Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
  • G01R11/02—Constructional details
  • G01R11/24—Arrangements for avoiding or indicating fraudulent use
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
  • G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods

Definitions

• the invention is related to the field of electrical engineering, that is, a device designed for accounting of electric power in single-phase and three-phase power consumer networks.
• Electric meters that are used for electricity billing; electric power counters (induction-type and electronic) are in service for decades.
• electric power counters induction-type and electronic
• the creators and designers thereof are mainly focused on the precision of measurements, and the durability, reliability and price of the device.
• FIG.l I' and 2' the main units of the device -electric magnets; 3' - aluminium disk that turns on a pivot; 4' — pivot supports - bearings; 5' and 6' - constant magnet; 8' - pinion connecting the pivot and the counting mechanism; 9' — antipole of electric magnet 1'.
• the purpose of the invention consists in the creation of a tamper-proof electricity meter maximally protected from illegal use of electric power by way of tampering with the meter's readings for the benefit of the consumer. To this end a device has been created using complex technical and designing solutions the details of which are presented below.
• An electricity accounting device presented herein consists of a single-phase and three- phase electricity meter connected to an automatic switch wired to a phase or zero mains conductor that is led to the electricity meter's terminal 1 (e.m.) (e.m. means an electricity meter) by leading the conductor via the current-voltage transformer, whereas terminal 1 (e.m.) is connected via the electric meter's current coil to the electricity meter's terminal 3 (e.m.) that is wired to terminal 3 of the user terminal block, which terminal is connected to terminal 3a wired to connector I of user P, and, connector II returning from user P is wired to terminal 4a of the user terminal block and is further led via terminal 4 to the electricity meter's terminal 4 (e.m.), from where it is led via terminal 2 (e.m.) to the automatic switch by passing through the current-voltage transformer in the direction opposite to that of the lead coming from the automatic switch; besides, the magnetic conductor has a secondary voltage coil both ends of which are wired to the rectif
• Terminal 1 (e.m.) is wired to the voltage terminal of the electricity meter's coil via temperature relay TR.
• Automatic switches are used before the electricity meter for user connection to the power supply network in accordance with the normative documents of lead-in equipment. They control the overload of the power supply network and the electricity meter, and protect the power supply network from the user's equipment short circuit currents. The above mentioned protection measures are insufficient seeking to protect electrical power from illegal use (theft).
• One of the popular methods of electrical power theft consists in connection of an additional zero to the user terminal load.
• User connection circuit diagram Fig.3 represents the traditional type of a circuit used by power supply companies and corresponding to the electricity meter design. Electricity is illegally used by way of additional wiring to earth or zero. It is noticeable from Circuit diagram Fig.3 and Circuit diagram Fig.4 that in order to avoid illegal flow of electricity ⁇ i through the electricity meter by-pass wiring, current I f incoming via the user is subject to check-up (which is effected in the modern electricity meters) and current I 0 returning to the mains from the user via the operating zero conductor shall be subject to additional check-up.
• the device is designed for use at the electricity user connection lead-in before electricity meters in combination with automatic commutation switches that already incorporate short circuit control and thermal protection against the equipment and mains overload. It is intended to monitor load current I f coming to the user and the current returning from the user in a single-phase or three-phase power supply system, by method of comparison at the lead-in. This method is used to determine the absolute value ⁇ i of
• I f - I 0 . When the equipment is in good order (which is a must in the operation of electrical power networks), ⁇ i 0 (according to Kirchhoff s law). This method enables to supervise whether or not the user has mounted an additional zero connection after the load resistance. Value ⁇ i ⁇ O shows that the user connection and accounting circuit 1 have been tampered with.
• Electricity meters read zero if the user breaks the zero a conductor in an inconspicuous place in Circuit diagram Fig.5, and uses additional earthing.
• the energy induced by ⁇ i is transferred into the mechanical energy by an electrical magnet which energy is sufficient to enable mechanical cutout of an automatic switch via a sensitive mechanical cutout module mounted on the automatic device, if the difference of currents I f and I 0 reaches the preset limit due to the fact that the accounting device has lost the potential difference necessary to keep it functional.
• the zero conductor is disconnected before the electricity meter, whereas the user/consumer makes an attempt to use electrical power by wiring its load to the phase and additional zero conductors, i.e. attempts to consume electricity without accounting.
• the value of A 1 coordinated with the power supplier must not exceed the amount corresponding to a 40 W load.
• the above-mentioned method enables complete prevention of illegal consumption/theft of electrical power via accounting device by-pass channels because it disables the most popular and safe way of power theft.
• circuit diagram Fig 9 which is extended circuit diagram of circuit diagram Fig. 8:
• An automatic switch is mounted by breaking the phase conductor.
• the function of reducing the risk of overload in the connection cables, the electricity meter and the power supply network (and thereby the risk of damage to the network characteristics), the risk of meter burning and the risk of fire will be effected only when the automatic switch is mounted on the phase conductor (see circuit diagram Fig.10).
• a three-phase automatic switch is used in a three-phase system. If the phase and zero conductors of the lead-in before the LMB (Lead-in Meter Board) are mixed up intentionally or unintentionally (e.g. during power line repairs), then the current consumed by the user will flow through the electricity meter's zero terminal 2(e.m.), 4(e.m.), i.e. alongside the electricity meter's current coil, i.e. alongside the accounting device of the electric meter, if the user intentionally or unintentionally applies the additional zero. Thus, the switching conductors, the electricity meter and the network characteristics are left unprotected and the risk of fire is increased, thus leading to violation of Item 3.3.7 of the Regulations (see circuit diagram Fig.l 1).
• Such interchange of the conductors (f and 0) before the LMB is also popular with the illegal users of electrical power.
• Using two single-pole automatic switches is recommended in a double-conductor power supply system, i.e. by breaking each of the phase and zero conductors, or using one double-pole switch. See circuit diagrams Fig.12 and Fig.13. hi a double-conductor power supply system two breakers are used on both conductors (Circuit diagram Fig.12) instead of one automatic phase breaker, or one double-pole breaker (Circuit diagram Fig.13). Switching of a commercial accounting device, i.e. a single-phase electricity meter to a power supply network is offered to be effected not through one, but through two automatic break switches.
• An electricity meter is a device that reacts to both the quantity of electricity consumed and the direction of its flow. This property of the electricity meter to react to the direction of power transfer requires mandatory matching of the current and voltage parts of the meter in the course of switching so that the disk turns in the direction shown by the arrow during power consumption by the user (in the case of an induction-type electricity meter) and the readings change by way of increase (in the cases of both induction-type meter and electronic meter).
• Terminal 1 of the current coil corresponds to its beginning, whereas terminal 3 corresponds to the end of the coil.
• the phase power supply conductor must be led to supply terminal 1
• the power supply zero conductor must be led to terminal 2 of the zero block.
• Conductors passing from the electricity meter to the user must be switched to terminal 3 (load terminal) corresponding to the end of the current coil, whereas the other conductor must be switched to terminal 4 of the zero block.
• the voltage circuit switching terminal in electricity meters is always next to the terminal corresponding to the beginning of the current coil, and in the electricity meters is directly connected to the current terminal by means of a terminal jumper.
• USB User Switching Block
• This enhancement enables to avoid any potential error in the user switching to the mains and any intentional tampering with the meter's switch-block wiring without the knowledge of the manufacturer, which may cause electricity meters to underread the data to the personal benefit of the user.
• the mains and user conductors are wired indirectly to the meter's switch-block.
• the mains conductors f(0) and 0(1) are wired to automatic breakers Al and A5, i.e. the user is switched through an additional switching block USB.
• the user switching-electricity meter input terminals (Al and A5) and the electricity meter output terminals (USB) in circuit diagram Fig.15 are visually different and are laid out at a sufficient distance from each other thus enabling to avoid a possible confusion thereof.
• the connector has no direct access to the meter's terminal block (thus removing the possibility of confusion of the conductor f incoming from the network and the conductor outgoing to the user, and thereby removing the possibility of reversing the load current), thus creating a technical possibility of preventive limitation of illegal consumption of electrical power.
• the electricity meter, the two automatic breakers, the watchdog module and the user switching block are wired on the board by mechanically inseparable connections.
• the electricity meter, the two automatic breakers, the protection module and the user switching block are inseparably mounted and interconnected on a single additional panel leaving the possibility to replace the automatic breakers with the ones of another desired rating without the manufacturer's intervention.
• this structure could enable to avoid errors that may occur in the case of switching an electricity meter after confusing the power supply and the load conductor switching terminals, and conductor f and 0 switching terminals, which also creates conditions for illegal use of electrical power.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Remote Monitoring And Control Of Power-Distribution Networks (AREA)
• Breakers (AREA)
• Keying Circuit Devices (AREA)

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Citations (4)

• 2006
  • 2006-06-13 LT LT2006048A patent/LT5473B/lt not_active IP Right Cessation
• 2007
  • 2007-01-04 WO PCT/LT2007/000001 patent/WO2007145498A1/en active Application Filing

Patent Citations (4)

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