MXPA00001758A - Modular protective relay with submodules - Google Patents

Abstract

A protective relay having internal processing circuitry embodied by removable and replaceable modules. Each module includes a main circuit board having common circuitry and also includes removable and replaceable submodules which electrically connect with the main circuit board to perform specific functions. The protective relay can have its functions altered by replacing one or more modules or submodules.

Description

MODULAR PROTECTOR RELAY WITH SUB-DIVES FIELD OF THE I NVEN C ION The present invention relates to protective relays. More particularly, the present invention relates to protective relays that include interchangeable parts. BACKGROUND OF THE I NVENTION Protective relay devices are necessary elements of a power distribution system, as they provide a variety of control and protection functions. The protective relays monitor the conditions in the power distribution system and operate circuit breakers in response to the detection of adverse conditions, thus protecting several segments and components of the power distribution system from damage. The previous protective relays were analog devices, which have been largely replaced by digital protective relays. Digital protective relays include digital processing circuits that can be programmed to provide a wider variety of control and protection functions than those available with analog relay devices. Digital protective relays commonly include relay processing circuits to perform various protective control functions. The relay processing circuits can be implemented through various configurations of input / output (I / O) circuits, current transformers, voltage transformers, etc. These configurations are generally fixed in the protective relay unit, making it relatively difficult and time consuming to repair or replace the relay processing circuits or portions thereof. US Pat. No. 4,742,428 to Conrad discloses a protective relay that includes an operating unit that can be removed from an insulative housing through an opening in the front of the housing. The possibility of removing circuits from the protective relay allows routine tests, maintenance and replacement of internal relay circuits with minimal discomfort of the power distribution system. However, Conrad's protective relay includes rather conventional relay circuits that are fixed in their location within the operating unit that can be removed. It would be desirable for a protective relay device to allow relatively easy replacement or repair of the relay processing circuits. BRIEF DESCRIPTION OF THE INVENTION The present invention solves the aforementioned problems, and achieves additional advantages, by providing a protective relay device in which the relay processing circuits are implanted in the form of removable and replaceable modules, each of which performs a specified function. Each module includes a main control board that has basic circuits required for all the intended functions of the module, and also includes removable and replaceable submodules that include specialized circuits to perform specific functions. The modules may include a power supply module, a central processing unit module, and at least one digital signal processing module. The submodules can include input / output cards and voltage or current transformer cards. In accordance with the exemplary embodiments described below, the present invention allows changing the functions of a protective relay by replacing one or more modules or one or more submodules. BRIEF DESCRIPTION OF THE INVENTION The invention can be understood more fully by reading the following Detailed Description in conjunction with the accompanying drawings, in which like elements are designated by reference indicators, and in which : Figure 1 shows a protective relay device incorporating the modular / submodular structure contemplated by the present invention; Figure 2 is a module removed from the protective relay device of Figure 1; and Figures 3a-b, show a partial sectional view and a cross-sectional view, respectively, of the module of Figure 2. DETAILED DESCRIPTION With reference now to Figure 1, a protective relay device incorporating modules is shown. The protective relay device 10 is shown having an articulated panel that provides access to protective relay circuits, such as the panel described in the co-pending application, assigned to the same assignee herein entitled "Modular Control Panel for a Protective Relay. ", filed on the same date as the present, whose totality is incorporated by reference in this application. The internal protective relay circuits of the protective relay device 10 are provided in the form of modules 12. Each module performs a specified function or a series of functions relating to the protection and control of an electric power distribution system (not shown) operated by the protective relay device. Exemplary modules may include a power supply module, a current transformer module, a central processing unit (CPU) module, a digital signal processor (DSP) module, etc. Each module 12 can be removed and replaced separately (for example, slidably engaging or uncoupling slots or guides in the protective relay housing), allowing the protective relay device 10 to be updated or easily repaired by simple removal and replacement of one or more modules. Referring now to Figure 2, an individual module 12 is shown. The module is provided with contacts 14 at one end for electrically connecting the module to the power distribution system. At the opposite end, the module 12 is provided with connections (not shown) for communicating with a user's interface (e.g., the panel of the protective relay device 10). The contacts 14 are preferably connected to the power distribution system via a terminal block, which may be a conventional terminal block or a modular terminal block such as the one described in the co-pending application, assigned to the same assignee as this. entitled "Terminal Block for a Protective Relay", filed on the same date as the present one, whose totality is incorporated by reference in this application. Referring now to Figures 3a-b, a partial view is shown in a separate section and a cross-sectional view, respectively, of the module 12. As can be seen in Figure 3a, the module 12 is comprised of a main control board 16 and a plurality of submodule cards 18. In Figure 3a, the submodule cards are shown including input / output cards, but the submodule cards can alternatively be voltage transformer cards, current transformer cards, or any other type of card to allow the module 12 to perform its designated function or functions. Preferably, the main control board 16 contains circuits common to all the intended module functions, and is fixed in the housing of the module 20. The submodule cards 18 include specialized circuits so that the module is capable of performing specific intended module functions (for example, transformer cards that have specific voltage values or to allow the module to perform specific types of input / output operations). The submodule cards 18 can be removed and replaced separately from the main control board 16 and a housing of the module 20. The contacts 14 are designed to couple with a male end block, and are preferably welded on the submodule cards 18 As shown in Figure 3b, the submodule cards 18 are mechanically connected to the housing 20 along one side, and are electrically and mechanically connected to the main control board 16 along the opposite side. Preferably, the submodule cards 18 can be slidably cod with the main control board 16 to establish a suitable mechanical and electrical connection. As there are many different types of suitable connections, none will be specifically discussed here. A module in accordance with the present invention comprises a female terminal block that cos with a male terminal block as shown and described in the copending application, assigned to the same assignee of the present one entitled "Terminal Block for a Protective Relay". Preferably, the housing 20 should be formed such that a module in accordance with the present invention conveniently accepts this male end block in any configuration, regardless of whether the male end block includes short circuit appendages. To achieve this, and avoid short circuit when the module is cod with a male end block having short circuit appendages, the female block housing / module 20 is provided with extensions (not shown) of a suitable length which are placed to break the short appendage contact after the electrical contact is established between the contacts of the male terminal block and the female / module terminal block. The contacts of the female terminal block / module are preferably designed to withstand a current of approximately 500 amps for about one second, to be operable in an energy distribution system. An assembled module having sub-modules in accordance with the present invention can be easily inserted into a protective relay and secured using Tinnerman clips or other suitable fastening means. As exemplified by the embodiments described above, a modular / submodular protective relay in accordance with the present invention can provide numerous advantages over protective relay devices. For example, the protective relay can easily have modules removed and replaced in the field to allow improving or changing the functions of the protective relay, or to allow easy repairs.

Additionally, since the modules may be provided with submodules as described above, an individual module may have submodules removed and replaced in the field to allow for improving or changing the functions of the protective relay, or to allow for easy repairs. These aspects of the present invention provide significant advantages over conventional protective relays having fixed configurations of digital input and output circuits and / or fixed combinations of voltage and current transformers. Although the foregoing description includes many details and specifications, it should be understood that these are for illustrative purposes only and are not limitations of the invention. Many modifications of the modalities described above can be easily achieved without departing from the spirit and scope of the invention, as defined in the following claims and their legal equivalents.

Claims (18)

1. CLAIMS 1. A protective relay, comprising: a relay housing; and a backplane capable of mechanical and electrical connection to a plurality of removable and replaceable modules independently, including a power supply module, a central processing unit module, and at least one DSP module to provide protective control of an electrical power distribution system, wherein each module includes a module housing and a plurality of removable and replaceable submodules separately, so that the functions of a module can be changed by replacing one or more of the sub-modules.
2. 2. The protective relay of claim 1, wherein one or more of the submodules includes at least one contact for connection to an electrical distribution system.
3. 3. The protective relay of claim 2, wherein the at least one contact can withstand a current of about 500 amps for about one second.
4. 4. The protective relay of claim 2, wherein the modules can be connected to a terminal block regardless of whether the terminal block includes short circuit appendages.
5. The protective relay of claim 4, wherein the modules separate the short circuit appendages only after electrical contact between the terminal block and the at least one contact.
6. 6. The protective relay of claim 1, wherein the submodules are input / output submodules.
7. 7. The protective relay of claim 1, wherein the submodules are submodules of current transformer.
8. 8. The protective relay of claim 1, wherein the submodules are voltage transformer submodules.
9. 9. The protective relay of claim 1, wherein the modules are mounted to the relay housing using tinnerman clips.
10. 10. A module for performing a series of one or more functions in a protective relay, comprising: a module housing; a main control board in the housing; and a plurality of submodules removably inserted in the housing, each submodule performs portions of the functions of the module and is capable of communication with other sub-modules via the main control board, where the module can be removably inserted in a housing of relay of a protective relay.
11. The module of claim 10, wherein one or more of the plurality of submodules includes at least one contact for connection to an electrical distribution system.
12. The module of claim 10, wherein the at least one contact can withstand a current of about 500 amps for about one second.
13. The module of claim 10, wherein the module, when inserted into the relay housing, engages a terminal block regardless of whether the terminal block includes short circuit appendages.
14. The module of claim 13, wherein the module separates the short circuit appendages only after electrical contact between the terminal block and the at least one contact.
15. The module of claim 10, wherein the submodules are input / output submodules.
16. 16. The module of claim 10, wherein the submodules are submodules of current transformer.
17. The module of claim 10, wherein the submodules are voltage transformer submodules.
18. 18. The module of claim 10, wherein the submodules are submodules of current transformer.