit 6, and the output interface of the measurement and control unit 6 is connected to the control terminal of the AC-DC converter 2.

The measurement and control unit 6 obtains the traction load power through the voltage transformer 4 and the current transformer 5, records the traction load power curve under normal working conditions in the past (such as the 7th), calculates its average value, and counts the maximum value of the traction load in the past (such as the 7th) ;Aiming at load peak shaving, select: average value ≤ reference value < maximum value; the load power curve higher than the reference value is the peak, and the load power curve lower than the reference value is the valley; the maximum power of the accumulator 3 = the previous peak The maximum value of , the capacity of accumulator 3 = the area of the peak with the largest area in the past; take the time t step length △ (s), when the traction load power at time t < the reference value, the measurement and control unit 6 controls the AC-DC converter 2 Rectify to charge the accumulator 3, the rectified and charged power at this time = the difference between the reference value and the traction load power at this time; when the traction load power > reference value, the measurement and control unit 6 controls the AC-DC converter 2 to invert, so that the energy storage Discharger 3 discharges, and feeds the alternating current after inversion into the traction bus 8, and the power of discharge inverter at this time=the difference between the traction load power and the reference value at this time; when the traction load power=the reference value, the measurement and control unit 6 controls the AC-DC The streamer 2 is on standby; so the cycle is taken as a unit of day.

Fig. 2 is a schematic diagram of the peak-shaving process of the embodiment, in which the curve 10 is the actual measured load power of the actual feeder 9, the positive one represents the traction (power consumption) working condition, the negative one represents the braking regeneration (power generation) working condition, and the abscissa is min, the ordinate is MW. Record the traction load power curve under normal working conditions in the past, and calculate its average value 11; select a load power curve for a time period (1h) in the figure, take load peak shaving as the goal, and select the reference value 13 > reference value 12 > average value 11; The load power curve of the reference value is a peak, and the load power curve lower than the reference value is a valley; the maximum power of the accumulator 3 = the maximum value of the peak in the past, and the capacity of the accumulator 3 = the area of the peak with the largest area in the past; when When the traction load power<reference value, the measurement and control unit 6 controls the AC-DC converter 2 to rectify and charge the accumulator 3. At this time, the rectified charging power=the difference between the reference value and the traction load power at this time; when the traction load power>reference value , the measurement and control unit 6 controls the inverter of the AC-DC converter 2 to discharge the accumulator 3, and feeds the inverted AC power into the traction bus 8. At this time, the power of the discharged inverter = the difference between the traction load power and the reference value at this time Poor; when traction load power = reference value, the measurement and control unit 6 controls the AC-DC converter 2 to stand by.

Obviously, by comparing the traction load power with the reference value, the charging and discharging conditions of the accumulator 3 can be controlled in real time to realize real-time peak shaving and valley filling; the larger the reference value is, if the reference value 13 is selected to be greater than the reference value 12, the number of peaks will increase. The less the charge and discharge times, the smaller the capacity of the accumulator 3, and the smaller the investment, but the weaker the peak-cutting ability, the less the electricity bill will be reduced, and vice versa; A technical and economical optimal solution.

It can be seen from the working principle that the energy storage and power supply device for electrified railways and its control method as well as the definitions of average value, reference value, peak and valley are also suitable for including regenerative conditions, ie traction load power<0.

Considering that the traction load fluctuations are characterized by violent fluctuations and frequent peaks and valleys, the accumulator 3 is required to have a high number of charge and discharge cycles to ensure a long service life. Therefore, supercapacitors should be given priority as energy storage devices.

Claims (1)

1. An electrified railway energy storage power supply device, comprising a coupling transformer (1), an AC-DC converter (2), a voltage transformer (4), a current transformer (5); the traction incoming line (7) is connected to the traction busbar ( 8); the traction busbar (8) is connected to the traction network through the feeder (9) to supply power to the train; the voltage transformer (4) measures the ground voltage of the traction busbar (8); the current transformer (5) measures the traction load of the feeder line (9) , it is characterized in that: the primary side of the coupling transformer (1) is connected to the traction busbar (8) and ground, and the secondary side is connected to the AC port of the AC-DC converter (2); the DC port of the AC-DC converter (2) is connected to the energy storage device ( 3) connection; the measuring end of the voltage transformer (4) and the measuring end of the current transformer (5) are connected to the input interface of the measurement and control unit (6), and the output interface of the measurement and control unit (6) is connected to the AC-DC converter (2) The control terminal is connected.