Double-power-station power distribution load balancing control method

Abstract

The invention relates to the technical field of ship power systems, in particular to a double-power-station power distribution load balancing control method. Through cooperation of the steps of double-power-station load balancing judgment, load switching priority classification, power distribution network reconstruction objective function and parameter setting, minimum switching action frequency and corresponding load switching calculation, load power supply switching operation and the like, load power supply switching can be accurately controlled according to the real-time operation condition of a ship power grid. Load balancing control of double power stations is realized; function calculation is carried out through software, a result is output, personal judgment and decision of operators are not depended on in the double-power-station power distribution load balancing control operation process, and a switch needing switching control can be accurately calculated through a preset target function and parameters; according to the method, the difference condition of different loads is considered, in the process of controlling the change-over switch, the influence range of power failure can be effectively reduced, the possibility of short-time power loss of important loads can be reduced to the maximum extent, and the performance of a ship power distribution system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ship power systems, and in particular to a dual-station power distribution load balancing control method. Background Art

[0002] According to relevant design specifications and actual mission requirements, medium and large surface ships and some special mission ships need to be equipped with two or more main power stations. Taking the most common setting of two main power stations in front and behind as an example, it is generally required that the configurations of the two power stations are basically the same, and one power station can meet the power supply needs of all loads on the entire ship or at least all important loads; the two power stations are connected by jumper wires to form a unified power distribution network for the entire ship; the main loads are equipped with two power supply lines, which are respectively powered by the front and rear power stations, and the power supply switching has two modes: power outage switching and non-power outage switching. In order to save overall resources as much as possible, the rated current of the jumper wire is generally limited and will not be designed according to the maximum power of the entire ship. In most cases, it is equivalent to the rated current of a single generator.

[0003] From the perspective of practical use, in order to avoid overloading of the jumper wire and power outage of the entire ship in the event of a single power station failure, the loads of the two power stations are required to be as balanced as possible. The existing technology of power distribution load balancing control of dual-power station ships is usually manually observed and judged by operators. When to control and which switches to switch all depend on the operator's experience and personal judgment, which requires high ability and quality of the operator, and it is difficult to ensure that the impact of power outage is minimized during the process of controlling the switching of switches. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a dual-power station power distribution load balancing control method, which can accurately control the load power supply switching according to the real-time operation status of the ship's power grid, realize load balancing control of the dual power stations, and minimize the possibility of short-term power failure of important loads, thereby improving the performance of the ship's power distribution system.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A dual-station power distribution load balancing control method comprises the following steps:

[0007] S1, dual power station load balance judgment: calculate the power difference value of the two power stations, when the difference value is not greater than the set value, judge that the two power stations are in a load balance state, when the difference value is greater than the set value, judge that the two power stations are in a load non-balanced state, and execute subsequent steps;

[0008] S2, load switching priority classification: according to whether there is a power outage during the load power supply switching process, the importance of the load, and the impact of a short-term power outage on the load, the power supply switching priority of each load on the ship is set;

[0009] S3, setting the distribution network reconstruction objective function and parameters;

[0010] S4, calculating the minimum number of switch actions and the corresponding load switch: calculating the load circuit breaker operation number value corresponding to the minimum value of the distribution network reconstruction objective function, and recording the corresponding load circuit breaker;

[0011] S5, operate the load power supply switching: after the operator cuts off the corresponding load circuit breaker on the main distribution board corresponding to the power station with a larger load, the two power conversion devices are automatically operated to switch the load power supply to the main distribution board corresponding to the power station with a smaller load, thereby completing the load power supply switching.

[0012] Furthermore, in step S1, the current total power P of the two power stations is read through the power distribution monitoring device. for , P aft , and calculate the power difference between the two power stations ΔP=|P for -P aft |; When the power difference value ΔP is greater than the set value, the subsequent steps are continued.

[0013] Furthermore, in step S2, setting the power supply switching priority of each load on the ship specifically includes:

[0014] Classify the equipment in the ship's propulsion system and mission function system that is not allowed to be powered off during navigation as a priority load;

[0015] The equipment in the ship's propulsion system and mission function system that can lose power for a short time during navigation is divided into the second category of priority loads;

[0016] Divide the ship's other non-propulsion systems and mission function system-related equipment into three priority loads;

[0017] The load with a higher power supply switching priority has a higher priority in switching when the power supply of the dual power station loads is switched.

[0018] Furthermore, in step S3, the parameters related to the distribution network reconstruction objective function include: the power difference between the two power stations, the number of load circuit breaker operations on the main distribution board, the cost weight of the load circuit breaker operation on the main distribution board, the load weight of the corresponding power supply equipment, the power of the corresponding power supply equipment and the power outage mark.

[0019] Furthermore, in step S3, the distribution network reconstruction objective function is as follows:

[0020]

[0021] Where P for is the current total power of the former power station;

[0022] P aft is the current total power of the rear power station;

[0023] T is the number of operations of the load circuit breaker on the main distribution board;

[0024] P iavr is the cost weight of the load circuit breaker action, which is generally 10kW, 20kW, etc.

[0025] λ i The load weight of the power supply equipment corresponding to the load circuit breaker is selected according to the importance level;

[0026] P i is the power of the corresponding power supply equipment;

[0027] K i It is the power-off mark. If the load has two power supplies that are switched without power outage, K i =0, if it is a power failure conversion, then K i =1.

[0028] Furthermore, in step S4, the calculation of the minimum number of switch actions specifically includes:

[0029] 1) According to the power supply switching priority of each load and the size of the distribution power, the load circuit breakers on the main distribution board corresponding to the power station with a larger load are sorted to form a search table;

[0030] 2) Based on the search table, calculate the objective function value corresponding to each load circuit breaker in sequence starting from the table head;

[0031] 3) Determine the value of the number of operations T of the load circuit breaker on the main distribution board corresponding to the minimum value of the objective function.

[0032] The step of sorting the load circuit breakers on the main switchboard corresponding to the power station with a larger load specifically includes:

[0033] First, the loads are sorted according to their power supply switching priorities, and arranged in a search table from front to back according to their power supply switching priorities;

[0034] Then, for loads with the same power supply switching priority, they are sorted according to the size of the distribution power and arranged in the search table from large to small according to the distribution power;

[0035] Finally, the device that can realize the non-stop switching of two power supplies is placed at the meter head.

[0036] Further, in step S5, the corresponding load circuit breaker is specifically: based on the search table, the corresponding load circuit breaker when the objective function value is minimum and all load circuit breakers arranged before the load circuit breaker in the search table are calculated.

[0037] Furthermore, in step S5, when the corresponding load circuit breakers are all cut off, the two power conversion devices automatically operate to switch the corresponding loads to the main distribution board corresponding to the power station with smaller load, so as to realize load balancing control of the dual power station distribution.

[0038] Compared with the prior art, the present invention has the following main advantages:

[0039] 1. The present invention can accurately control the load power supply switching according to the real-time operation of the ship power grid and realize the load balancing control of the dual power stations through the steps of load balancing judgment of the dual power stations, load switching priority classification, setting the distribution network reconstruction objective function and parameters, calculating the minimum number of switch actions and the corresponding load switch, and operating the load power supply switching;

[0040] 2. The present invention uses software to solve functions and output results. In the process of load balancing control of dual power station distribution, it does not rely on the personal judgment and decision of the operator. By presetting the objective function and parameters, the switch required for switching control can be accurately calculated;

[0041] 3. The present invention takes into account the differences between different loads. In the process of controlling the switching switch, it can effectively reduce the impact range of power outages, minimize the possibility of short-term power outages of important loads, and improve the performance of the ship's power distribution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flow chart of a dual-station power distribution load balancing control method in Embodiment 1 of the present invention;

[0043] Figure 2 This is a topological diagram of the dual-power station ship power distribution network in the second embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0046] Embodiment 1: This embodiment provides a dual-station power distribution load balancing control method, such as Figure 1 As shown, it mainly includes the following steps:

[0047] S1, Dual power station load balancing judgment:

[0048] The power difference between the two power plants is calculated, and when the difference is greater than a set value, the algorithm is started. The set value can be set as needed, and can be set to a fixed power value, a percentage of the rated power of the power plant or unit, a percentage of the current operating power capacity, and other forms.

[0049] S2, load switching priority classification:

[0050] The switching priority is set after comprehensive consideration of factors such as whether there is a power outage during the load power supply switching process, the importance of the load, the impact of short-term power outages, etc. When the two power supplies of the load are switched without power outage, its priority is higher, that is, it is switched first under the same conditions; when the load is more important or the impact of power outage is greater, its priority is lower, and multiple priority levels can be set according to their different degrees.

[0051] S3, setting the distribution network reconstruction objective function and parameters:

[0052] The parameters of the distribution network reconstruction objective function mainly include the load difference between the two power stations, the number of load circuit breaker operations, the load circuit breaker operation weight, the power supply equipment load weight, the power consumption of the power supply equipment, the power outage mark, etc.

[0053] The distribution network reconstruction objective function determined by the present invention is as follows:

[0054]

[0055] Among them, P for is the total load power of the former power station;

[0056] P aft is the total load power of the rear power station;

[0057] T is the number of operations of the load circuit breaker on the low-voltage main distribution board;

[0058] P iavr The cost weight of the load circuit breaker action on the main distribution board, usually 10kW, 20kW, etc.

[0059] λ i The load weight of the corresponding power supply equipment is selected according to the importance, such as 1 / 3, 1 / 2, 1 or 0.3, 0.8, 1, etc.;

[0060] P i The power of the corresponding power supply equipment;

[0061] K iIt is the power-off mark. If the load has two power supplies that are switched without power outage, K i =0, if it is a power failure conversion, then K i =1.

[0062] At the same time, the total power limit of the power station is used as a constraint condition, that is, the total power of all loads connected to this power station must not exceed the total available capacity of this power station.

[0063] S4, calculate the minimum number of switch actions and the corresponding load switch:

[0064] In order to reduce the amount of objective function calculation and improve calculation efficiency, the load circuit breakers are prioritized; the ranking is based on factors such as load type and working current size;

[0065] Based on the objective function solution, the minimum number of switching actions and the corresponding load switch are obtained.

[0066] Specifically, based on the objective function and parameters, in order to reduce the amount of calculation and improve the calculation efficiency, the load circuit breakers of the main distribution board corresponding to the power station with larger load are first sorted, and a search table is formed according to the load type and the size of the distribution power. The type is sorted first and then the current size. The types are sorted in order from low to high importance, and the current size is sorted from large to small. The load that can achieve non-stop power supply conversion between two power supplies is placed at the head of the table. After the sorting is completed, it is only necessary to calculate the objective function based on the search table from the head of the table until the load size relationship between the two power stations is converted. After the search is completed, the T value that minimizes the objective function and its corresponding load switch can be obtained.

[0067] S5, operate load power supply switching:

[0068] According to the previous step, the T loads obtained are cut off at the main switchboard corresponding to the power station with larger load, and these loads are automatically transferred to another power station for power supply.

[0069] Embodiment 2: This embodiment takes a ship power distribution system as an example. Figure 2 As shown, the ship is equipped with two power stations, front and rear, each of which includes two 400kW diesel generator sets and a main switchboard. The front and rear main switchboards are connected by a jumper wire, and the jumper wire is set to carry no less than the rated current of one generator set; the ship is also equipped with a set of distribution monitoring equipment, which can remotely monitor the working status and open and close control of all switches on the main switchboard; the front and rear main switchboards each have 28 load switches to supply power to the main loads of the entire ship, and each load is powered by two circuits from the front and rear main switchboards; a two-power automatic conversion device is set at the equipment end, which is used for short-term power outage conversion.

[0070] 1. Determine the load balance of dual power stations.

[0071] In the power distribution monitoring equipment, read the current total power P of the front and rear power stations for , P aft , and calculate the load difference between the two power stations ΔP=|P for -P aft |; When the power difference between the front and rear power stations reaches 200kW, that is, ΔP>200kW, the distribution reconstruction algorithm is started in the software.

[0072] 2. Load switching priority classification.

[0073] The loads on the motherboard are divided into three categories according to their importance.

[0074] Category I loads: including important equipment of the propulsion system and functional system, which are loads that affect the navigation or functional use of the ship, with high power supply continuity and power outages are not allowed in principle;

[0075] Class II loads: including general equipment of the propulsion system and general equipment of the functional system, which should be powered off as much as possible;

[0076] Three types of loads: such as air-conditioning chillers, air-conditioning cabinets, kitchen equipment, etc., their power supply can be cut off when necessary to ensure that the power system is not overloaded.

[0077] According to the above classification, when reconstructing the distribution system, priority is given to adjusting Class III loads, followed by Class II loads, and finally Class I loads. For some extremely important equipment in Class I loads, considering the continuity of power supply, no adjustment is made unless there is a fault.

[0078] 3. Set the distribution network reconstruction objective function and parameters.

[0079] The distribution network reconstruction objective function is as follows:

[0080]

[0081] Each power value is the real-time data of the power grid collected and calculated by the power distribution monitoring. The program sets the load switch action cost P iavr The value of K is 10kW, the value of λ for Class III load is 1 / 3, the value of λ for Class II load is 1 / 2, and the value of λ for Class I load is 1; the value of λ for some extremely important loads is 100, which is limited to not act during power distribution reconstruction. i Take 1.

[0082] 4. Calculate the minimum number of switch actions and the corresponding load switch

[0083] The power distribution monitoring equipment collects the current data of all load switches on the front and rear main distribution boards, and sorts them according to the load type and current size, first the type and then the current size. The types are in the order of first three types, then two types, and then one type of load, and the current size is sorted from large to small to form a search table. After the sorting is completed, the software automatically calculates the objective function from the table head based on the search table until the load size relationship between the two power stations is converted. After the search is completed, the T value that minimizes the objective function and its corresponding load switch can be obtained, and a prompt will be given on the display device of the power distribution monitoring equipment.

[0084] 5. Operate load power supply switching

[0085] The operator cuts off T loads on the corresponding main distribution board according to the display results of the distribution monitoring equipment. After the cut-off, the two power conversion devices automatically operate to switch the load power supply to another main distribution board, thus completing the load power supply switching and realizing the load balancing control of the dual power station distribution.

[0086] Furthermore, all parts involved in this application that are not described in detail are the same as the prior art or are implemented using the prior art.

[0087] In summary:

[0088] 1. The present invention can accurately control the load power supply switching according to the real-time operation of the ship power grid and realize the load balancing control of the dual power stations through the steps of load balancing judgment of the dual power stations, load switching priority classification, setting the distribution network reconstruction objective function and parameters, calculating the minimum number of switch actions and the corresponding load switch, and operating the load power supply switching;

[0089] 2. The present invention uses software to solve functions and output results. In the process of load balancing control of dual power station distribution, it does not rely on the personal judgment and decision of the operator. By presetting the objective function and parameters, the switch required for switching control can be accurately calculated;

[0090] 3. The present invention takes into account the differences between different loads. In the process of controlling the switching switch, it can effectively reduce the impact range of power outages, minimize the possibility of short-term power outages of important loads, and improve the performance of the ship's power distribution system.

[0091] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual-station power distribution load balancing control method, characterized in that: The steps include: S1, dual power station load balance judgment: calculate the power difference value of the two power stations, when the difference value is not greater than the set value, judge that the two power stations are in a load balance state, when the difference value is greater than the set value, judge that the two power stations are in a load non-balanced state, and execute subsequent steps; S2, load switching priority classification: according to whether there is a power outage during the load power supply switching process, the importance of the load, and the impact of a short-term power outage on the load, the power supply switching priority of each load on the ship is set; S3, setting the distribution network reconstruction objective function and parameters; S4, calculating the minimum number of switch actions and the corresponding load switch: calculating the load circuit breaker operation number value corresponding to the minimum value of the distribution network reconstruction objective function, and recording the corresponding load circuit breaker; S5, operate the load power supply switching: after the operator cuts off the corresponding load circuit breaker on the main distribution board corresponding to the power station with a larger load, the two power conversion devices are automatically operated to switch the load power supply to the main distribution board corresponding to the power station with a smaller load, thereby completing the load power supply switching.

2. According to claim 1, a dual-station power distribution load balancing control method is characterized in that In step S1, the current total power P of the two power stations is read through the power distribution monitoring device. for , P aft , and calculate the power difference between the two power stations ΔP=|P for -P aft |; When the power difference value ΔP is greater than the set value, the subsequent steps are continued.

3. A dual-station power distribution load balancing control method according to claim 1, characterized in that In step S2, setting the power supply switching priority of each load on the ship specifically includes: Classify the equipment in the ship's propulsion system and mission function system that is not allowed to be powered off during navigation as a priority load; The equipment in the ship's propulsion system and mission function system that can lose power for a short time during navigation is divided into the second category of priority loads; Divide the ship's other non-propulsion systems and mission function system-related equipment into three priority loads; The load with a higher power supply switching priority has a higher priority in switching when the power supply of the dual power station loads is switched.

4. A dual-station power distribution load balancing control method according to claim 1, characterized in that In step S3, the parameters related to the distribution network reconstruction objective function include: the power difference between the two power stations, the number of load circuit breaker operations on the main distribution board, the cost weight of the load circuit breaker operation on the main distribution board, the load weight of the corresponding power supply equipment, the power of the corresponding power supply equipment and the power outage mark.

5. A dual-station power distribution load balancing control method according to claim 1, characterized in that In step S3, the distribution network reconstruction objective function is as follows: Where P for is the current total power of the former power station; P aft is the current total power of the rear power station; T is the number of operations of the load circuit breaker on the main distribution board; P iavr is the cost weight of the load circuit breaker action, which is generally 10kW, 20kW, etc. λ i The load weight of the power supply equipment corresponding to the load circuit breaker is selected according to the importance level; P i is the power of the corresponding power supply equipment; K i It is the power-off mark. If the load has two power supplies that are switched without power outage, K i =0, if it is a power failure conversion, then K i =1.

6. A dual-station power distribution load balancing control method according to claim 1, characterized in that In step S4, the calculation of the minimum number of switch actions specifically includes: 1) According to the power supply switching priority of each load and the size of the distribution power, the load circuit breakers on the main distribution board corresponding to the power station with a larger load are sorted to form a search table; 2) Based on the search table, calculate the objective function value corresponding to each load circuit breaker in sequence starting from the table head; 3) Determine the value of the number of operations T of the load circuit breaker on the main distribution board corresponding to the minimum value of the objective function.

7. A dual-station power distribution load balancing control method according to claim 6, characterized in that: The step of sorting the load circuit breakers on the main switchboard corresponding to the power station with a larger load specifically includes: First, the loads are sorted according to their power supply switching priorities, and arranged in a search table from front to back according to their power supply switching priorities; Then, for loads with the same power supply switching priority, they are sorted according to the size of the distribution power and arranged in the search table from large to small according to the distribution power; Finally, the device that can realize the non-stop switching of two power supplies is placed at the meter head.

8. A dual-station power distribution load balancing control method according to claim 7, characterized in that In step S5, the corresponding load circuit breaker is specifically: based on the search table, the corresponding load circuit breaker when the objective function value is minimum and all load circuit breakers that are arranged before the load circuit breaker in the search table are calculated.

9. A dual-station power distribution load balancing control method according to claim 8, characterized in that In step S5, when the corresponding load circuit breakers are all cut off, the two power conversion devices automatically operate to switch the corresponding loads to the main distribution board corresponding to the power station with smaller load, so as to realize the load balancing control of the dual power station distribution.

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