Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/08—Locating faults in cables, transmission lines, or networks
  • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
  • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
  • H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
  • Y02E40/70—Smart grids as climate change mitigation technology in the energy generation sector
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
  • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
  • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
  • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
  • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
  • Y04S10/22—Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
  • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
  • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
  • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
  • Y04S10/52—Outage or fault management, e.g. fault detection or location

Definitions

• the present invention relates to power system dispatching automation and safe operation of a power grid, and more particularly to determining a location of a forced power oscillation source of a regional interconnected power grid.
• the power system Under the disturbance, the power system will have relative sway between the rotors of the motor and cause continuous oscillation in the absence of damping.
• the oscillation frequency ranges from 0.1 to 2.5 Hz, so it is called low frequency oscillation.
• the low-frequency oscillation problem belongs to the category of small disturbance stability. With the expansion of interconnected power systems, the operation of long-distance heavy-duty transmission systems, the application of fast automatic excitation regulators and fast excitation systems, low-frequency oscillations have occurred in many power systems at home and abroad. Problem, low frequency oscillation is one of the important factors affecting the safe and stable operation of the power system.
• Forced power oscillation is a form of low frequency oscillation, that is, when the frequency of the system being subjected to continuous periodic power disturbance is close to the natural frequency of system power oscillation, a large power oscillation is caused.
• the actual case analysis of the power grid demonstrates that the most effective treatment for forced power oscillation is to quickly find and remove the disturbance source, but no specific method for finding the disturbance source is proposed.
• the wide-area measurement system consists of a Global Positioning System (GPS)-based synchronized phasor measurement unit (PMU) and its communication system, capable of synchronous, high-speed acquisition of active power of units and operating equipment in a wide-area power system, Power, voltage, current, phase angle, and important switching signals are tools that can monitor and analyze dynamic processes in power systems.
• GPS Global Positioning System
• PMU synchronized phasor measurement unit
• the wide-area measurement system provides new technical means for monitoring the frequency oscillation of the power grid, analyzing the oscillation event, and preventing and suppressing the oscillation.
• the sum of the potential energies of the nodes is equal to the potential energy of the outflow node, and the potential energy of the generator can be represented by the branch potential energy connected to it.
• the branch between the i-node and the j-node in the system is L, and its i-terminal potential energy function is:
• t is the disturbance time.
• this method needs to find the branch potential energy function by integral.
• the calculation process is more complicated and is not conducive to real-time calculation.
• the position of the disturbance source is mainly determined by the non-periodic component, and the periodic component of the potential energy function is The selection of the initial value of the integral will have a certain interference to the accuracy of the judgment.
• each state quantity changes periodically with a disturbance frequency, for a node in the power grid; and a branch between the nodes,
• the oscillation frequency ⁇ 3 ⁇ 4 ⁇ ⁇ ⁇ ( ⁇ 3 ⁇ 4+ ⁇ ), where ⁇ and ⁇ 3 ⁇ 4 are the branch power and the amplitude of the i-terminal frequency, respectively, 3 ⁇ 4, the branch power and the initial phase change of the end frequency, which is the disturbance frequency;
• the potential energy function is:
• the potential energy function is composed of a sinusoid with a magnitude of 2 ⁇ , an initial phase angle of + and a slope.
• the lines are superimposed.
• the energy consumed by the external disturbance perturbation injection system and propagating in the network is mainly manifested by non-periodic components.
• ⁇ characterizes the magnitude and flow direction of the non-periodic component of the branch potential energy
• the present invention defines ⁇ as the energy flow direction factor.
• 3 ⁇ 4C ⁇ eo ⁇ ( ⁇ + i Po (2)
• ⁇ ⁇ is the oscillation amplitude
• ⁇ is the damping factor
• ⁇ is the oscillation angular frequency
• ⁇ % is Initial phase.
• the problem is summarized as the identification of each frequency, amplitude and damping coefficient.
• the Prony algorithm can perform parameter identification based on the sampled active power, node frequency and dominant oscillation frequency data of a group of oscillation cycles. The power amplitude, frequency oscillation amplitude, power initial phase and frequency oscillation initial phase in the dominant oscillation frequency mode are estimated. It is a good analysis method in determining the oscillation characteristics and is widely used in engineering practice.
• An object of the present invention is to provide a method for judging a source position of a forced power oscillation of a regional interconnected power grid.
• the method determines the location of the disturbance source in real time by calculating the algebraic sum of the energy flow direction factors of each region in the regional interconnected power grid.
• the invention is simple and easy to implement, and can be used as a reference for the network dispatcher to quickly find and solve faults through actual case test.
• the present invention adopts the following technical solutions: By using the real-time measurement of the low-frequency oscillation active and frequency variation of the wide-area measurement system, the Prony analysis method is used for parameter identification, and the energy of the branch is solved according to formula (5). The flow direction factor, from which the location of the disturbance source is determined.
• a method for judging a source location of a forced power oscillation of a regional interconnected power grid comprising the following steps: a. In an interconnected power grid with a wide area measurement system and an M area, an inter-area tie line branch There are £ strips on the road, and the starting and ending nodes of each tie line branch are equipped with a synchronous phasor measurement unit PMU;
• the present invention has the following advantages:
• the present invention proposes a perturbation source localization method based on calculating the energy flow direction factor, which can reduce the periodic perturbation component and the initial constant to judge the non-periodic component of the branch potential energy. Impact, with better accuracy.
• the method reduces the integral link, simplifies the calculation process, and can better adapt to the real-time calculation requirements of the power grid.
• FIG. 1 is a schematic flow chart of a method for judging a position of a forced power oscillation disturbance source in a regional interconnected power grid.
• FIG. 2 is a schematic diagram of a geographical location of a regional interconnected power grid.
• the method uses the Prony analysis method to identify the parameters of the low-frequency oscillation active and frequency changes measured in real time by the wide-area measurement system, and solves the energy flow direction factor of the branch according to formula (5), and determines the location of the disturbance source.
• This method consists of the following steps:
• the inter-area tie line branches are provided, and there is a disturbance source of periodic power oscillation in one of the areas, causing forced power oscillations in the interconnected power grid of the entire area.
• At least one end of the inter-area tie line is equipped with a PMU, and the data is synchronously transmitted to the wide-area measurement system of the power grid dispatch center.
• the active power, the frequency and the dominant oscillation frequency data collected by the wide-area measurement system are continuously transmitted to the analysis program by using one oscillation cycle as a group.
• the node; and the node ' is the starting node and the ending node of the two-zone tie line branch respectively, then need to collect the active power of the oscillation cycle of the tie line branch at either end of the tie line (such as: end) ⁇
• the frequency of the end and the dominant oscillation frequency data are continuously transmitted to the disturbance source localization analysis program.
• Disturbance source localization analysis program takes "one oscillation cycle as a group of data, and uses Prony analysis method to identify the frequency data of the active power ⁇ ⁇ and z terminals of the tie line branch ⁇ , and obtain the contact in the dominant oscillation frequency mode.
• the area where the source is located such as: the energy flow direction factor of the region E ⁇ max f? ⁇ 2 , - M , then the region E is the region where the disturbance source is located area.
• a method for judging the position of a forced power oscillation disturbing source of a regional interconnected power grid taking the 5-area interconnected power grid shown in FIG. 2 as an example to illustrate the practical application process of the present invention. Specific steps are as follows:
• the AC interconnected power grid shown in Figure 2 includes: Sl, S2, S3, S4, S5, a total of five power supply areas, respectively, through four inter-area tie lines: ml, m2, m3, m4 will SI and S3, S3 is connected to the S5, S3 and S4, S3 and S2 regions.
• the nodes at both ends of the tie line ml are il and jl, the nodes at m2 are i2 and j2, the nodes at m3 are i3 and j3, and the nodes at m4 are i4 and j4; where jl is the node in the region SI and j2 is the region
• There is a disturbance source of periodic power oscillation with an oscillation frequency of 0.62 Hz in the region SI which causes forced power oscillations in the interconnected power grid of the entire region.
• PMU devices are installed in nodes il, i2, i3, i4, and data after oscillation occurs. The data is transmitted synchronously to the wide area measurement system of the grid dispatch center.
• the threshold of the low-frequency oscillation of the wide-area measurement system needs to be satisfied at the same time: the dominant oscillation frequency is 0.1-2.5 Hz, the active power oscillation amplitude is 10 MW, and the duration is 5 cycles. When the dominant frequency of 0.62 Hz occurs in the power grid is detected. The oscillation satisfies the set threshold, that is, the low frequency oscillation alarm is issued.
• the analysis program takes 5 oscillation cycles as a set of data, uses Prony analysis method to identify the active power and frequency data of the contact lines ml, m2, m3, m4, and obtains the tie line with the dominant oscillation frequency of 0.62Hz mode.
• the contact line ml can flow direction
• the factor ⁇ 0 indicates that the oscillation energy flows from the region S1 to the region S3; 3 ⁇ 4 2: >0 indicates that the oscillation energy flows from the region S3 to the region S5; the oscillation energy flows from the region S3 to the region S4; the contact line m4 energy flow direction factor 6 Ml ⁇ 0
• the oscillating energy flows from the region S3 to the region S2.
• the region SI is the energy flow direction factor algebra and the largest region, that is, the disturbance source is located in the region S1.
• the invention can realize the rapid judgment of the location of the forced power oscillation disturbance source of the regional interconnected power grid.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Supply And Distribution Of Alternating Current (AREA)

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Citations (6)

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• 2011
  • 2011-12-01 CN CN2011103905204A patent/CN102411118B/zh active Active
• 2012
  • 2012-07-20 WO PCT/CN2012/078950 patent/WO2013078871A1/zh not_active Ceased
  • 2012-07-20 IN IN1279MUN2014 patent/IN2014MN01279A/en unknown
• 2014
  • 2014-05-20 US US14/282,755 patent/US9037425B2/en active Active

Patent Citations (6)

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