WO2021053437A1

WO2021053437A1 - Control cubicle for protecting power equipment, and methods thereof

Info

Publication number: WO2021053437A1
Application number: PCT/IB2020/057915
Authority: WO
Inventors: V Balaji
Original assignee: General Electric Technology Gmbh
Priority date: 2019-09-16
Filing date: 2020-08-25
Publication date: 2021-03-25

Abstract

Embodiments of the present disclosure relate to a control cubicle (101) in a substation. The power equipment protection system (100) comprises a controller (201) configured to operate the circuit breaker (102) and monitor insulating fluid in the circuit breaker (102). The controller (201) generates a first signal (205) indicative of an operating condition of the controller (201) and a second signal (206) indicative of a level of the insulating fluid. The power equipment protection system (100) further comprises a logic block (202) configured to compare the first signal (205) with a power signal (209) received from a client server (103) to determine the operating condition of the controller (201) as one of healthy condition or an unhealthy conditi on and generate a third signal (207) when the operating condition is unhealthy condition, where the third signal (207) is provided to the client server (103) for scheduling maintenance activity.

Description

CONTROL CUBICLE FOR PROTECTING POWER EQUIPMENT, AND

METHODS THEREOF TECHNICAL FIELD

[001] The present disclosure relates in general to electrical power systems for substations of a power plant, and more specifically, but not exclusively to, a power equipment protection system a method of protecting power equipment in the substation and a method for monitoring and predicting insulation fluid level.

BACKGROUND

[002] A substation (generation or transmission or distribution or the like) are operated at high voltages (above 75kV). Power equipment like transformers, generators, and other relaying, measuring and control equipment are often prone to damages due to faults in transmission lines. Generally, circuit breakers are installed to isolate a faulty line from damaging the power equipment. In atypical substation, control cubicles (also referred as sentinels or control cabinet or marshalling box) are placed to operate circuit breakers. The control cubicles regularly monitor line parameters and conditions of site to detect faults. It is critical for the control cubicle to operate the circuit breakers without delay. Circuit breakers are constantly monitored and maintenance is scheduled to ensure seamless protection for the power equipment. Maintenance of circuit breakers includes detecting insulating fluid such as Sulphur Hexafluoride (SF6) or fluid (dielectric medium) used to extinguish arcs in the circuit breakers. The insulating fluid is filled in a circuit breaker tank and must be regularly re-filled to maintain sufficient pressure to extinguish an arc generated between terminals of the circuit breaker when the circuit breaker is opened.

[003] A drawback in the existing control cubicles is that the circuit breakers cannot be operated when a fault resides in the control cubicle. Further, control cubicles are not regularly checked for faults and improper maintenance of the control cubicle increases the risk of operational faults.

[004] Another drawback in the existing systems is to accurately scheduling refilling of the insulating fluid in the circuit breaker tank and to maintain the required pressure of the insulating fluid. [005] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY

[006] In some embodiments, a control cubicle for a substation of a power plant is disclosed. The control cubicle comprises a controller configured to operate a circuit breaker in the substation. The controller is further configured to monitor insulating fluid in the circuit breaker. The controller generates a first signal indicative of an operating condition of the controller and generates a second signal indicative of a level of the insulating fluid. The control cubicle further comprises a logic block configured to compare the first signal with a power signal received from a client server to determine the operating condition of the controller as one of healthy condition or an unhealthy condition. The logic block is further configured to generate a third signal when the operating condition of the controller is unhealthy condition. The third signal is provided to the client server for scheduling maintenance activity.

[007] In some embodiments, a method for protecting power equipment in a substation of a power plant is disclosed. A control cubicle is configured to operate a circuit breaker in the substation. The method comprises comparing a power signal obtained from a client server and a first signal obtained from a controller of the control cubicle. The first signal is indicative of an operating condition of the controller. The method further comprises identifying one of a healthy and an unhealthy condition of the controller based on the comparison. Thereafter, the method comprises generating at least a third signal and a priority trip signal when the controller is operating in the unhealthy condition. The third signal is provided to the client server for scheduling maintenance activity and the priority trip signal is used for tripping the circuit breaker.

[008] In some embodiments, a method for monitoring and predicting level of insulating fluid stored in a circuit breaker in a substation of a power plant is disclosed. The method comprises obtaining previously filled insulated fluid data, a rate of leakage of the insulating fluid and historical prediction data. The insulating fluid is stored in a tank associated with the circuit breaker. The method further comprises predicting a first timestamp for subsequent refilling of the insulating fluid based on the rate of leakage of the insulating fluid, the historical data of insulating fluid, and the previously filled insulating fluid data. The first timestamp is provided to the chent server for scheduling maintenance activity.

[009] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS [0010] The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

[0011] Fig. 1 is a simplified illustration of a substation for protecting power equipment in the substation, in accordance with some embodiments of the present disclosure;

[0012] Fig. 2 is an exemplary illustration of a power equipment protection system for scheduling maintenance activity in a substation, in accordance with some embodiments of the present disclosure;

[0013] Fig. 3 is an exemplified flow chart illustrating steps for protecting power equipment in a substation, in accordance with some embodiments of the present disclosure;

[0014] Fig. 4 is an exemplified flow chart illustrating steps for monitoring and predicting level of insulating fluid in the circuit breaker, in accordance with some embodiments of the present disclosure; and

[0015] Fig. 5 is an exemplary control cubicle having communication modules isolated from control modules, in accordance with some embodiments of the present disclosure.

[0016] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown. DETAILED DESCRIPTION

[0017] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0018] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0019] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus. [0020] Embodiments of the present disclosure relate to a control cubicle in a substation of a power plant, a method for protecting power equipment in a substation of a power plant and a method for monitoring and predicting insulation fluid in a circuit breaker of a substation.

[0021] Fig. 1 is a simplified illustration of a substation of a power plant. The substation may be a part of a power generation plant or a transmitting plant or a distribution plant. In some embodiments the substation is operated at high voltage, e.g., 72kV, 145kV, 245kV, 400kV, 800kV, 1200k V, 1500kV. The substation comprises a plurality of power equipment such as power transformers, power generators. The substation also comprises feeder busses, transmission lines, control equipment and monitoring equipment. Fig. 1 shows a power equipment protection system (100), a control cubicle (101), a circuit breaker (102), a client server (103) and a transmission line (104). The control cubicle (101) and the circuit breaker (102) may form a part of the power equipment protection system (100). The power equipment protection system (100) may be a centralized system such as a Distributed Control System (DCS) or a Supervisory Control And Data Acquisition (SCADA) system. The power equipment protection system (100) may comprises a central server (not shown) to receive various parameters of the substation, such as line parameters and power equipment parameters to monitor and perform analysis on the various parameters. The analysis may be performed to detect faults in the substation and take appropriate measures. In some embodiments, the substation may comprise a plurality of control circuit breakers (not shown) and a plurality of control cubicle (not shown). Fig. 1 shows one circuit breaker (102) and one control cubicle (101) only for illustration and a person skilled in the art should not consider this as a limitation. In one embodiment, a single control cubicle (e.g., 101) may operate a plurality of circuit breakers (102). Fig. 1 shows the circuit breaker connected to a transmission line (104). In an exemplary embodiment the circuit breaker (102) may be connected to a feeder bus or a transformer or any power equipment or terminals for isolating a faulty circuit from rest of the power equipment, modules and circuits of the substation.

[0022] In some embodiments, the control cubicle (101) is configured to operate the circuit breaker (102). In some embodiments, the control cubicle (101) may further be configured to obtain a plurality of parameters of the transmission line (104) to detect fault in the transmission line ( 104) and operate the circuit breaker ( 102) accordingly. In some embodiments, if the circuit breaker (102) is connected to a transformer, the control cubicle (101) is configured to receive a plurality of parameters of the transformer and operate the circuit breaker (102) when a fault is detected in the transformer. The circuit breaker (102) may be connected to high voltage terminals or equipment such as a high voltage transmission lines, high voltage feeder busses, high voltage transformers, and the like. In some embodiments, the control cubicle (101) may communicate with the central server via an 1EC 61850 station bus. In some embodiment, the control cubicle (101) may be controlled remotely by an operator in a control room. In some embodiment, the control cubicle (101) may comprise a Human Machine Interface (HMI).

[0023] In some embodiments, the client server (103) is a control room electrically and communicatively connected to the control cubicle (101). The client server (103) may be used to monitor status of the substation regulariy . In some embodiments, the client server (103) may be connected to a HMI for interacting with the operator.

[0024] Fig. 2 is an exemplary illustration of a power equipment protection system (100) for scheduling maintenance activity in a substation. The control cubicle (101) of the power equipment protection system (100) comprises a controller (201) and a logic block (202). A first relay is configured between the client server (103) and the controller (201). A second relay (204) is configured between the controller (201) and the logic block (202). The client server (103) is configured to provide a power signal (209) to the controller (201) and the logic block (202). In some embodiments, the power signal (209) may indicate that a scheduled maintenance activity is required in the substation, and the circuit breaker (102) needs to be tripped to isolate the power equipment from the transmission lines (104).

[0025] In some embodiments, the controller (201) is configured to operate the circuit breaker (102). The controller (201) generates a first signal (205) indicative of an operating condition of the controller (201). The operating condition is one of a healthy condition and an unhealthy condition. The first signal (205) may be a voltage signal or a current signal, for example a current value of 1 A or 05 A or 5 A. In some embodiments, amplitude values of the current signal or the voltage signal may indicate the operating condition of the controller (201). In some embodiments, frequency values of the current signal or the voltage signal may indicate the operating condition of the controller (201). For example, when the first signal (205) has unexpected current values, the controller (201) may be determined to be unhealthy. In some embodiments, the controller (201) trips the circuit breaker (102) while operating in the healthy condition. In some embodiments, the controller (201) fails to trip the circuit breaker ( 102) while operating in the unhealthy condition. In some embodiments, the controller (201 ) is configured to trip the circuit breaker (102) when a fault is detected in the transmission line (104). The controller (201) may trip the circuit breaker (102) upon receiving the power signal from the client server (103). The power signal (209) may be a voltage or current signal. For example, the power signal (209) may be a 5V signal. In some embodiments, the first signal (205) and the power signal (209) are same signals. For example, when the client server (103) provides the power signal (209), the controller (201) generates the first signal (205) having same electrical characteristics of the power signal (209). In some embodiments, the controller (201) is configured to monitor at least one of, a secondary contact (auxiliary contacts) of the circuit breaker (102), operating mechanism readiness of the circuit breaker (102), pole discrepancy of the circuit breaker (102), anti-pumping (i.e.) avoiding repeated closing of the circuit breaker

(102), the insulating fluid in the circuit breaker (102). The insulating fluid is filled in a tank associated with the circuit breaker (102). In exemplary embodiments, the insulating fluid is maintained at a pressure ranging from 2 bar to 10 bar. In an example , the insulation fluid is maintained at 7 bar in an 800kV circuit breaker (102).

[0026] In some embodiments, the controller (201) monitors the insulating fluid and predicts a date and time for subsequent filling of the insulating fluid based on data comprising at least a rate of leakage of the insulating fluid, a previously filled date and historical data of insulating fluid filing. The controller (201) generates the second signal (206) when the insulating fluid is determined to be less than a second threshold value. For example, the second signal is generated when the pressure of the insulating fluid drops below a threshold value of 6.4 bar. In some embodiments, there can be a plurality of second threshold values. For instance, the a threshold value of 6.1 bar may set for locking out the circuit breaker (102), and when the insulating fluid drops below the threshold value of 6.1 bar, the circuit breaker (102) is locked out until the circuit breaker (102) is attended by maintenance operator. A threshold value of 6.4 may be set for generating an alarm, and when the insulating fluid drops below the threshold value of 6.4 bar an alarm is generated indicating low level of the insulating fluid.

[0027] In some embodiments, the logic block (202) is configured to compare the first signal (205) generated by the controller (201) with the power signal (209) received from the client server (103) to determine the operating condition of the controller (201) as one of healthy condition or unhealthy condition. The controller (201) may provide the first signal (205) at regular time intervals to the logic block (202). In a further embodiment, the logic block (202) may compare the first signal (205) with expected signals to determine operating condition of the controller (201) when the client server (103) does not provide the power signal (209) (i.e., when scheduled maintenance activity is not planned). For example, the controller (201) may regularly provide a 5V signal to the logic block (202) during healthy condition. When the controller (201) provides a 5.5V signal, the logic block (202) may generate a third signal (207) indicating that the controller (201) is unhealthy. In an embodiment, the logic block (202) may not generate the third signal (207) upon determining that the controller (201) is operating in the healthy condition. A person of ordinary skill will appreciate that the said voltage values are example for illustrating a scenario. The above example should not be considered as a limitation. [0028] In some embodiments, the logic block (202) receives the power signal (209) from the client server (103). The client server ( 103) may provide the power signal (209) to the controller (201) and the logic block (202) simultaneously. As previously mentioned, the power signal (209) and the first signal (205) may have same electrical characteristics. When the client server (103) provides the power signal (209) to the controller (201) and the logic block (202), the logic block (202) compares the power signal (209) with the first signal (205). When the logic block (202) determines that the first signal (205) deviates from the power signal (209) by a first threshold value, For example, if the power signal (209) is a 5 V signal and the first signal (205) deviate by 0.5V, then the logic block (202) generates the third signal (207) indicating that the controller (201) is unhealthy. The third signal (207) is provided to the client server (103) for scheduling maintenance activity.

[0029] In some embodiments, the logic block (202) is configured to generate a priority trip signal (210) upon determining the controller (201) is unhealthy. The logic block (202) generates the priority trip signal (210) when the controller (201) sends out a signal which is other than indication of healthy signal. The priority trip signal (210) trips the circuit breaker (102). The priority trip signal (210) and the third signal (207) may be generated simultaneously. The logic block (202) may restore the circuit breaker (102) after the controller (201) is rectified. For example, the controller (201) may regularly provide a 5V signal to the logic block (202) during healthy condition. When the controller (201) provides a 5.5V signal or IV or 0V, the logic block (202) may generate a third signal (207) indicating that the controller (201) is unhealthy. A voltage of 5.2V may still be consider as healthy condition.

[0030] The logic block (202) may be a Programmable Logic Circuit (PLC) or a processor or a controller or an embedded system or any other logic circuit or computing unit which is capable of performing the tasks of the logic block (202).

[0031] A maintenance operator may perform a maintenance activity to service or rectify faults in the controller (201). The control cubicle (101) comprises a first side and a second side. In some embodiments, the first and second side may be rear side and front side or vice versa. The first side encloses a plurality of control peripherals and a second side encloses a plurality of communication peripherals. The control peripherals are not accessed during maintenance in the communication peripherals and vice versa. The control peripherals are grouped together and the communication peripherals are grouped together such that the maintenance operator may access only the control peripherals configured on either of the first side or the second side when maintenance is required in the control peripherals. Likewise, maintenance operator may access only the communication peripherals configured in the other side when the maintenance is required in the communication peripherals without disturbing the control peripherals. Fig. 5 shows an exemplary diagram of the control cubicle (101) \showing the first side (501) and the second side (502). In some embodiments, when the firmware/ software has to be updated in the control cubicle (101), the operator may connect to the control cubicle (101) via one or more communication ports (not shown) provided in the control cubicle (101). For example, the communication port may be an Ethernet port, which enables a computer to be connected via an Ethernet cable. In some embodiments, the control cubicle (101) may have a wireless module to provide remote access. For example, the operator may update the firmware of the control modules or the communication modules remotely via the wireless module . The communication module may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10/100/1000 Base T), transmission control protocol/Intemet protocol (TCP/IP), token ring, IEEE 802.1 la/b/g/n/x, etc. The communication network may include, without limitation, a direct interconnection, wired connection, e-commerce network, a peer to peer (P2P) network. Local Area Network (LAN), Wide Area Network (WAN), wireless network (e.g., using Wireless Application Protocol (WAP)), the Internet, Wireless Fidelity (Wi-Fi), etc. In an embodiment, the isolation of the communication modules from the control modules decreases the impact of Electro-Static Discharges (ESD) on the control modules. The ESD may occur due to the communication modules.

[0032] Fig. 3 and Fig. 4 show a flow chart. As illustrated in Fig. 3 and Fig. 4, the methods 300 and 400 may comprise one or more steps. The methods 300 and 400 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform particular functions or implement particular abstract datatypes.

[0033] The order in which the methods 300 and 400 are described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.

[0034] Step (301) comprises comparing the power signal (209) obtained from the client server (103) with the first signal (205) received from the controller (201). The comparison is made to determine operating condition of the controller (201) as one of healthy or unhealthy. In some embodiments, the first signal (205) indicates the operating condition of the controller (201).

[0035] Step (302) comprises identifying one of the healthy condition or the unhealthy condition of the controller (201) based on the comparison. The comparison is made between a value associated with the power signal (209) and a value associated with the first signal (205). The values may be a current amplitude or voltage amplitude in some embodiments. The unhealthy condition of the controller (201) is identified when the value of the first signal (205) deviates from the value of the power signal (209) by the first threshold value. In one embodiment the unhealthy condition of the controller (201) is identified when the value of the first signal (205) deviates from a predefined fixed value range.

[0036] Step (303) comprises generating at least the third signal (207) and the priority trip signal (210) when the controller (201) is operating in the unhealthy condition. Once the first signal (205) is determined to deviate from the power signal (209) by the first threshold value, at least one of the third signal (207) and the priority trip signal (210) is generated. In some embodiments, the third signal (207) and the priority trip signal (210) are generated simultaneously. The third signal (207) is provided to the client server (103) indicating that the controller (201) is faulty/ unhealthy and maintenance is required. The priority trip signal (210) trips the circuit breaker (102) on behalf of the controller (201). In some embodiments, the circuit breaker ( 102) is reclosed / restored after the fault / unhealthy condition in the controller

(201) is rectified. The circuit breaker (102) may be restored using auto-reclosing mechanisms.

[0037] The insulating fluid is generally stored to extinguish an arc generated in the circuit breaker (102). A commonly used insulating fluid is the SF6 gas. In some embodiments other insulating fluids such as dielectric medium (e.g., a gas of certain dielectric coefficient) may be used to extinguish the arc in the circuit breaker (102). Following description is written specific to the SF6 gas. However, this should not be construed as a limitation and the following description is equally applicable to commonly used other insulating fluids in the circuit breaker (102). It is essential to maintain the SF6 gas at specific pressure (normally around 2 bar to 10 bar). For example, the SF6 is maintained at 7 bar for a particular make and type of the circuit breaker (102). Conventional systems make use of a plurality of sensors to detect the level of SF6 in the circuit breaker (102) and generate an alarm when the level of SF6 drops below a threshold value. The following description describes the method (400) for monitoring and predicting insulation fluid in the circuit breaker (102).

[0038] Step (401) comprises obtaining previously filled insulting fluid data. In some embodiments, the controller (201) may store the previously filled insulating data. In some embodiments, the DCS or the SCADA system may store data related to filling of SF6 gas into the tank of the circuit breaker (102). In some embodiments, the operator may enter into the DCS or SCADA system, each time when the circuit breaker (102) is filled with SF6 gas. The operator may also enter details such as pressure before filling the SF6 gas, pressure after filling the SF6 gas, temperature of the SF6 gas, date and time of filling the SF6 gas, a rate of leakage of the SF6, historical prediction data and amount of SF6 gas filled. In some embodiments, the rate of leakage of the SF6 is the leakage of the SF6 daily or monthly or yearly. In some embodiments, the rate of leakage may be represented as decrease in pressure of the SF6 gas. For example, the rate of leakage may be 0.035 bar per annum. That is, the pressure of the SF6 gas decrease by 0.035 bar annually. In an embodiment the rate of leakage data may be used to predicting subsequent filing for the SF6 gas. In some embodiments, the historical prediction data comprises previously predicted date and time for filling the SF6 gas in the circuit breaker (102). The historical prediction data is used for analysing the annual rate of filling the SF6 gas. Also, the historical prediction data is used for predicting subsequent filling of the SF6 gas.

[0039] Step (402) comprises predicting a first date and time for subsequent refilling of the insulating fluid based on the rate of leakage of the insulating fluid, the historical prediction data and the previously filled insulating fluid data. Table 1 shows an example of predicting the subsequent filling of the SF6 gas.

Table 1

[0040] The Table 1 shows the details for a 800kV circuit breaker (102). The first column of the Table 1 shows that the weight of the SF6 gas in the circuit breaker (102) is 87 kg, the pressure of the SF6 gas after re-fill is 7 bar, the second threshold value to attain lockout state is 6.1 bar, the second threshold value to generate alarm is 6.4 bar, the leakage rate per annum is 0.035 bar, the leakage rate per day is 9.589E-05 bar, difference pressure to obtain alarm is 0.6 bar, number of days to reach alarm with the current leakage rate is 6257 days. The above details may be obtained from the DCS or the SCADA system based on historical SF6 filling data and historical prediction data. Also, the above date may be generic data based on type and make of the circuit breaker (102). For example, the above data may be defined for a “X” type of circuit breaker ( 102) manufactured by “Y” company. Thus, the above data may be common to all the circuit breakers (102) of type “X’' and manufactured by "Y”. The above data may be obtained from a specification associated with the circuit breaker (102) of type “X” and manufactured by ‘Ύ”. The following details are the previously filled data comprising last refilled on 09-12-2017, last alarm attained on 28-09-2018. Further, the following data is specific to the specific circuit breaker (102) and may be captured by the controller (201).

[0041] As per the details in the table 1, the circuit breaker (102) oftype“X” and manufactured by “Y” is supposed to generate the alarm after 6257 days as per the leak rate of 0.035 bar per annum. According to the previous refilled data, the time to attain alarm stage is 293 days. The value of 293 days is calculated based on the last refill date and the last alarm attained date. Using these two parameters, it is estimated that the rate of leakage of the SF6 gas is increased, therefore the SF6 gas is to be refilled in the next 293 days. Thus, the next refill date is predicted to be 08-10-2018 and the next date of generating and alarm is predicted to be 26-07-2019. The circuit breaker (102) may be programmed to provide intimation before generating the alarm. For example, the circuit breaker (102) may be programmed to intimate two weeks prior (12- 07-2019) to generating the alarm. In some embodiments, an intimation regarding the refill and an intimation or the second signal (206) is provided to the client server (103). Furthermore, if the maintenance is not performed, the circuit breaker ( 102) is locked out until the maintenance is performed. Therefore, the method (400) provides safety and enables timely maintenance activity is planned to increase life of the circuit breaker (102). The predicted data is stored in the DCS and the SCADA system for using in subsequent prediction of the date and time. In some embodiments, the first date and time is the date and time for re-filling the SF6 gas. In some embodiments, a second date and time is the date and time for at least generating the alarm and locking out the circuit breaker (102). The controller (201) predicts a second date and time based on the first date and time and a threshold value where the threshold value results in the second date and time being less than the first date and time. In some embodiments, the second signal (206) is generated based on the predicted second date and time. Thus, accurately predicting the refill of the SF6 in the circuit breaker (102) enables maintaining the required pressure in the circuit breaker (102). The accurate pressure in the circuit breaker (102) ensures proper tripping of faulty circuit and extinguishes arcs completely.

[0042] In some embodiments, tire present disclosure detects the unhealthy condition of the controller (201) early and intimates the client server (103) for scheduling maintenance activity.

Hence, faults in the controller (201) is reduced and life of the controller (201) is increased.

[0043] In some embodiments, the plurality of equipment in the substation is protected even when the controller (201) is unhealthy or faulty.

[0044] In some embodiments, the SF6 refilling date and time is accurately predicted, thereby securing the substation by completely extinguishing the arcs in the circuit breaker (102).

[0045] The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", and "one embodiment" mean "one or more (but not all) embodiments of the invention(s)" unless expressly specified otherwise. [0046] The terms "including", "comprising", "having” and variations thereof mean "including but not limited to", unless expressly specified otherwise.

[0047] The enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.

[0048] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

[0049] When a single device or article is described herein, it will be readily apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device/article may be used in place of the more than one device or article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features . Thus, other embodiments of the invention need not include the device itself.

[0050] The illustrated operations of Fig. 3 and Fig. 4 show certain events occurring in a certain order. In alternative embodiments, certain operations may be performed in a different order, modified or removed. Moreover, steps may be added to the above described logic and still conform to the described embodiments. Further, operations described herein may occur sequentially or certain operations may be processed in parallel. Yet further, operations may be performed by a single processing unit or by distributed processing units.

[0051] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the fallowing claims. [0052] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

REFERRAL NUMERALS:

Power equipment protection system (100) Control cubicle (101)

Circuit breaker (102) Client server (103)

Transmission lines (104)

Controller (201)

Logic block (202)

First relay (203) Second relay (204)

First signal (205)

Second signal (206)

Third signal (207)

Trip signal (208) Power signal (209)

Priority trip signal (210)

First side (501)

Second side (502)

Claims

We claim:

1. A control cubicle (101) for a substation of a power plant, comprising: a controller (201) configured to operate a circuit breaker (102) in the substation and monitor insulating fluid in the circuit breaker (102), wherein the controller (201) generates a first signal (205) indicative of an operating condition of the controller (201) and a second signal

(206) indicative of a level of the insulating fluid; and a logic block (202) configured to: compare the first signal (205) generated by the controller (201) with a power signal (209) received from a client server (103) to determine the operating condition of the controller (201) as one of healthy condition or an unhealthy condition; and generate a third signal (207) when the operating condition is unhealthy condition, wherein the third signal (207) is provided to the client server (103) for scheduling maintenance activity.

2. The control cubicle (101) as claimed in claim 1, wherein the controller (201) trips the circuit breaker (102) while operating in the healthy condition.

3. The control cubicle (101) as claimed in claim 1, wherein the controller (201) fails to trip the circuit breaker (102) while operating in the unhealthy condition.

4. The control cubicle (101) as claimed in claim 1, wherein the logic block (202) is configured to determine the unhealthy operating condition of the controller (201) when a value of the first signal (205) deviates from a value of the power signal (209) by a first threshold value.

5. The control cubicle (101) as claimed in claim 1, wherein the logic block (202) is configured to generate a priority trip signal (210) to trip the circuit breaker (102) upon determining the unhealthy condition of the controller (201). 6. The control cubicle (101) as claimed in claim 5, wherein one of the logic block (202) and the controller (201) is configured to restore the circuit breaker (102) after the controller (201) is rectified from unhealthy condition.

7. The control cubicle (101) as claimed in claim 1, comprises a first relay (203) configured between the client server (103) and the logic block (202) and a second relay (204) configured between the controller (201) and the logic block (202).

8. The control cubicle (101) as claimed in claim 1, wherein the controller (201) monitors the insulating fluid and predicts a date and time for subsequent filling of the insulating fluid based on data comprising at least a rate of leakage of the insulating fluid, a previously filled date and historical data of insulating fluid filing, wherein the controller (201) generates the second signal (206) when the insulating fluid is determined to be less than a second threshold value. 9. The control cubicle (101) as claimed in claim 1 comprising a first side and a second side, wherein the first side encloses a plurality of control peripherals and a second side encloses a plurality of communication peripherals, wherein the control peripherals are not accessed during maintenance in the communication peripherals and vice versa. 10. A method of protecting power equipment in a substation of a power plant, by a control cubicle (101) configured to operate a circuit breaker (102) in the substation, the method comprising: comparing a power signal (209) obtained from a client server (103) and a first signal (205) obtained from a controller (201) of the control cubicle (101), wherein the first signal (205) is indicative of an operating condition of the controller (201); identifying one of a healthy and an unhealthy condition of the controller (201) based on the comparison; and generating at least a third signal (207) and a priority trip signal (210) when the controller (201) is operating in the unhealthy condition, wherein the third signal (207) is provided to the client server ( 103) for scheduling a maintenance activity for the controller (201 ) and the priority trip signal (210) is used to trip the circuit breaker (102).

11. The method as claimed in claim 10, wherein the unhealthy condition is identified when a value of the first signal (205) deviates from a value of the power signal (209) by a first threshold value.

12. The method as claimed in claim 10, wherein the circuit breaker (102) is restore after the controller (201) is rectified from the unhealthy condition.

13. A method for monitoring and predicting level of insulating fluid stored in a circuit breaker in a substation of a power plant, the method comprising: obtaining previously filled insulating fluid data, a rate of leakage of the insulating fluid and historical prediction data, wherein the insulating fluid is stored in a tank of with a circuit breaker (102); and predicting a first date and time for subsequent refilling of the insulating fluid based on the rate of leakage of the insulating fluid, the historical prediction data and the previously filled insulating fluid data, wherein the first date and time is provided to the client server (103) for scheduling maintenance activity . 14. The method as claimed in claim 13, wherein the previously filled insulating fluid data comprises at least a date and time of filling the insulating fluid in the tank.

15. The method as claimed in claim 13, comprises predicting a second date and time based on the first date and time and a threshold value wherein the threshold value results in second date and time being less than the first date and time.

16. The method as claimed in claim 15, wherein a second signal (206) is generated based on the predicted second date and time, wherein the second signal (206) is provided to the client server (103) for scheduling maintenance activity.