A method for distributing power generated by parallel diesel generators

Abstract

The present application relates to power generation control and automation field, specifically to a kind of heteromorphous diesel generator parallel operation power distribution method, including real-time acquisition of the operating state parameters and unit inherent parameters of each generator set in parallel operation according to preset sampling period;In each control cycle, based on the operating state parameters and the inherent parameters, the comprehensive performance evaluation index of each generator set is determined;Wherein the value of the comprehensive performance evaluation index is updated with the state change of each generator set;According to the comprehensive performance evaluation index of each generator set, the target active power value is allocated for the corresponding generator set;Based on the target active power value, control instruction is generated and issued to the corresponding generator set to adjust its actual power output.

Description

Technical Field

[0001] This invention relates to the field of power generation control and automation technology, specifically a method for parallel power generation and distribution of non-standard diesel generators. Background Technology

[0002] With increasing societal demands for continuous power supply, the need for temporary and emergency power supply is growing in various scenarios, including power grid maintenance, natural disaster emergencies, large-scale event support, and construction in remote areas. In these applications, multiple diesel generator sets are often deployed on-site to provide necessary power support. However, the capacity of a single generator set is typically limited and insufficient to meet the demands of large loads or the entire power supply area. Therefore, operating multiple generator sets in parallel has become a key technical means to expand the total system capacity and improve power supply reliability and redundancy.

[0003] The basic goal of multi-unit parallel operation is to enable all units to share the total load. For identical units with the same model, capacity, and performance parameters, power sharing can usually be achieved using strategies such as frequency-power droop control or simple capacity ratio allocation. However, in practical engineering applications, due to equipment procurement cycles, site conditions, or upgrades, there are often situations where it is necessary to operate diesel generator sets of different brands, rated capacities, and dynamic performance (such as speed regulation response speed and excitation characteristics) in parallel. These units are collectively referred to as "dissimilar" generator sets.

[0004] Parallel operation of dissimilar generator sets faces numerous technical challenges. First, the inherent differences in the governor and excitation control system characteristics of each unit result in varying response speeds and steady-state regulation accuracy to load changes. If a simple equal or fixed-ratio allocation strategy is adopted, slower-responding units may fail to keep up with load changes, while faster-responding units may bear excessive transient loads, easily leading to overload or frequent adjustments, thus affecting system frequency stability. Second, the operating economy (fuel consumption rate) of different units varies significantly. Ignoring efficiency factors and having high-fuel-consuming units bear the majority of the load for an extended period will result in extremely high operating costs. Furthermore, the health status of the units themselves (such as cooling water temperature, oil pressure, and historical maintenance records) should also be an important basis for allocation decisions to prevent the spread of fault risks. Summary of the Invention

[0005] The purpose of this invention is to provide a method for parallel power generation and distribution of non-standard diesel generators, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for parallel power generation and distribution of non-standard diesel generators, comprising: According to the preset sampling period, the operating status parameters and inherent parameters of each generator set operating in parallel are collected in real time. Within each control cycle, a comprehensive performance evaluation index for each generator set is determined based on the operating status parameters and the inherent parameters; wherein the value of the comprehensive performance evaluation index is updated as the status of each generator set changes. Based on the comprehensive performance evaluation indicators of each generator set, target active power values ​​are allocated to the corresponding generator sets. Based on the target active power value, control commands are generated and sent to the corresponding generator set to adjust its actual power output.

[0007] Optionally, determining the comprehensive performance evaluation index of each generator set based on the operating status parameters and the inherent parameters includes: Based on the operating status parameters and the inherent parameters, at least two performance evaluation factors are determined; wherein, the performance evaluation dimensions corresponding to each performance evaluation factor are different. Based on the at least two performance evaluation factors, the comprehensive performance evaluation index of each generator set is determined.

[0008] Optionally, the performance factors include a first factor characterizing the steady-state load-carrying capacity of the generator set, a second factor characterizing the dynamic response speed of the generator set, a third factor characterizing the operating health status of the generator set, a fourth factor characterizing the frequency support capacity of the generator set system, and a fifth factor characterizing the operating economy of the generator set.

[0009] Optionally, the first factor is determined based on the rated capacity of the generator set; the second factor is determined based on the preset power change rate of the generator set; the third factor is determined based on the real-time alarm or fault status of the generator set; the fourth factor is determined based on the equivalent inertia constant of the generator set; and the fifth factor is determined based on the fuel consumption rate of the generator set.

[0010] Optionally, weight coefficients are configured for each performance evaluation factor, and each performance evaluation factor and its corresponding weight coefficient are weighted and summed to obtain the preliminary weight value corresponding to each generator set.

[0011] Optionally, the third factor is a binary switch factor, which takes the value of zero when the generator set is in an abnormal state.

[0012] Optionally, the step of allocating target active power values ​​to the corresponding generator sets based on the comprehensive performance evaluation index includes: The initial weight values ​​of each generator set are normalized to obtain the comprehensive performance evaluation index of each unit. The comprehensive performance evaluation index of each generator set is used as the active power allocation ratio of each generator set. The target active power value of each generator set is determined based on the total active load demand and the active power allocation ratio of each generator set.

[0013] Optionally, the method further includes: Monitor the rate of change in total active power load demand; When the rate of change exceeds a preset threshold, it is determined to be a load mutation condition, and in the next control cycle, the weight coefficients configured for the second factor and / or the fourth factor when the comprehensive performance evaluation index is obtained are temporarily increased.

[0014] Optionally, the operating status parameters include at least a variety of the following: output voltage, current, active power, reactive power, frequency, temperature, and fault indicators at each generator terminal; the inherent parameters of the unit include at least a variety of the following: rated active power, maximum allowable output, power rise / fall rate, equivalent inertia constant, and fuel efficiency parameters.

[0015] Optionally, the method further includes: Based on the rated reactive power capacity and current operating status of each generator set, a target reactive power value is allocated to each generator set. Compared with existing technologies, the beneficial effects of this invention are as follows: This invention achieves a precise profile of the real-time capabilities and contributions of each generator set by comprehensively measuring various performance evaluation factors. The parallel system can be compatible with different types of generator sets with different models, capacities, and performance. Active load can be dynamically and rationally distributed to each generator set most suitable for the current operating conditions. For the first time, inertial contribution, transient response capability, and fuel efficiency are systematically incorporated into the allocation decision. During steady-state operation, generator sets with high fuel efficiency are given priority to carry more load, reducing total fuel consumption. During sudden load changes, generator sets with fast response and high inertia are automatically assigned to bear more impact components, effectively suppressing frequency fluctuations and improving system transient stability. It can ensure system frequency stability by utilizing high-inertia, fast-response generator sets during transient processes, and prioritize the scheduling of high-efficiency generator sets during steady-state operation, reducing overall fuel consumption. It can also effectively prevent overload operation of faulty generator sets, avoid the escalation of faults, and provide maintenance personnel with a handling window. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for parallel power generation and distribution of non-standard diesel generators according to the present invention; Figure 2 This is a schematic diagram of a parallel system according to an embodiment of the present invention. Detailed Implementation

[0017] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example: Figures 1-2 As shown, this invention provides a method for parallel power generation distribution of dissimilar diesel generator sets, applicable to parallel systems composed of multiple diesel generator sets of different capacities, models, and performance. The method is executed by a combiner controller (i.e., a parallel controller), which adopts a dual-core architecture of a DSP (Digital Signal Processor) and an FPGA (Field-Programmable Gate Array). The FPGA is responsible for high-speed, synchronous sampling and filtering preprocessing of voltage and current signals acquired by multiple ADCs (Analog-to-Digital Converters). The DSP is responsible for running the core control algorithm, including synchronization judgment, multi-factor calculation, and power distribution. The controller is equipped with CAN2.0B and RS-485 communication interfaces to adapt to the communication protocols of different brands of generator set controllers. like Figure 1 An exemplary system architecture is shown, comprising multiple diesel generator sets (G1, G2, …, GN) connected to a combiner box busbar via their respective outgoing circuit breakers. The busbar is connected to the power grid or load via a main circuit breaker. The aforementioned allocation method is executed cyclically at a fixed period (e.g., 100ms) after grid connection. In the allocation method, as shown... Figure 2 As shown, it includes the following steps: Step S101: Collect the operating status parameters and inherent parameters of each generator set operating in parallel in real time according to the preset sampling period; Step S102: Within each control cycle, based on the operating status parameters and the inherent parameters, determine the comprehensive performance evaluation index of each generator set; wherein the value of the comprehensive performance evaluation index is updated as the status of each generator set changes; Step S103: Based on the comprehensive performance evaluation index of each generator set, allocate target active power values ​​to the corresponding generator sets; Step S104: Based on the target active power value, generate and send control commands to the corresponding generator set to adjust its actual power output.

[0019] In step S101, the operating status parameters and inherent parameters of each generator set operating in parallel are collected in real time according to a preset sampling period. Specifically, the following two types of parameters are collected in real time by the combiner controller: Operating status parameters (updated every sampling period): voltage, current, active power, reactive power, frequency, speed, winding temperature, oil pressure, oil temperature, and fault flags (such as overload, high temperature, communication interruption) for each generator terminal. Unit inherent parameters (obtained through pre-configuration or communication): rated active power, maximum allowable output, power rise / fall rate (unit: kW / min), equivalent inertia constant (unit: seconds), rated fuel consumption rate (unit: g / kWh). In step S102: within each control cycle, a comprehensive performance evaluation index for each generator set is determined based on the operating status parameters and the inherent parameters; wherein, the value of the comprehensive performance evaluation index is updated as the status of each generator set changes. If the sampling period is set to 100 ms, the control period is synchronized with it. In each control period, the comprehensive performance evaluation index of each generator set is calculated based on the parameters collected in step S101. The specific process is as follows: Based on the rated active power P of the i-th generator set ni Calculate the capacity factor C, which characterizes the steady-state load-carrying capacity, for the i-th generator unit. i :C i =P ni / (P n1 +P n2 +...+P nN ); where P n1 P n2 ... P nN These represent the rated active power of the first generator set, the second generator set, ..., the Nth generator set operating in parallel; Based on the power ramp-up rate (Ramprate) of the i-th generator set i Calculate the transient response capability factor R, which characterizes the dynamic response speed, for the i-th generator unit. i : Where Ramprate(max) represents the maximum power increase / decrease rate among N generator sets; based on whether the i-th generator set has alarms or fault status (reflected by current temperature, oil pressure, fault signs, etc.), the state factor S representing the operational health status of the i-th generator set is obtained. i Among them, the state factor S i It is a binary switching factor; When S i When H = 0, the unit does not participate in this power allocation. Based on the equivalent inertia constant H of the i-th generator unit... i Calculate the inertial contribution factor I, which characterizes the frequency support capability of the system, for the i-th generator unit. i :I i =H i / Hmax; where Hmax is the largest equivalent inertia constant among the N generator sets; based on the fuel consumption rate SFC of the i-th generator set. iCalculate the efficiency factor E, which characterizes the economic efficiency of operation. i E i =SFC min / SFC i Among them, SFC min Let SFC be the minimum fuel consumption rate of the i-th generator set at rated power; where SFC i =Q / (P i ×t), where Q is the fuel consumption during the sampling period t, P i Let W be the rated power of the i-th generator set; assign a weighting coefficient to each factor: W C W R W I W E ; Satisfy: W C +W R +W I +W E =1, all coefficients >0; Calculate the initial weight value of the i-th generator unit: W i =S i ×(W C C i +W R R i +W I I i +W E E i ); The initial weights of the currently online and normal generator sets are normalized to obtain the comprehensive performance evaluation index of the i-th generator set: F i =W i / (W1+W2+...+W N ); where W1, W2, ..., W N These represent the initial weight values ​​for the 1st, 2nd, ..., Nth generator sets, respectively. The controller obtains the current total active load demand Ptotal (which can be calculated from the total bus current and voltage, or given by the host system).

[0020] The target active power value of the i-th generator set is: Ptarget i =F i ×Ptotal; If the i-th generator set Ptarget i If the power is greater than Pmax, then the limit is Pmax, and the remaining power is determined by F. i The proportion is redistributed to other generating units; where Pmax is the maximum target active power value of a single generating unit; The controller will Ptarget i The CAN2.0B communication protocol is used to send commands to the local controllers (such as speed governors and excitation controllers) of each generator set; each generator set adjusts the throttle opening (active power) and excitation current (reactive power) according to the received commands to achieve power tracking. For example, set the weighting coefficient: W C =0.3,W R =0.2,W I =0.2,W E =0.3; After calculating each factor and weighting and normalizing, we get F1=0.45, F2=0.30, F3=0.25; If the total active power load demand is 800 kW, then the allocation result is: P1=360kW, P2=240kW, P3=200kW; The system issues instructions according to this allocation and updates the allocation based on real-time data in the next cycle.

[0021] In this application, if the rate of change of Ptotal exceeds a threshold, such as 10%, in adjacent cycles, the system determines it to be a load change condition and temporarily increases W in the next control cycle. R and W I The weights, for example, are all increased to 0.3, so that units with fast response and high inertia are given priority to bear the fluctuations; After completing the active power allocation, this application can allocate reactive power in a similar manner, collect the rated reactive power capacity Qni and the current reactive power output Qi of each generator set, construct a reactive power allocation factor (which can be based on capacity, voltage regulation capability, etc.), calculate the target reactive power value Qtargeti, and achieve it through excitation system adjustment.

[0022] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for parallel power generation and distribution of non-standard diesel generators, characterized in that, The method includes: According to the preset sampling period, the operating status parameters and inherent parameters of each generator set operating in parallel are collected in real time. Within each control cycle, a comprehensive performance evaluation index for each generator set is determined based on the operating status parameters and the inherent parameters; wherein the value of the comprehensive performance evaluation index is updated as the status of each generator set changes. Based on the comprehensive performance evaluation indicators of each generator set, target active power values ​​are allocated to the corresponding generator sets. Based on the target active power value, control commands are generated and sent to the corresponding generator set to adjust its actual power output.

2. The method according to claim 1, characterized in that, The determination of the comprehensive performance evaluation index for each generator set based on the operating status parameters and the inherent parameters includes: Based on the operating status parameters and the inherent parameters, at least two performance evaluation factors are determined; wherein, the performance evaluation dimensions corresponding to each performance evaluation factor are different from each other. Based on the at least two performance evaluation factors, the comprehensive performance evaluation index of each generator set is determined.

3. The method according to claim 2, characterized in that, The performance factors include a first factor characterizing the steady-state load-carrying capacity of the generator set, a second factor characterizing the dynamic response speed of the generator set, a third factor characterizing the operating health status of the generator set, a fourth factor characterizing the frequency support capability of the generator set system, and a fifth factor characterizing the operating economy of the generator set.

4. The method according to claim 3, characterized in that, The first factor is determined based on the rated capacity of the generator set; the second factor is determined based on the preset power change rate of the generator set; the third factor is determined based on the real-time alarm or fault status of the generator set; the fourth factor is determined based on the equivalent inertia constant of the generator set; and the fifth factor is determined based on the fuel consumption rate of the generator set.

5. The method according to claim 2, characterized in that, Assign weight coefficients to each performance evaluation factor, and sum the weighted values ​​of each performance evaluation factor and its corresponding weight coefficient to obtain the preliminary weight values ​​for each generator set.

6. The method according to claim 4, characterized in that, The third factor is a binary switching factor, which takes the value of zero when the generator set is in an abnormal state.

7. The method according to claim 5 or 6, characterized in that, The process of allocating target active power values ​​to the corresponding generator sets based on the comprehensive performance evaluation indicators includes: The initial weight values ​​of each generator set are normalized to obtain the comprehensive performance evaluation index of each unit. The comprehensive performance evaluation index of each generator set is used as the active power allocation ratio of each generator set. The target active power value of each generator set is determined based on the total active load demand and the active power allocation ratio of each generator set.

8. The method according to claim 4, characterized in that, The method further includes: Monitor the rate of change in total active power load demand; When the rate of change exceeds a preset threshold, it is determined to be a load mutation condition, and in the next control cycle, the weight coefficients configured for the second factor and / or the fourth factor when the comprehensive performance evaluation index is obtained are temporarily increased.

9. The method according to claim 1, characterized in that, The operating status parameters include at least several of the following: output voltage, current, active power, reactive power, frequency, temperature, and fault indicators at each generator terminal; the inherent parameters of the unit include at least several of the following: rated active power, maximum allowable output, power rise / fall rate, equivalent inertia constant, and fuel efficiency parameters.

10. The method according to claim 1, characterized in that, The method further includes: Based on the rated reactive power capacity and current operating status of each generator set, a target reactive power value is assigned to each generator set.

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