A power point access control method and system for power distribution terminals

Abstract

The present invention discloses a power point access control method and system for power distribution terminals, wherein the method comprises the following steps: obtaining a power supply side voltage signal and a system side voltage signal; calculating the power supply side voltage parameter and the system side voltage parameter respectively according to the obtained power supply side voltage signal and the system side voltage signal; determining a trigger signal according to a preset judgment rule: wherein, when the trigger signal is a power supply access instruction signal, the power point is connected to the power grid system; otherwise, according to the obtained power supply side voltage signal and the system side voltage signal and the preset prediction time, the predicted voltage parameters of the power supply side and the system side are calculated, and according to the preset prediction rule, the size of the predicted voltage parameter is judged to determine the trigger signal. The present invention can reduce the impact on the power grid system when the power point is connected, and at the same time avoid damage to the power electronic devices of the new energy power generation equipment.

Description

Technical Field

[0001] The invention relates to a power point access control method and system for a power distribution terminal, belonging to the technical field of automatic control of power distribution terminals in a power distribution network. Background Art

[0002] As the State Grid Corporation of China gradually advances in building a new power system, distributed new energy sources have begun to be widely connected. New energy power generation systems such as wind power and photovoltaic power generation have gradually replaced traditional thermal power systems. Distribution terminal equipment monitors the access points of distributed new energy sources. For wind power systems, the wind turbine drives the generator to generate electricity, which is converted into AC power that can be connected to the power grid through the converter unit. For photovoltaic power generation, the DC signal generated by the photovoltaic power generation panel is converted into AC signal through the inverter, and the photovoltaic power generation is connected to the grid through the grid connection point.

[0003] On the one hand, whether it is wind power or photovoltaic power generation system, due to the large random fluctuations and poor adjustability of the grid-connected power, a large impact current will be generated when connected to the grid, which will cause grid frequency deviation, voltage fluctuation and flicker, and further affect the steady-state voltage distribution and reactive power characteristics, increasing the uncontrollability of the grid.

[0004] On the other hand, the grid-connected inverter systems of new energy power generation are mostly composed of high-power power electronic devices such as thyristors and thyristors. Excessive grid shocks will cause the stability and reliability of power electronic devices to decrease, and further cause them to be damaged to a certain extent, ultimately causing damage to the grid-connected inverter device.

[0005] In this case, a dedicated grid-connected device is generally equipped to perform power point access operations under appropriate dynamic parameters of the power supply system and the grid system. For some application scenarios where multiple power points are accessed, multiple access devices need to be configured. Therefore, the equipment cost is increased to a certain extent. The current distribution network requires high equipment integration and strong fusion. Separate equipment not only increases the system construction cost, but is also not conducive to the integrated development of distribution equipment.

[0006] Therefore, the present application provides a power point access control method and system for a power distribution terminal. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a power point access control method and system for a distribution terminal, which can reduce the impact of power point access on the power grid system and avoid damage to power electronic devices of new energy power generation equipment.

[0008] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0009] In one aspect, the present invention provides a method for controlling power point access for a power distribution terminal, comprising the following steps:

[0010] Obtaining a power supply side voltage signal and a system side voltage signal;

[0011] Calculate the power supply side voltage parameter and the system side voltage parameter respectively according to the acquired power supply side voltage signal and the system side voltage signal;

[0012] According to the preset judgment rules, determine the trigger signal:

[0013] Wherein, when the trigger signal is a power supply access instruction signal, the power supply point is connected to the power grid system;

[0014] Otherwise, based on the acquired power supply side voltage signal and system side voltage signal and the preset prediction time, the predicted voltage parameters of the power supply side and the system side are calculated, and according to the preset prediction rules, the size of the predicted voltage parameters is judged to determine the trigger signal.

[0015] Further, the obtaining of the power supply side voltage signal and the system side voltage signal comprises:

[0016] The sampling frequency is 8000HZ;

[0017] The number of sampling points is: 800 power supply side voltage signals and 800 system side voltage signals.

[0018] Further, the calculating of the power supply side voltage parameter and the system side voltage parameter respectively according to the acquired power supply side voltage signal and the system side voltage signal comprises:

[0019] According to the acquired power supply side voltage signal and system side voltage signal, respectively calculate the power supply side signal phasor and the system side signal phasor;

[0020] According to the signal phasor on the power supply side and the signal phasor on the system side, the effective value of the voltage on the power supply side and the effective value of the voltage on the system side are calculated respectively;

[0021] According to the signal phasor on the power supply side and the signal phasor on the system side, the frequency value on the power supply side and the frequency value on the system side are calculated respectively;

[0022] The phase angle value on the power supply side and the phase angle value on the system side are calculated according to the signal phasor on the power supply side and the signal phasor on the system side respectively, and the phase angle difference between the power supply side and the system side is calculated according to the phase angle value on the power supply side and the phase angle value on the system side, the angular frequency is calculated according to the rate of change of the phase angle difference, and the frequency acceleration is calculated according to the rate of change of the angular frequency.

[0023] Further, the calculating the power supply side signal phasor and the system side signal phasor respectively according to the acquired power supply side voltage signal and the system side voltage signal comprises:

[0024]

[0025]

[0026] Among them, U` Rn is the real part of the signal phasor on the power supply side, U` In is the imaginary part of the signal phasor on the power supply side, u` k is the voltage signal on the power supply side at sampling point k, U Rn is the real part of the signal phasor on the system side, U In is the imaginary part of the signal phasor on the system side, u k is the voltage signal on the system side at k sampling points, and N is the total number of sampling points.

[0027] Further, the calculating of the power supply side frequency value and the system side frequency value respectively according to the power supply side signal phasor and the system side signal phasor comprises:

[0028] Traverse the real part sequence of the signal phasor on the power supply side and the real part sequence of the signal phasor on the system side, and calculate the frequency compensation sequence on the power supply side and the frequency compensation sequence on the system side respectively:

[0029] Among them, when and When , the frequency compensation value of the current sampling point on the power supply side and the frequency compensation sequence on the power supply side are calculated by the following formula:

[0030]

[0031] tmpBC` m =[tmBC`0,tmBC`1,tmBC`2,…tmBC` m ]

[0032] ID m =[id0,id1,id2,…id k ]

[0033] Among them, tmpBC` [m] is the frequency compensation value of the current sampling point on the power supply side, is the real part of the signal phasor on the power supply side before the current sampling point, is the real part of the signal phasor on the power supply side two points before the current sampling point, INT[] is the integer processing, T0 is the sampling period constant, tmpBC` m is the frequency compensation sequence on the power supply side, ID` m is the index sequence of the frequency compensation sequence on the power supply side;

[0034] when and When , the frequency compensation value of the current point on the system side is calculated by the following formula:

[0035]

[0036] tmpBCm =[tmBC0,tmBC1,tmBC2,…tmBC0]

[0037] ID m =[id0,id1,id2,…id k ]

[0038] Among them, tmpBC [m] is the frequency compensation value of the current sampling point on the system side, is the real part of the system-side signal phasor at the point before the current sampling point, is the real part of the system-side signal phasor two points before the current sampling point, tmpBC m is the frequency compensation sequence on the system side, ID m is the index sequence of the frequency compensation sequence on the system side;

[0039] According to the power supply side frequency compensation sequence and the system side frequency compensation sequence, the power supply side frequency value and the system side frequency value are calculated by the following formula:

[0040]

[0041]

[0042] Among them, f' is the frequency value on the power supply side, and f is the frequency value on the system side.

[0043] Further, the power supply side phase angle value and the system side phase angle value are calculated respectively according to the power supply side signal phasor and the system side signal phasor, and the phase angle difference between the power supply side and the system side is calculated according to the power supply side phase angle value and the system side phase angle value, the angular frequency is calculated according to the rate of change of the phase angle difference, and the frequency acceleration is calculated according to the rate of change of the angular frequency, including the following formula:

[0044]

[0045]

[0046] Δθ=[θ d0 ,θ d1 ,θ d2 ,…θ dk ]

[0047] ω=[ω0,ω1,ω2,…ω k ]

[0048] a=[a0,a1,a2,…a k ]

[0049] Among them, θ` is the phase angle value on the power supply side, θ is the phase angle value on the system side, Δθ is the phase angle difference, ω is the angular frequency sequence, and a is the frequency acceleration sequence.

[0050] Furthermore, the preset judgment rules include:

[0051] Determine the effective value of the voltage on the power supply side and the effective value of the voltage on the system side respectively:

[0052] When the effective value of the voltage on the power supply side is less than the preset voltage setting value, and / or the effective value of the voltage on the system side is less than the preset voltage setting value, the locking signal is triggered;

[0053] Otherwise, determine the magnitude of the power supply side frequency value and the system side frequency value respectively:

[0054] Wherein, when the frequency value on the power supply side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, and / or the frequency value on the system side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, the blocking signal is triggered;

[0055] Otherwise, determine the frequency difference between the power supply side and the system side:

[0056] Among them, when the frequency difference between the power supply side and the system side is greater than or equal to the frequency difference threshold I, the locking signal is triggered;

[0057] Otherwise, determine the magnitude of the frequency acceleration value:

[0058] Among them, when the frequency acceleration value is greater than the acceleration threshold, the locking signal is triggered;

[0059] Otherwise, determine the frequency difference and phase angle difference between the power supply side and the system side respectively:

[0060] Among them, when the frequency difference between the power supply side and the system side is less than the frequency difference threshold II, and the phase angle difference between the power supply side and the system side is less than the phase angle difference threshold, the power supply connection command signal is triggered.

[0061] Further, the calculating of the predicted voltage parameters of the power supply side and the system side according to the acquired power supply side voltage signal and the system side voltage signal and the preset predicted time includes:

[0062]

[0063]

[0064] Δθ pre =2·avg ω ·τ+avg a ·τ 2

[0065] Among them, avg w is the average angular frequency, avg a is the average frequency acceleration, Δθ pre is the predicted phase angle difference, and τ is the predicted time.

[0066] Furthermore, the preset prediction rules include:

[0067] Determine the size of the predicted phase angle difference and the phase angle difference:

[0068] When the predicted phase angle difference value is less than the phase angle difference value, and the absolute value of the difference between the predicted phase angle difference value and the phase angle difference value is less than 2°, the power supply connection command signal is triggered;

[0069] Otherwise a shutdown signal is triggered.

[0070] In another aspect, the present invention provides a power point access control system for a power distribution terminal, comprising:

[0071] An acquisition module, used for acquiring a power supply side voltage signal and a system side voltage signal;

[0072] A voltage parameter module, used to calculate power supply side voltage parameters and system side voltage parameters respectively according to the acquired power supply side voltage signal and system side voltage signal;

[0073] The rule module is used to determine the trigger signal according to the preset judgment rules:

[0074] Wherein, when the trigger signal is a power supply access instruction signal, the power supply point is connected to the power grid system;

[0075] Otherwise, the predicted voltage parameters of the power supply side and the system side are calculated according to the obtained power supply side voltage signal and the system side voltage signal and the preset prediction time, and the size of the predicted voltage parameters is determined according to the preset prediction rules to determine the trigger signal.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The present invention does not require external calculation software, but directly obtains the power supply side voltage signal and the system side voltage signal, calculates the power supply side voltage parameters and the system side voltage parameters, and avoids the influence of harmonics in existing calculation software equipment on the accuracy when calculating the power supply side frequency value and the system side frequency value; the present invention controls the access of distributed new energy power supply points through preset judgment rules and preset pre-judgment rules, which can reduce the impact of power supply point access on the power grid system and avoid damage to power electronic devices of new energy power generation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 Shown is a flow chart of an embodiment of a method for controlling power point access for a power distribution terminal of the present invention. DETAILED DESCRIPTION

[0079] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0080] Example 1

[0081] A power distribution terminal power point access control method, characterized in that it includes the following steps:

[0082] S1 obtains the voltage signal on the power supply side and the voltage signal on the system side;

[0083] In the application, the sampling frequency is 8000HZ;

[0084] The number of sampling points is: 800 power supply side voltage signals and 800 system side voltage signals.

[0085] S2 calculates the power supply side voltage parameter and the system side voltage parameter respectively according to the acquired power supply side voltage signal and the system side voltage signal;

[0086] S3 determines the trigger signal according to the preset judgment rules:

[0087] Wherein, when the trigger signal is a power supply access instruction signal, the power supply point is connected to the power grid system;

[0088] Otherwise, based on the acquired power supply side voltage signal and system side voltage signal and the preset prediction time, the predicted voltage parameters of the power supply side and the system side are calculated, and according to the preset prediction rules, the size of the predicted voltage parameters is judged to determine the trigger signal.

[0089] The present invention does not require external calculation software, but directly obtains the power supply side voltage signal and the system side voltage signal, calculates the power supply side voltage parameters and the system side voltage parameters, and avoids the influence of harmonics in existing calculation software equipment on the accuracy when calculating the power supply side frequency value and the system side frequency value; the present invention controls the access of distributed new energy power supply points through preset judgment rules and preset pre-judgment rules, which can reduce the impact of power supply point access on the power grid system and avoid damage to power electronic devices of new energy power generation equipment.

[0090] Example 2

[0091] Based on Example 1, this example introduces in detail a method for calculating power supply side voltage parameters and system side voltage parameters.

[0092] According to the obtained power supply side voltage signal and system side voltage signal, the power supply side voltage parameters and the system side voltage parameters are calculated respectively, including:

[0093] S21 calculates the power supply side signal phasor and the system side signal phasor respectively according to the acquired power supply side voltage signal and the system side voltage signal;

[0094] In the application, the acquired power supply side voltage signal and system side voltage signal are converted into data and drawn into a sampling curve. The power supply side signal phasor and system side signal phasor are calculated by the following formula:

[0095]

[0096]

[0097] Among them, U` Rn is the real part of the signal phasor on the power supply side, U` In is the imaginary part of the signal phasor on the power supply side, u` k is the voltage signal on the power supply side at sampling point k, U Rn is the real part of the signal phasor on the system side, U In is the imaginary part of the signal phasor on the system side, u k is the voltage signal on the system side at k sampling points, and N is the total number of sampling points.

[0098] In the application, the real part sequence of the power supply side signal phasor and the real part sequence of the system side signal phasor include the following formulas:

[0099] U` R =[U` r0, U` r1, U` r2,… U` rn, ]

[0100] U R =[U r0, U r1, U r2,… U rn, ]

[0101] Among them, U` R is the real part sequence of the signal phasor on the power supply side, U R Real part sequence of the system side signal phasor.

[0102] S22 calculates the effective value of the voltage on the power supply side and the effective value of the voltage on the system side according to the signal phasor on the power supply side and the signal phasor on the system side;

[0103] S23 calculates the power supply side frequency value and the system side frequency value respectively according to the power supply side signal phasor and the system side signal phasor;

[0104] In the application, the methods for calculating the power supply side frequency value and the system side frequency value include:

[0105] The real part sequence of the signal phasor on the power supply side and the real part sequence of the signal phasor on the system side are traversed to calculate the frequency compensation sequence on the power supply side and the frequency compensation sequence on the system side respectively, thus avoiding the influence of harmonics in the existing calculation software equipment on the accuracy of calculating the frequency value on the power supply side and the frequency value on the system side:

[0106] Among them, when and When , the frequency compensation value of the current sampling point on the power supply side and the frequency compensation sequence on the power supply side are calculated by the following formula:

[0107]

[0108] tmpBC` m =[tmBC`0,tmBC`1,tmBC`2,…tmBC` m ]

[0109] ID m =[id0,id1,id2,…id k ]

[0110] Among them, tmpBC` [m] is the frequency compensation value of the current sampling point on the power supply side, is the real part of the signal phasor on the power supply side before the current sampling point, is the real part of the signal phasor on the power supply side two points before the current sampling point, INT[] is the integer processing, T0 is the sampling period constant, tmpBC` m is the frequency compensation sequence on the power supply side, ID` m is the index sequence of the frequency compensation sequence on the power supply side;

[0111] In the application, the value range of k is [0,800].

[0112] when and When , the frequency compensation value of the current point on the system side is calculated by the following formula:

[0113]

[0114] tmpBC m =[tmBC0,tmBC1,tmBC2,…tmBC0]

[0115] ID m =[id0,id1,id2,…id k ]

[0116] Among them, tmpBC [m] is the frequency compensation value of the current sampling point on the system side, is the real part of the system-side signal phasor at the point before the current sampling point, is the real part of the system-side signal phasor two points before the current sampling point, tmpBC m is the frequency compensation sequence on the system side, ID m is the index sequence of the frequency compensation sequence on the system side;

[0117] Since the sampling frequency is fixed, the sampling interval is equidistant and is a fixed constant. Therefore, according to the power supply side frequency compensation sequence and the system side frequency compensation sequence, the power supply side frequency value and the system side frequency value are calculated by the following formula:

[0118]

[0119]

[0120] Among them, f' is the frequency value on the power supply side, and f is the frequency value on the system side

[0121] S24 calculates the power supply side phase angle value and the system side phase angle value according to the power supply side signal phasor and the system side signal phasor respectively, and calculates the phase angle difference between the power supply side and the system side according to the power supply side phase angle value and the system side phase angle value, calculates the angular frequency according to the rate of change of the phase angle difference, and calculates the frequency acceleration according to the rate of change of the angular frequency;

[0122] In the application, the phase angle value on the power supply side, the phase angle value on the system side, the phase angle difference, the angular frequency sequence, and the frequency acceleration sequence are calculated by the following formula:

[0123]

[0124]

[0125] Δθ=[θ d0 ,θ d1 ,θ d2 ,…θ dk ]

[0126] ω=[ω0,ω1,ω2,…ω k ]

[0127] a=[a0,a1,a2,…a k ]

[0128] Among them, θ` is the phase angle value on the power supply side, θ is the phase angle value on the system side, Δθ is the phase angle difference, ω is the angular frequency sequence, and a is the frequency acceleration sequence.

[0129] The phase angle difference is normalized in the range of [0°, 360°]: if the phase angle difference is less than -180°, the phase angle difference is updated by adding 360° to the original value of the phase angle difference; if the phase angle difference is greater than 180°, the phase angle difference is updated by subtracting 360° from the original value of the phase angle difference.

[0130] In the application, since the sampling frequency is fixed, the sampling intervals are equidistant, and the angular frequency and frequency acceleration are calculated by the following formula:

[0131] ω k =θ d[k] -θ d[k-1]

[0132] a k =ω [2] -ω [k]

[0133] a=[ω k -ω0,ω k-1 -ω1,ω k-2 -ω2,…ω2-ω k ]

[0134] Among them, ω k is the angular frequency of the k sampling point, a k is the frequency acceleration of the k sampling point.

[0135] Example 3

[0136] Based on Example 1 or 2, this example introduces the preset judgment rules in detail.

[0137] The preset judgment rules include:

[0138] S31 determines the effective value of the voltage on the power supply side and the effective value of the voltage on the system side respectively:

[0139] When the effective value of the voltage on the power supply side is less than the preset voltage setting value, and / or the effective value of the voltage on the system side is less than the preset voltage setting value, the locking signal is triggered;

[0140] In the application, the voltage setting value is preset according to the actual situation on site. The blocking signal includes the specific blocking reason and operation prompt, that is, the current external environment does not meet the power point access conditions, and the power supply side voltage signal and the system side voltage signal need to be re-acquired.

[0141] Otherwise go to step S32.

[0142] S32 determines the magnitude of the power supply side frequency value and the system side frequency value respectively:

[0143] Wherein, when the frequency value on the power supply side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, and / or the frequency value on the system side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, the blocking signal is triggered;

[0144] Otherwise go to step S33.

[0145] In the application, the frequency threshold I is 49HZ and the frequency threshold II is 51HZ.

[0146] S33 determines the magnitude of the frequency difference between the power supply side and the system side:

[0147] Among them, when the frequency difference between the power supply side and the system side is greater than or equal to the frequency difference threshold I, the locking signal is triggered;

[0148] Otherwise go to step S34.

[0149] In the application, the frequency difference threshold I is 0.5HZ.

[0150] S34 determines the magnitude of the frequency acceleration value:

[0151] Among them, when the frequency acceleration value is greater than the acceleration threshold, the locking signal is triggered;

[0152] Otherwise go to step S35.

[0153] In the application, the acceleration threshold is 3HZ / s.

[0154] S35 determines the frequency difference and phase angle difference between the power supply side and the system side respectively:

[0155] Among them, when the frequency difference between the power supply side and the system side is less than the frequency difference threshold II, and the phase angle difference between the power supply side and the system side is less than the phase angle difference threshold, the power access command signal is triggered, which can reduce the impact on the power grid system when the power point is connected, and at the same time avoid damage to the power electronic devices of the new energy power generation equipment.

[0156] In the application, the frequency difference threshold II is 0.02HZ; the phase angle difference threshold is 3°

[0157] Example 4

[0158] This embodiment introduces in detail the calculation method of the predicted voltage parameter.

[0159] Since the sampling frequency of this embodiment is fixed and periodic, there are sampling intervals and data window calculation intervals. Based on the phase angle difference calculated in real time as the basis for judgment, there will be conditions that will never meet the conditions for triggering the power access command signal in the judgment rule. At the same time, due to the instability of the distributed power supply in the distribution network system when it is connected, the frequency value on the power supply side and the frequency value on the system side are inconsistent. According to the actually calculated phase angle difference on the system side and the power supply side, the frequency acceleration and the preset prediction time, the predicted phase angle difference is calculated, including the following formula:

[0160]

[0161]

[0162] Δθpre =2·avg ω ·τ+avg a ·τ 2

[0163] Among them, avg w is the average angular frequency, avg a is the average frequency acceleration, Δθ pre is the predicted phase angle difference, and τ is the predicted time.

[0164] Example 5

[0165] Based on Example 4, this example introduces the preset prediction rules in detail.

[0166] The preset prediction rules include:

[0167] Determine the size of the predicted phase angle difference and the phase angle difference:

[0168] Among them, when the predicted phase angle difference is less than the phase angle difference, and the absolute value of the difference between the predicted phase angle difference and the phase angle difference is less than 2°, the power access command signal is triggered, which can reduce the impact on the power grid system when the power point is connected, and avoid damage to the power electronic devices of the new energy power generation equipment;

[0169] Otherwise a shutdown signal is triggered.

[0170] Example 6

[0171] This embodiment introduces in detail a power point access control system for a power distribution terminal, including:

[0172] An acquisition module, used for acquiring a power supply side voltage signal and a system side voltage signal;

[0173] A voltage parameter module, used to calculate power supply side voltage parameters and system side voltage parameters respectively according to the acquired power supply side voltage signal and system side voltage signal;

[0174] The rule module is used to determine the trigger signal according to the preset judgment rules:

[0175] Wherein, when the trigger signal is a power supply access instruction signal, the power supply point is connected to the power grid system;

[0176] Otherwise, based on the acquired power supply side voltage signal and system side voltage signal and the preset prediction time, the predicted voltage parameters of the power supply side and the system side are calculated, and according to the preset prediction rules, the size of the predicted voltage parameters is judged to determine the trigger signal.

[0177] The specific functional implementation of each of the above functional modules refers to the relevant contents in the methods of Examples 1-5.

[0178] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0179] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0180] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0181] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0182] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A power point access control method for a power distribution terminal, characterized in that: The following steps are involved: Obtaining a power supply side voltage signal and a system side voltage signal; Calculate the power supply side voltage parameter and the system side voltage parameter respectively according to the acquired power supply side voltage signal and the system side voltage signal; According to the preset judgment rules, determine the trigger signal: Wherein, when the trigger signal is a power supply access instruction signal, the power supply point is connected to the power grid system; Otherwise, the predicted voltage parameters of the power supply side and the system side are calculated according to the acquired power supply side voltage signal and the system side voltage signal and the preset prediction time, and the magnitude of the predicted voltage parameters is determined according to the preset prediction rules to determine the trigger signal; The obtaining of the power supply side voltage signal and the system side voltage signal comprises: The sampling frequency is 8000HZ; The number of sampling points is: 800 power supply side voltage signals and 800 system side voltage signals; The preset judgment rules include: Determine the effective value of the voltage on the power supply side and the effective value of the voltage on the system side respectively: When the effective value of the voltage on the power supply side is less than the preset voltage setting value, and / or the effective value of the voltage on the system side is less than the preset voltage setting value, the locking signal is triggered; Otherwise, determine the magnitude of the power supply side frequency value and the system side frequency value respectively: Wherein, when the frequency value on the power supply side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, and / or the frequency value on the system side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, the blocking signal is triggered; Otherwise, determine the frequency difference between the power supply side and the system side: Among them, when the frequency difference between the power supply side and the system side is greater than or equal to the frequency difference threshold I, the locking signal is triggered; Otherwise, determine the magnitude of the frequency acceleration value: Among them, when the frequency acceleration value is greater than the acceleration threshold, the locking signal is triggered; Otherwise, determine the frequency difference and phase angle difference between the power supply side and the system side respectively: When the frequency difference between the power supply side and the system side is less than the frequency difference threshold II, and the phase angle difference between the power supply side and the system side is less than the phase angle difference threshold, the power supply connection command signal is triggered; The preset prediction rules include: Determine the size of the predicted phase angle difference and the phase angle difference: When the predicted phase angle difference value is less than the phase angle difference value, and the absolute value of the difference between the predicted phase angle difference value and the phase angle difference value is less than 2°, the power supply connection command signal is triggered; Otherwise a shutdown signal is triggered.

2. The power point access control method for power distribution terminals according to claim 1, characterized in that: The step of respectively calculating the power supply side voltage parameter and the system side voltage parameter according to the acquired power supply side voltage signal and the system side voltage signal comprises: According to the acquired power supply side voltage signal and system side voltage signal, respectively calculate the power supply side signal phasor and the system side signal phasor; According to the signal phasor on the power supply side and the signal phasor on the system side, the effective value of the voltage on the power supply side and the effective value of the voltage on the system side are calculated respectively; According to the signal phasor on the power supply side and the signal phasor on the system side, the frequency value on the power supply side and the frequency value on the system side are calculated respectively; The phase angle value on the power supply side and the phase angle value on the system side are calculated according to the signal phasor on the power supply side and the signal phasor on the system side respectively, and the phase angle difference between the power supply side and the system side is calculated according to the phase angle value on the power supply side and the phase angle value on the system side, the angular frequency is calculated according to the rate of change of the phase angle difference, and the frequency acceleration is calculated according to the rate of change of the angular frequency.

3. The power distribution terminal power point access control method according to claim 2, characterized in that: The method of calculating the power supply side signal phasor and the system side signal phasor respectively according to the acquired power supply side voltage signal and the system side voltage signal comprises: Among them, U Rn is the real part of the signal phasor on the power supply side, U' In is the imaginary part of the signal phasor on the power supply side, u' k is the voltage signal on the power supply side at sampling point k, U Rn is the real part of the signal phasor on the system side, U In is the imaginary part of the signal phasor on the system side, u k is the voltage signal on the system side at k sampling points, and N is the total number of sampling points.

4. The power point access control method for power distribution terminals according to claim 2, characterized in that: The method of calculating the power supply side frequency value and the system side frequency value respectively according to the power supply side signal phasor and the system side signal phasor comprises: Traverse the real part sequence of the signal phasor on the power supply side and the real part sequence of the signal phasor on the system side, and calculate the frequency compensation sequence on the power supply side and the frequency compensation sequence on the system side respectively: Among them, when and When , the frequency compensation value of the current sampling point on the power supply side and the frequency compensation sequence on the power supply side are calculated by the following formula: tmpBC` m =[tmBC`0,tmBC`1,tmBC`2,...tmBC` m ] ID` m =[id0,id1,id2,...id k ] Among them, tmpBC' [m] is the frequency compensation value of the current sampling point on the power supply side, is the real part of the signal phasor on the power supply side before the current sampling point, is the real part of the signal phasor on the power supply side two points before the current sampling point, INT[] is the integer processing, T0 is the sampling period constant, tmpBC' m is the frequency compensation sequence on the power supply side, ID' m is the index sequence of the frequency compensation sequence on the power supply side; when and When , the frequency compensation value of the current point on the system side is calculated by the following formula: tmpBC m =[tmBC0,tmBC1,tmBC2,...tmBC0] ID m =[id0,id1,id2,...id k ] Among them, tmpBC [m] is the frequency compensation value of the current sampling point on the system side, is the real part of the system-side signal phasor at the point before the current sampling point, is the real part of the system-side signal phasor two points before the current sampling point, tmpBC m is the frequency compensation sequence on the system side, ID m is the index sequence of the frequency compensation sequence on the system side; According to the power supply side frequency compensation sequence and the system side frequency compensation sequence, the power supply side frequency value and the system side frequency value are calculated by the following formula: Among them, f' is the frequency value on the power supply side, and f is the frequency value on the system side.

5. The power point access control method for power distribution terminals according to claim 2, characterized in that: The method of calculating the phase angle value of the power supply side and the phase angle value of the system side respectively according to the power supply side signal phasor and the system side signal phasor, and calculating the phase angle difference between the power supply side and the system side according to the power supply side phase angle value and the system side phase angle value, calculating the angular frequency according to the rate of change of the phase angle difference, and calculating the frequency acceleration according to the rate of change of the angular frequency, includes the following formula: Δθ=[θ d0 ,the d1 ,the d2 ,...θ dk ] ω=[ω0,ω1,ω2,...ω k ] <h2 style=";text-align:left;direction:ltr">a=[a0,a1,a2,...a<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> ] Among them, θ' is the phase angle value on the power supply side, θ is the phase angle value on the system side, Δθ is the phase angle difference, ω is the angular frequency sequence, and a is the frequency acceleration sequence.

6. The power distribution terminal power point access control method according to claim 1, characterized in that: The step of calculating the predicted voltage parameters of the power supply side and the system side according to the acquired power supply side voltage signal and the system side voltage signal and the preset predicted time includes: Dth pre =2·avg ω ·t+avg a ·t 2 Among them, avg w is the average angular frequency, avg a is the average frequency acceleration, Δθ pre is the predicted phase angle difference, and τ is the predicted time.

7. A power point access control system for a power distribution terminal, characterized in that: include: An acquisition module, used for acquiring a power supply side voltage signal and a system side voltage signal; A voltage parameter module, used to calculate power supply side voltage parameters and system side voltage parameters respectively according to the acquired power supply side voltage signal and system side voltage signal; The rule module is used to determine the trigger signal according to the preset judgment rules: Wherein, when the trigger signal is a power supply access instruction signal, the power supply point is connected to the power grid system; Otherwise, the predicted voltage parameters of the power supply side and the system side are calculated according to the acquired power supply side voltage signal and the system side voltage signal and the preset prediction time, and the magnitude of the predicted voltage parameters is determined according to the preset prediction rules to determine the trigger signal; The obtaining of the power supply side voltage signal and the system side voltage signal comprises: The sampling frequency is 8000HZ; The number of sampling points is: 800 power supply side voltage signals and 800 system side voltage signals; The preset judgment rules include: Determine the effective value of the voltage on the power supply side and the effective value of the voltage on the system side respectively: When the effective value of the voltage on the power supply side is less than the preset voltage setting value, and / or the effective value of the voltage on the system side is less than the preset voltage setting value, the locking signal is triggered; Otherwise, determine the magnitude of the power supply side frequency value and the system side frequency value respectively: Wherein, when the frequency value on the power supply side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, and / or the frequency value on the system side is less than or equal to the frequency threshold I or greater than or equal to the frequency threshold II, the blocking signal is triggered; Otherwise, determine the frequency difference between the power supply side and the system side: Among them, when the frequency difference between the power supply side and the system side is greater than or equal to the frequency difference threshold I, the locking signal is triggered; Otherwise, determine the magnitude of the frequency acceleration value: Among them, when the frequency acceleration value is greater than the acceleration threshold, the locking signal is triggered; Otherwise, determine the frequency difference and phase angle difference between the power supply side and the system side respectively: When the frequency difference between the power supply side and the system side is less than the frequency difference threshold II, and the phase angle difference between the power supply side and the system side is less than the phase angle difference threshold, the power supply connection command signal is triggered; The preset prediction rules include: Determine the size of the predicted phase angle difference and the phase angle difference: When the predicted phase angle difference value is less than the phase angle difference value, and the absolute value of the difference between the predicted phase angle difference value and the phase angle difference value is less than 2°, the power supply connection command signal is triggered; Otherwise a shutdown signal is triggered.

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