FR2513767A1 - Power over-stepping controller for electricity system subscriber - has sealed unit containing fuse with breaks when excess power is taken over pre-set time duration - Google Patents

Abstract

A measuring circuit supplies a measuring signal (SM) representing the strength of the current consumed by the installation. It also comprises a control circuit which receives the measuring signal and produces an opening command signal if the current strength exceeds a predetermined threshold , the threshold corresponds to the rating of the circuit breaker. This signal causes the circuit breaker to open. If the current strength remains above the predetermined threshold the control circuit produces an overstep registration command signal A fuse is connected to the control circuit and blows in response to the overtop registration command signal. The measuring circuit, control circuit and fuse are all contained in the sealed meter box.

Description

OVERFLOW CONTROL DEVICE

  ELECTRIC POWER SUBSCRIBED BY A SUBSCRIBER.

  The subject of the present invention is a provision

  monitoring of excess electrical power

  than subscribed by a subscriber for an installation

  usually taking a meter fitted with a sealed housing and a circuit breaker.

  Electricity pricing, in particular

  link the subscription amount, depends on the

  power subscribed by the subscriber, i.e. from the

  maximum available power mite depending on the-

  which the circuit breaker is normally calibrated For an electricity distribution company, the revenues linked to the subscribed powers represent a share

  notable of total resources It is therefore particularly

  important to be able to ensure compliance

  setting the circuit breakers with the subscribed powers

  because we know that circuit breakers are not

  always correctly calibrated and sometimes

  trick of fraud difficult to detect Now, in most domestic installations, circuit breakers are

  installed at the subscriber's premises while the meters are

  outside wind This provision, if it facilitates the recording of consumption, however makes practically impossible the control by the agents of the distributing company of the accuracy of the adjustment of the caliber of

circuit breakers.

  Also, the present invention aims to

  provide a device to control overage

  the contract power due to a function-

  defective or circuit breaker fraud, without

  that it is necessary to access the latter.

  This object is achieved by means of a device comprising: a measurement circuit supplying a measurement signal representing the intensity of the current consumed by the installation; a control circuit receiving the signal from

  measuring and producing a recording command signal

  overshoot when said intensity remains above a predetermined threshold corresponding to the rating

  of the circuit breaker, for a period longer than that

  quise for opening the circuit breaker, and an overflow recording element

  connected to the control circuit and whose state is

  irreversibly changed in response to the com-

  overshoot recording command, the measuring circuit, the control circuit and the overshoot recording element being accommodated

  in the sealed meter housing.

  Thus, the circuit breaker control can be carried out by the agents of the distribution company.

  electricity at the same time as the statement of consumption

  with only access to the meter, and any intervention on the control device requires

  opening the meter housing.

  Advantageously, the control device further comprises u N fault current generator circuit reacting to an opening control signal to cause the opening of the circuit breaker and the circuit.

  command produces said opening signal, when the

  said intensity has exceeded the predetermined threshold, and said overshoot recording control signal with a delay of predetermined duration relative to the opening control signal, in case said intensity is always greater than the predetermined threshold at expiration

of this duration.

  Thus, it is no longer necessary to make sure of the correct calibration of the circuit breaker as a function of the subscribed power, but only of the correct functioning of the circuit breaker in response to the fault current generated. of the counter (setting the control circuit threshold), the circuit breaker retaining only its "safety" function. Advantageously also, for an installation in which the meter comprises an electromagnet

  current with a winding traversed by the current consumed

  mé in the installation, the measurement circuit includes a sensor constituted by an auxiliary winding on the current electromagnet Furthermore, the meter comprising a voltage electromagnet with a winding connected in parallel on the conductors supplying the installation, power supply for the overshoot control device is obtained from a

  voltage supplied by an auxiliary winding on the electric

tension magnet.

  So current measurement and power

  of the device can be carried out in an extremely

  simple, and it has been shown that the windings

  do not significantly change the

  counter trology, contrary to what we have

couldn't wait.

  Other features and advantages of the

  positive control according to the invention will emerge at the

  reading of the description given below, as an indication

  catif but not limiting, with reference to the drawings an-

  attached to which FIG. 1 is a block diagram of an embodiment of the control device according to the invention, FIG. 2 illustrates in more detail one mode

  of the control circuit of the control device.

Figure 1, and,

  Figure 3 is a diagram of the il-

  polishing the operation of the control circuit

Figure 2.

  In Figure 1, are schematically represented

  felt the counter I and the circuit breaker 2 of an installation

  Subscriber connection connected to a distribution network by terminals 3, 4 In general, the counter I

  is housed in a sealed housing and includes an electro-

  current magnet 5 with a coil 5 a connected between one (3) of the connection terminals and a terminal 3 a connected to an input of the circuit breaker 2, a voltage electromagnet 6

  with a coil 6 a connected in parallel between the terminals

  nes 3, 4 and a rotating disc 7 passing between the electro

  three magnets 5 and 6 The circuit breaker 2 is of the different type

  rentiel It has two input terminals 8 a, 9 a connected to terminals 4 and 3 a and two output terminals 8 b, 9 b connected to the subscriber's installation The opening of the circuit breaker occurs when a current flowing between an input, for example 8 a, and the corresponding output 8 a

  intensity which differs from that of the current flowing

  be the other input 9 a and the other output 9 b of a quantity -

  tee greater than a given threshold, generally 500 m A. The control device 8 for exceeding the subscribed power comprises a measurement circuit 10 which supplies a measurement signal SM representative of the intensity IC of the current consumed by the installation,

  a control circuit 20 which provides a control signal

  opening command SCO when the measurement signal has exceeded a predetermined threshold and which provides an SED overshoot recording control signal when the measurement signal remains above the threshold after the end of the opening control signal, a circuit 40

  fault current generator which causes the opening-

  re of the circuit breaker in response to signal SC 0, an overshoot recording circuit which irreversibly records an overshoot of subscribed power in response to the SED signal and a supply circuit

  which supplies the necessary supply voltage (s)

  for the operation of the various circuits 10,

, 40 and 50.

  The measurement circuit 10 comprises a sensor II advantageously constituted by a copper coil placed on the current electromagnet 2 of the counter I of

  so as to be traversed by the magnetic flux flowing through it

  the magnetic circuit of this electromagnet The voltage

  induced in the coil It is applied to an input

  12 a of a differential amplifier 12, the other of which

  trée 12 b is connected to ground by a resistor 13.

  A first diode 14 is connected directly between the

  output of amplifier 12 and one terminal of a conden-

  sator 15 whose other terminal is grounded A second-

  the diode 16 is connected in reverse between the output of the amplifier 12 and the input 12 b of the latter This input 12 b is connected by a resistor 17 to the common point 18 between the diode 14 and the capacitor 15 Ce

  common point is the output terminal of the measurement circuit

  re 10 o is available the measurement signal SM.

  The control circuit 20 comprises a compa-

  generator 21, a generator 25 of clock pulses and a circuit 30 for developing control signals

  SCO opening and SED overrun record.

  The comparator 21 comprises a differential amplifier, one input 21 a of which is connected to the output terminal 18 of circuit 10 and the other input of which 21 b is connected to the midpoint of a voltage divider formed by two resistors 22, 23 connected in series between earth and a + V terminal brought to a reference potential The resistor 22 is adjustable so as to adjust the voltage at the input 21 b to a predetermined threshold value VS A resistor 24 e S tbra N ch é e

  in reacticn eiare 'a borr e de -ortie 21 S of the ampli-

  ficitor 21 and its input 21 b The voltage on the terminal

  21 S output level changes when the signal

  sure SM exceeds the threshold value VS This change in

  level constitutes the SD overshoot signal.

  The clock pulse generator 25 uses

  reads a winding 61 wound on the electromagnet

  sion 6 of the counter I and of which a terminal 61 a is connected by a resistor 26 to a shaping circuit 27 which converts the ripples of the voltage present on the terminal 61 a into rectangular pulses of the same frequency This circuit 27 comprises a door Pl whose

  inputs are connected in common and connected to the resistor

  26 and whose output constitutes the output of the general

  25, and a Zener Zi diode connected between the mas-

se and the entrances to the gate Pl.

  The circuit 30 for generating signal signals

  control includes a timing and counting circuit 'having a counting input 30 a which is connected to the output of the generator 25 and a validation input 30 z

  connected to the output of comparator 21 The com-

  SCO opening command is produced, for example in the form of a calibrated pulse, on an output 30 d of a shaping circuit 30 "which is connected to circuit 30 'of

  timer and counting Similarly, the

  SED overrun record command general

  e S t p r o d u i t S u r u N e S o r t i e 30 m d u c i r -

  c u i t c o N f o r m a t e r 30 "U N m o d e particu-

  link of realization of the circuit 30 of elaboration of the

  general control will be described later in detail in

reference to Figures 2 and 3.

  The fault current generator circuit 40 includes a relay 41 whose fixed and movable contacts form a switch 42 connected in series with a resistor 48 between an input terminal, for example 8 a, of the circuit breaker 2 and the opposite output terminal 9 b The

  excitation coil 43 of relay 41 is connected in se-

  rie with a resistor 44 between a supply terminal

  tion and the collector of a transistor 45 The emitter of transistor 45 is connected to ground and its base is connected to the output 30 d of the 30 "circuit via a

  resistor 46 A protective diode 47 connects the mas-

  at the common point between the resistor 44 and the coil 43. The overflow recording circuit 50 comprises a thyristor 51 whose control electrode (trigger) 51 a is connected to the 30 m output of the 30 "circuit by the intermediate of a resistor 52 The thyristor 51 is connected on one side to a supply terminal by a resistor 53 and, on the other side, to ground by

  a fuse 54 A diode 55 connects the base of a transis-

  tor 56 at the common point between thyristor 51 and fu-

  sible 54 The transistor 56 has its collector connected to a

  power supply terminal by a resistor 57 and its emitter-

  tor connected to ground by a light-emitting diode 58 A resistor 59 is connected in parallel on the series circuit formed by the resistor 57 and the collector-base junction of the transistor 56, Finally, the supply circuit 60 comprises

  a voltage doubler connected to the terminals of the winding-

  ment 61 crossed by the magnetic flux traversing the

  magnetic circuit of the electromagnet voltage 6 of the comp-

  The tension doubler provides a tension

  sufficient power to supply the circuits of the

  while limiting the number of turns around the

bearing 61.

  As an indication, the voltage induced in the winding can have an amplitude of the order of 15 Veff. The voltage doubler comprises, as known per se, a polarized capacitor 62 whose negative plate is connected to terminal 6 Ia of the winding 61 and the positive plate of which is connected to the cathode of a first diode 63 and to the anode of a second diode 64 The other terminal 61 b of the winding 61 is grounded as well as

  the anode of diode 63 and the negative plate of a

  polarized densifier 65 whose other plate is connected to

  the cathode of diode 64 The supply voltage re-

  line supplied by circuit 60 is available across capacitor 65 and has an amplitude of approximately V. This voltage and, if necessary, one or more predetermined fractions thereof, are used

  to supply the different circuits 10, 20, 40 and 50.

  Circuits 10, 20, 50 and 60 are housed inside the sealed housing of meter 1, housing

  shown schematically in Figure 1 by a line in mixed lines-

  tes Circuit 40 can also be housed indoors

  laughter of this box, as in the example illustrated, the connection with the circuit breaker being carried out by a line

  bifilar 49 The light-emitting diode 58 is available

  located behind a transparent cover on the front face of the meter housing 1 so that its on or off status can be checked without it being necessary

to open the case.

  The operation of the control device

  overshoot described above is as follows We rgfi-

will always be shown in Figure 1.

  The tension induced in the turn It is amplified

  connected and rectified by amplifier 12 and diodes 14, 16 to supply a measurement voltage SM having an amplitude proportional to the intensity IC of the current

consumed in the installation.

  Via resistor 22, the

  comparator threshold value 21 is preset to a ni-

  calf as a function of the power subscribed by the subscriber so that the amplitude of the voltage SM crosses the threshold VS when the intensity IC of the current consumed has

  exceeded the nominal current IN corresponding to the

  subscribed, for example when IC> 1.2 IN.

  As long as the measurement signal SM remains below the threshold VS, the voltage at the output of the comparator 21 is at the low level The operation of the counting circuit is inhibited and the voltages on the outputs 30 d, 30 m are at the low level The transistor 45 is blocked, no current flows in the coil of relay 41 and the switch 42 remains open Furthermore, the thyristor 51 is not

  tripped and fuse 54 holds the base of the transis-

  tor 56 at a potential such that this transistor is blocked

  and the diode 48 is not supplied.

  When at an instant t the amplitude of the signal O

  measurement signal SM exceeds the threshold VS, the signal for exceeding

  SD appears at output 21 S of comparator 21 (step-

  output voltage from low level to high level) The signal SD c o m m a N d 1 1 d é m a r r a g of f o N c t i o N N e m e N t ducircuit 30 d elaboration de

control signals.

  If at time t 1 = t + T the signal of me-

  sure is back below the VS threshold, circuit 30 stops working and no SCO or SED signal is emitted. Note that the resistor 24 'b r a N c hé e e n

  reaction between output 2 is and input 21 b of the compa-

  rator 21 adjusts the hysteresis of this comparison

  the value of the difference between

  the initial threshold VS which the measurement signal must reach

  on SM to cause the appearance of the fault signal

  pass SD and the value slightly lower than VS below which the signal must then go back down

  SM measurement to cause the SD signal to disappear.

  If, on the other hand, at time t 1 = to + T 1, the measurement signal is always greater than the threshold of the

  comparator, the underpower is exceeded

  and the 30 "channel is controlled so as to pro-

  reduce on its output 30 a calibrated pulse of predetermined duration t As an indication, one can choose for T 1 a value of the order of 2 S and for t a value of

around 100 ms.

  The calibrated pulse produced on the output d constitutes the signal SCO This pulse causes the

  conduction of transistor 45 and therefore the closing

  ture of the contacts 42 of the relay 41 A fault current is thus generated during the duration of the SCO pulse, current whose intensity is limited by the resistor 48 to a value for example of approximately I A.

  Normally, this fault current should provo-

  quer the opening of the circuit breaker No more current flows in the installation and the SD signal disappears,

  which interrupts the operation of circuit 30.

  In the event of a breakdown or fraud resulting in non-opening, the circuit 30 continues to operate

  and, at time t 2 = t 1 + T 2, the 30 "circuit is controlled

  dg so that the voltage on its output 30 m goes to the ni-

  high calf and thus generates the SED signal The thyristor 51 is triggered and driven, which causes the fuse to blow 54 The transistor 56 is then saturated by the resistor 59 and a current flows in its emitter-collector circuit causing the final ignition of the light-emitting diode 58 The duration T 2 is by

  example of around 2 s Note that the 55 LED diode

  chée in reverse between thyristor 51 and transistor

  56 allows the blocking of thyristor 51 which, otherwise, conti-

  would harm to drive through transistor 56 and the

  light-emitting diode 58 to ground.

  Alternatively, the fuse 54 can be replaced

  placed by the base-emitter junction of a transistor, junction whose destruction is easier than that

of a conventional fuse.

  Diode 58 being visible on the front face of the

  meter housing, its ignition is immediately off

  concealed by the person responsible for recording consumption.

  The housing of the control device circuits

  the inside of the sealed meter housing does not allow

  undetectable fraud aimed at preventing the ignition of the

light emitting diode.

  Note that the copper coil Il and the winding

  Lement 61, not only constitute very simple means for taking a signal representing the intensity of the current consumed and taking the energy necessary to supply the circuits of the control device, but moreover, do not affect the metrology of the meter.

  sensibly, as has been verified.

  Finally, an additional advantage of the arrangement

  tif of control lies in the fact that it is used

  ble with existing RCDs without

  modification of these, and that it is no longer even necessary

  be concerned with adjusting the caliber of devices

  trunks according to the subscribed power, this

  glage being effected by the resistor 22 housed in the

meter housing.

  Reference will now be made to FIG. 2 which illustrates in detail a particular embodiment of the circuit 30 for developing the SCO control signals.

and SED.

  Circuit 30 includes two frequency dividers.

  quence 31, 32 produced in the form of counters so

  to divide the frequency of the clock pulses 25 res-

  pectively by 100 and by 5 The counter 31 has its counting input connected to the output of an AND gate 33, the two inputs of which are connected respectively to the input 30 a and to the output 31 S of the counter 31 The counters 31 and 32 have reset terminals 31 z and 32 z connected to the outputs of two doors OR 34, 35 with two inputs La

  OR gate 34 has an input connected to input 30 z by the

  term 9 diary of an inverter 36 and the other connected input

  at the output 32 S of the counter 32 The OR gate 35 also has

  a first input connected to the output of the invert-

sister 36.

  The shaping circuit 30 "comprises a flip-flop 37 whose input D is at the high logic level (1), whose input H is connected to the output 31 S of the

  counter 31 and whose reset Z terminal is re-

  linked to the output of the inverter 36 Two AND gates 38, 39 have first inputs connected to the output 31 S of the

  counter 31 and second connected inputs respectively-

  ment to outputs & and Q of flip-flop 37 Output Q is also connected to the second input of the OR gate The outputs of doors 38, 39 constitute the outputs

  30 d and 30 m o are produced the signals SCO and SED.

  The operation of the circuit 30 described below

  above is the following (we will also refer to the fi-

  gure 3) After exceeding the power subscribed to

  at time t, the signal SD on terminal 30 z passes from the ni-

  low calf at high level (line a in figure 3)

  counters 31, 32 and rocker B are released by the

  inverter 36 The counter 31 counts the

* pulses of frequency equal to 50 Hz produced by the clock-

  slot 25 (Figure 3, line b) and, at the 100th pulse, that is to say after 2 s, the output 31 S of the counter

  31 goes high at time t 1 (Figure 3, line c).

  The AND gate 33 then lets the pulses of

  clock 25 to counter 32 whose output 32 S does not

  in turn high at the 5th impulse received (fi-

  gure 3, line d) The output signal from counter 32 pro-

  here resets counter 31 to zero via OR gate 34 A 100 ms pulse was thus created at output 31 s This pulse crosses AND gate 38, validated by output Q (figure 3, line f ) of the

  flip-flop 37, to constitute the SCO signal (Figure 3, li-

  gne g) The output pulse of counter 31 is also

  lemeàt applied to the entry H of rocker 37, it

  causes its rear edge to tip over

  ci, from where the levels on the Q and Q outputs change (figure 3, lines f e) It follows the blocking of the

  gate AND 38, the resetting of counter 32 by the

  OR gate 35 and validation of the

gate AND 39.

  If the circuit breaker operates in response to the

  general SCO, the SD signal returns to the low level causing

  re-initialization of the entire system.

  If, as a result of a technical fault or fraud, the circuit breaker has remained on, the

  counter 31 continues to count the clock pulses

  accommodates 25 and the output 31 S of this counter will go back to the ni-

  high calf after 2 s, at time t 2 (Figure 3, li-

  gne h) This signal at the output of counter 31 is transmitted through the AND gate 39 and constitutes the signal SED on

  the output 30 d Due to the blocking of the counter 32, the du-

  SED signal can exceed 100 ms, and reach a value at most equal to 2 s Blocking of the AND gate 38

  prevents a new circuit breaker command which could

  could damage the resistor 48 traversed by the

  rant of fault It will be noted that the appearance of the signal SED takes place exactly 2.1 S after the appearance of the signal SCO which has a delay of 2 S compared to the appearance

of the SD signal.

Claims (7)

CLAIMS I Control device for exceeding electrical power subscribed by a subscriber for an installation comprising a meter (1) provided with a sealed housing and a circuit breaker (2), device characterized in that it comprises a circuit measurement (10) providing a measurement signal (SM) representing the intensity (IC) of the current consumed by the installation, a control circuit (20) receiving the measurement signal (SM) and producing a signal of overshoot recording command (SED) when said intensity (IC) remains above a predetermined threshold (VS) corresponding to the rating of the circuit breaker (2), for a duration greater than that required to open it of the circuit breaker (2), and, an overshoot recording element (54) connected to the control circuit and whose state is irreversibly changed in response to the overshoot recording control signal (SED) , the measurement circuit (10), the control circuit (20 ) and the overflow recording element (54) being housed in the sealed meter housing (1).   2 Device according to claim 1, characterized in that it further comprises a circuit (40) fault current generator reacting to an opening control signal (SCO) to cause the opening of the circuit breaker (7), and in that the control circuit (20) produces said opening signal (SCO)   when said intensity (CI) has exceeded the pre-   determined (VS) and produces said command signal to   overshoot registration (SED) with a delay of   predetermined time in relation to the opening control signal (SCO) in case said intensity (IC) is   always above the predetermined threshold at expiration tion of this duration.   3 Device according to any one of the res-   dications I and 2 for an installation in which the counter (1) comprises a current electromagnet (5) with a winding (5 a) traversed by the current consumed in the installation, characterized in that the measuring circuit (10) comprises a sensor (11) constituted by an auxiliary winding on the current electromagnet (5).   4 Device according to any one of the res-   dications 1 to 3, for an installation in which the meter (1) comprises a voltage electromagnet (6)   with a winding (6 a) connected in parallel to the con- ductors supplying the installation,   characterized in that the power supply of the device   positive overshoot control is obtained from a voltage supplied by an auxiliary winding (61)   on the voltage electromagnet (6).   Device according to any one of claims 1 to 4,   characterized in that it includes a comparator (21)   receiving the measurement signal (SM) and producing an overshoot signal (SD) as long as the predetermined threshold is exceeded, and a timing and counting circuit (31) the operation of which is authorized for the duration of the overshoot signal (SD) to control the development of an opening control signal (SCO) of the circuit breaker   (2) and the overshoot recording control signal   ment (SED) respectively when a first and a   cond predetermined time interval has elapsed since the instant the measurement signal (SM) reached said threshold.   6 Device according to any one of the res- dications I to 5,   characterized by the fact that the recording element of   passing is a fuse (54) destroyed by the signal   overshoot recording command (SED).   7 Device according to any one of the res- dications 1 to 5,   characterized in that the dg- recording element   passement is a transistor whose junction is dg-   trout by the recording control signal from of overflow.   8 Device according to any one of the res-   dications 1 to 7, characterized in that it includes an indicator member   overrun (58) operating in response to change-   status record element (54)   pass to provide an indication of overshoot   visible on the outside of the meter case (1).   9 Device according to claim 2 for an installation provided with a differential circuit breaker (2), characterized in that the fault current generator (40) comprises a switch circuit (42) having two contacts connected respectively to an input conductor (8 a) of the circuit breaker and an output conductor (9 b)   opposite to that of entry, and having a terminal of com-   command connected to the control circuit (20) so as to cause the closure of the contacts (42) in response to the   opening control signal (SCO).