AU2009221211A1

AU2009221211A1 - Ripple control system for a supply area

Info

Publication number: AU2009221211A1
Application number: AU2009221211A
Authority: AU
Inventors: Silvan Nellen; Jurg Scheidegger; Stefan Scheidegger
Original assignee: Landis and Gyr AG
Current assignee: Landis and Gyr AG
Priority date: 2008-03-05
Filing date: 2009-02-27
Publication date: 2009-09-11
Also published as: EP2258034B1; NZ588389A; ZA201006906B; EP2258034A1; WO2009109339A1

Description

WO 2009/109339 PCT/EP2009/001423 Ripple control system for a supply area The present invention relates to a ripple control 5 system for a supply area according to the preamble of patent claim 1 and to a method for monitoring the correct reception of telegrams sent by a ripple control system in a supply area (NS) according to the preamble of patent claim 4. 10 Ripple control networks and components thereof, such as, in particular, centrally arranged ripple control transmitters, are known from the specifications EP 0 729 213 B1 [1] and EP 0 738 033 B1 [2], for 15 example. This specification uses the nomenclature according to ripple control engineering [3] in order to clear away any clarity problems from the outset. The ripple control systems used today have only a 20 unidirectional effect; a ripple control transmitter at a central location sends audio-frequency signals (telegrams) which are received by peripheral ripple control receivers for the purpose of controlling the power consumption, for connecting or disconnecting a 25 load such as boilers or street lamps. A ripple control command unit in a command center does not receive an acknowledgment of whether sent telegrams have arrived correctly at the receivers (end user) in the network. This means that faults have first been recognized and 30 reported by telephone by the customers ("end users") of the electric companies. Service engineers need to visit the reporting customer, place a meter in situ and pick it up again after a period of several days in order to evaluate the data. 35 To date, acknowledgement in line with the method indicated in figure 1 with what are known as inspection receivers has occurred only at the medium voltage level MS. The telegrams sent by the ripple control WO 2009/109339 PCT/EP2009/001423 - 2 transmitter RS are received by an inspection receiver KE and the content thereof is transmitted to a ripple control command unit RKG. This acknowledgement takes place in real time. This solution is also described in 5 detail in [3] on page 83. This acknowledgement at the medium voltage level MS does not take account of the influences on the low voltage level NS. The inspection receivers KE can be 10 connected at the low voltage level NS only to a limited extent, since they do not have any intelligence but rather merely forward the reception of a telegram and therefore require a permanent connection to a monitoring control center. 15 The present invention is therefore based on the object of specifying a ripple control system for a supply area - also called low voltage level NS - which allows monitoring of received telegrams on peripheral 20 receivers without the need for large-scale interventions in the existing infrastructure. This object is achieved by the features specified in patent claims 1 and 4. Advantageous refinements of the 25 invention are specified in the further claims. In summary, the invention has the following salient points: monitoring receivers with a transmission interface are put in a distributed arrangement at 30 selected locations in a supply area. These monitoring receivers can be connected to a monitoring control center, and telegrams buffer-stored in the monitoring receivers can be transmitted to the monitoring control center on the basis of different events. The comparison 35 in the monitoring control center with the sent telegrams allows automated recognition of faults and output of warning messages to be achieved.

WO 2009/109339 PCT/EP2009/001423 - 3 The advantage of the invention is that inspection over various points in the supply network becomes possible from the monitoring control center. The received telegrams no longer need to be evaluated in situ. 5 Furthermore, more automated transmission repetition is possible. By way of example, this allows the street lighting to be switched on belatedly or at a time later than envisaged. The connection of monitoring receivers does not require any adjustments in the supply area 10 itself. For the transmission of the received telegrams to the monitoring control center, it is possible to resort to an existing infrastructure, such as telephone network PSTN/ISDN or a mobile network GSM. This also allows unrestricted positioning of the monitoring 15 receivers in the supply area, preferably at locations at which what are known as critical conditions exist and reception interference for the audio-frequency telegrams is known or must be expected. 20 The invention is explained in more detail below by way of example with reference to the drawing, in which: figure 1 shows an arrangement of an inspection unit for the 25 acknowledgement of received telegrams from the medium voltage level in accordance with the prior art; figure 2 shows an arrangement of monitoring receivers for the 30 acknowledgement from the medium voltage level, and figure 3 shows a block diagram of a monitoring receiver. 35 Figure 2 shows the arrangement of monitoring receivers UE in a supply area NS. In accordance with the prior art, a ripple control command unit uses a substation command unit RKG-US to supply a ripple control WO 2009/109339 PCT/EP2009/001423 -4 transmitter RS with commands. The ripple control transmitter supplies these commands as audio-frequency telegrams to a medium voltage system. The coupling of the ripple control transmitter RS to the medium voltage 5 system MS is made capacitively as shown symbolically in figure 2. The medium voltage system MS itself is supplied with electrical power from a high-voltage system HS via transformers. 10 In figure 2, a low voltage system NS - also called supply area NS - is supplied with electrical power by the medium voltage system MS via a transformer. The supply area NS has loads connected to it (not shown in figure 2) which are connected or disconnected using 15 ripple control receivers RE. Specific refinements can be found in specification [3]. The monitoring receivers UE are positioned on the basis of the topology of the supply area NS. This stems from 20 the fact that damping in the low voltage system NS means that the ripple control levels of the telegrams may be very different. This type of positioning is also called distributed arrangement of monitoring receivers UE. 25 The basic components of a monitoring receiver UE are shown in figure 3. These are connected to the low voltage system and also have the same components as the ripple control receivers RE, which connect or 30 disconnect loads (not shown in figures 1 and 2) on the basis of the received telegrams. Thus, a monitoring receiver UE has a ripple control signal detector RD which transforms the received audio-frequency telegrams into a binary format. The telegrams transformed in this 35 manner are stored in a buffer store RB. Figure 3 does not show a processor system which administrates the buffer store RB and manages a filling level. The ripple control receiver RE also contains a clock, so that the WO 2009/109339 PCT/EP2009/001423 stored telegrams are preferably stored as a record in line with Table 1: - telegram content, 5 - telegram reception time, - telegram level. Table 1: Data record of the buffer store RB. 10 The monitoring receiver UE also contains a communi cation interface with an output Com. This output Com may be a serial RS232 interface, for example, to which a modem is connected which accomplishes the connection to the monitoring control center UZ. Depending on the 15 embodiment, it is possible for the modem function to be integrated in the actual monitoring receiver UE. The monitoring receivers UE preferably have the following properties: 20 - support for widely used interfaces which can easily be extended via an intermediate network; for example RS-232; - as many adapters as possible need to exist for the 25 interface, such as Ethernet, analog modem, ISDN, GSM/HSCSD; - all the ripple control codes used are supported; - buffer store or ring memory RB so that no permanent connection to the monitoring control 30 center UZ is required; - the internal clock must be accurate to the second; - software interface for reading the buffer store RB and for adjusting the internal clock of the monitoring receiver UE; 35 - level measurement: for each telegram, in addition to the bitcode and the time, the level of the starting pulse and also the average level of the address and command WO 2009/109339 PCT/EP2009/001423 - 6 pulses, and also the measured network voltage, are stored; - support for push mode: the monitoring receiver UE reports automatically 5 when a telegram has been received. A monitoring control center UZ is connected to the monitoring receivers UE. The connection provided may be PSTN/ISDN or GMS/HSCSD. The monitoring control center 10 UZ may contain a computer which performs the following functions: - Regular polling of the monitoring receiver UE and storage of the telegrams buffer-stored in the 15 buffer store of the monitoring receivers UE. - Comparison of the telegrams received in the monitoring receivers UE with the telegrams sent by the ripple control command unit RKG (a telegram may contain a plurality of commands); this is 20 possible because the reception time of the telegrams is known and the transmission time of the sent telegrams (commands) is stored in a database of the monitoring control center UZ. In this regard, the monitoring control center UZ is 25 connected to the ripple control command unit RKG, preferably via Ethernet/LAN, also called a local area network. The following modes of operation can be set for the 30 monitoring control center: Online mode As soon as the ripple control command unit RKG has sent a telegram, the monitoring receivers UE are polled in 35 online mode and correct reception is checked. If the telegram has not arrived after a particular time, the monitoring control center UZ can initiate a repeat transmission and/or an alarm message. In this way, the wO 2009/109339 PCT/EP2009/001423 operator of the network has control over the present state of the outposts and over absent telegrams and also optionally an automatic repeat transmission. The online mode is suitable for constant connection to the 5 monitoring receivers UE, which in this case are preferably connected via Ethernet. Polling mode In contrast to online mode, the monitoring receivers UE 10 are not polled by the ripple control command unit RKG after every transmission of a telegram. Instead, all monitoring receivers UE are polled in a definable interval (e.g. once a day) and a database in the monitoring control center with the received telegrams 15 and the state of the outposts is tracked. This allows the customer to perform quality control and to evaluate the monitoring data without needing to travel to the regions in which faults occur. The polling mode is suitable for tariffable dial-up connections to the 20 monitoring receivers UE, which are connected via a modem or at the outside via GSM. Hybrid mode The hybrid mode is a mixed mode comprising the online 25 and polling modes described above. The idea is that the monitoring receivers UE are accessed basically in polling mode in definable time intervals, e.g. for reasons of cost. However, it is additionally possible to determine particularly important telegrams for the 30 online mode. These are retrieved immediately after sending. Push mode The idea with this mode is that the monitoring receiver 35 UE automatically reports to the control center when a certain event has occurred. By way of example, the receiver could transmit data to the monitoring control center UE for each telegram received or when the WO 2009/109339 PCT/EP2009/001423 - 8 internal buffer store RB is full. This mode requires additional intelligence in the monitoring receiver UE or the converter: it must be capable of addressing a modem in order to set up a connection to the control 5 center. In addition, the monitoring receiver UE must be able to react to the situation in which the monitoring control center UZ is unavailable (for example because another monitoring receiver UE has set up a connection). These additional functions require the use 10 of an intelligent component (for example an embedded system). In addition to the exemplary embodiment of the present invention described previously, it may make sense to 15 continue the monitoring practiced in line with the prior art on the medium voltage system MS in parallel therewith. It is likewise possible to integrate the function of 20 the monitoring control center UZ and the function of the ripple control command unit RKG in a single unit; this is a further advantageous embodiment of the present invention.

WO 2009/109339 PCT/EP2009/001423 - 9 List of reference symbols and abbreviations used Com Communication link GSM Global system for mobile communication 5 HS High-voltage system HSCSD High speed circuit switched data; GSM ISDN Integrated services digital network MS Medium-voltage system KE Inspection receiver 10 LAN Local area network, Ethernet NS Low-voltage system; supply area PSTN Public switched telephone network RKG Ripple control command unit RKG-US Substation command unit 15 WT AC telegraphy unit RB Ring buffer RD Ripple control telegram detector RE Ripple control receiver RS Ripple control transmitter 20 UE Monitoring receiver UZ Monitoring control center WT AC telegraphy unit WO 2009/109339 PCT/EP2009/001423 - 10 List of cited literature [1] EP 0 729 213 B1 Arrangement having a ripple control transmitter and a network interface connected downstream of 5 the ripple control transmitter Siemens Schweiz AG, CH-8047 Zurich [2] EP 0 738 033 B1 Ripple control system 10 Siemens Schweiz AG, CH-8047 Zurich [3] Ripple control engineering Paessler, Enrst-Robert Publicis MCD Verlag, Erlangen 15 VWEB erlags- und Wirtschaftsgesellschaft der Elektrizitatswerke m.b.H.; Frankfurt/Main ISBN 3-89578-004-9 ISBN 3-8022-0414-X

Claims

1. A ripple control system for a supply area (NS), wherein the ripple control system has: 5 - a ripple control command unit (RKG) which is coupled to a ripple control transmitter (RS), wherein the ripple control transmitter (RS) supplies telegrams sent by the ripple control command unit (RKG) as audio-frequency signals to 10 the supply area (NS); characterized in that the ripple control system additionally contains the following: - the supply area (NS) contains monitoring receivers 15 (UE) in a distributed arrangement which receive sent audio-frequency telegrams and buffer-store them in a buffer store (RB); - a monitoring control center (UZ) which can be connected to the monitoring receivers (UE) in 20 order to receive the telegrams buffer-stored in the monitoring receivers (UZ) and to compare them with the telegrams sent by the ripple control command unit (RKG). 25

2. The ripple control system as claimed in claim 1, characterized in that the ripple control command unit (RKG) is connected to the monitoring control center via a local area network (LAN). 30

3. The ripple control system as claimed in claim 1 or 2, characterized in that the buffer store is in the form of a ring buffer store 35 (RB) and in that the monitoring receiver contains a processor system which administrates the ring buffer store. WO 2009/109339 PCT/EP2009/001423 - 12

4. A method for monitoring the correct reception of telegrams sent by a ripple control system in a supply area (NS), wherein the ripple control system has: - a ripple control command unit (RKG) which is 5 coupled to a ripple control transmitter (RS), wherein the ripple control transmitter (RS) supplies telegrams sent by the ripple control command unit (RKG) as audio-frequency signals to the supply area (NS); 10 characterized in that - the supply area (NS) contains monitoring receivers (UE) in a distributed arrangement which receive and buffer-store sent audio-frequency telegrams; - a monitoring control center (UZ) which can be 15 connected to the monitoring receivers (UE), and the telegrams buffer-stored in a buffer store (RB) in the monitoring receivers (UZ) are transmitted and are compared with the telegrams sent by the ripple control command unit (RKG). 20

5. The method as claimed in claim 4, characterized in that the transmission of the buffer-stored telegrams is initiated by the monitoring control center (UZ). 25

6. The method as claimed in claim 4, characterized in that the monitoring receivers (UE) are permanently connected to the monitoring control center (UZ) and in that the 30 buffer-stored telegrams are transmitted immediately after reception thereof.

7. The method as claimed in claim 4, characterized in that 35 the transmission of the buffer-stored telegrams is initiated by the monitoring receivers (UE).

8. The method as claimed in claim 7, WO 2009/109339 PCT/EP2009/001423 - 13 characterized in that the transmission of the buffer-stored telegrams is initiated on the basis of the filling level of the buffer store (RB) situated in the monitoring receiver 5 (UE).

9. The method as claimed in one of claims 4 to 8, characterized in that the buffer store (RB) of the monitoring receiver (UE) 10 is used to store the following data: - telegram content, - level of the received telegram, - time of reception of the telegram. 15

10. The method as claimed in one of claims 4 to 9, characterized in that the function of the monitoring control center (UZ) and the function of the ripple control command unit (RKG) are integrated in a single unit.