WO2019166535A1

WO2019166535A1 - A relay protection apparatus and method, and a computer storage medium

Info

Publication number: WO2019166535A1
Application number: PCT/EP2019/054950
Authority: WO
Inventors: Shou Ming LI; Fei Wang; Yong Hou; Wei Wei Liu
Original assignee: Siemens Aktiengesellschaft
Priority date: 2018-02-28
Filing date: 2019-02-28
Publication date: 2019-09-06
Also published as: CN110212494A

Abstract

The present invention provides a relay protection apparatus (10) and method (601, 602, 603), and a computer storage medium. The method comprises: acquiring an output alternating voltage, an output alternating current, an input direct voltage and an input direct current of a direct/alternating current system, acquiring an output alternating current active power and an input direct current power, determining, based on the output alternating current active power and the input direct current power, whether an internal consumption power of the direct/alternating current system exceeds a first threshold, and if yes, confirming that protection needs to be enabled for the direct/ alternating current system; or, acquiring an output direct voltage, an output direct current, an input alternating voltage and an input alternating current of an alternating/direct current system, acquiring an output direct current power and an input alternating current active power, determining, based on the output direct current power and the input alternating current active power, whether an internal consumption power of the alternating/direct current system exceeds a second threshold, and if yes, confirming that protection needs to be enabled for the alternating/direct current system. The present invention achieves system-level relay protection on the direct/ alternating current system or the alternating/direct current system.

Description

Specification

A Relay Protection Apparatus and Method, and a Computer Storage

Medium

Technical Field

The present invention relates to the technical field of power equipment protection, in particular to a relay protection apparatus and method, and a computer storage medium.

Background Art

Relay protection is an important measure to detect faults or abnormal conditions occurring in the power system, and then send out alarm signals or directly isolate and clear the part with faults .

At present, the relay protection used by power grids for generators, transformers, transmission lines, etc., provides protection on the alternating power grid. With a large amount of high-power direct current equipment used in the power grid, there are alternating/direct current or direct/alternating current converters, for example, in rail transit, photovoltaic, wind power and direct current charging equipment or the like that generally perform relay protection on the alternating and direct sides thereof, respectively, therefore, multiple items of equipment and components are required to complete the relay protection function of the equipment.

Description of the Invention

In order to solve the above problems, the present invention provides a relay protection apparatus to achieve system-level relay protection on the direct/alternating current system or the alternating/direct current system;

the present invention further provides a relay protection method to achieve system-level relay protection on the direct/alternating current system or the alternating/direct current system; and

the present invention further provides a computer storage medium to achieve system-level relay protection on the direct/alternating current system or the alternating/direct current system.

To achieve the above purposes, the present invention provides the following technical solutions:

a relay protection apparatus, comprising:

an alternating voltage acquirer, configured to acquire an alternating voltage of an alternating current end of a protected system and to output the alternating voltage to a first ADC; an alternating current acquirer, configured to acquire an alternating current of the alternating current end of the protected system and to output the alternating current to the first ADC;

a first ADC, configured to perform analog-to-digital conversion on received alternating voltage or alternating current and then send the converted alternating voltage or alternating current to a processor;

a direct voltage acquirer, configured to acquire a direct voltage of a direct current end of the protected system and to output the direct voltage to a second ADC;

a direct current acquirer, configured to acquire a direct current of the direct current end of the protected system and to output the direct current to the second ADC;

a second ADC, configured to perform analog-to-digital conversion on received direct voltage or direct current and then send the converted direct voltage or direct current to the processor; and

a processor, configured to acquire, based on the alternating voltage and the alternating current, an alternating current active power of the alternating current end, acquire, based on the direct voltage and the direct current, a direct current power of the direct current end, and determine, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirm that protection needs to be enabled for the protected system.

Through the above solution, the present invention achieves system-level relay protection on the direct/alternating current system or the alternating/direct current system.

According to the above relay protection apparatus, if an output end of the protected system is an alternating current end and an input end thereof is a direct current end, the action of the processor determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system, specifically comprises: determining whether an inequation \P_al-P_dll-(t-k!)P_dl > Pn is satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein, Pal IS the alternating current active power, P_dl is the direct current power, Jel is a set first power conversion efficiency factor, and P_ri is a preset first threshold;

alternatively, if an input end of the protected system is an alternating current end and an output end thereof is a direct current end, the action of the processor determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system, specifically comprises:

determining whether an inequation 1^₁₂ - -P_«2l - Cl - *2)^_e2 > P z i s satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein, P_a2 is the alternating current active power, P_d2 is the direct current power, k2 is a set second power conversion efficiency factor, and P_r2 is a second threshold . According to the above relay protection apparatus, if the alternating current end is three-phase alternating current,

the alternating voltage acquirer acquires an alternating voltage of the alternating current end of the protected system, specifically is: acquiring an alternating voltage of each phase of the alternating current end of the protected system;

the alternating current acquirer acquiring an alternating current of the alternating current end of the protected system, specifically is: acquiring an alternating current of each phase of the alternating current end of the protected system; and

the processor acquiring an alternating current active power of the alternating current end, is: acquiring, based on the alternating voltage of each phase of the protected system and the alternating current of each phase of the protected system, an alternating current active power of each phase, respectively, and summating the alternating current active powers of three phases to obtain the alternating current active power of the protected system.

Through the above solution, the present invention achieves system-level relay protection on the direct/alternating current system or the alternating/direct current system where the alternating end is three-phase alternating current.

According to the above relay protection apparatus, if the input end of the protected system is an alternating current end, and the output end thereof is a direct current end that is multi- path direct current,

the direct voltage acquiring acquires a direct voltage of the direct current end of the protected system, is: acquiring a direct voltage of each path of the direct current end of the protected system;

the direct current acquiring acquires a direct current of the direct current end of the protected system, is: acquiring a direct current of each path of the direct current end of the protected system; and

the processor acquiring an output direct current power of the direct current end, is: acquiring, based on the direct voltage of each path of the protected system and the direct current of each path of the protected system, a direct current power of each path, respectively, and summating the direct current powers of three paths to obtain the direct current power of the protected system.

Through the above solution, the present invention achieves system-level relay protection on the alternating/direct current system where the output direct current end is multi-path direct current .

According to the above relay protection apparatus, if the input end of the protected system is an alternating current end and the output end thereof is a direct current end, the apparatus will further comprise a BI device, configured to acquire an operating state of the protected system and to output the operating state to the processor, the operating state being any one of the following states: a normal working state, a starting state, and a closing state;

and the processor is further configured to:

determine, based on the operating state of the protected system sent by the BI device, a preset threshold corresponding to the operating state.

Through the above solution, the present invention achieves targeted system-level relay protection on the direct/alternating current system with nonlinear factors.

The protected system comprises at least one direct current apparatus and one alternating current apparatus.

A further aspect of the present invention provides a relay protection method, comprising:

acquiring an alternating voltage and an alternating current of an alternating current end of a protected system, and acquiring, based on the alternating voltage and the alternating current, an alternating current active power;

acquiring a direct voltage and a direct current of a direct current end of the protected system, and acquiring, based on the direct voltage and the direct current, a direct current power; and determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system exceeds a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system.

According to the above relay protection method, if an output end of the protected system is an alternating current end and an input end thereof is a direct current end, the step of determining whether an internal consumption power of the protected system exceeds a preset threshold, and if yes, confirming protection needs to be enabled for the protected system, specifically comprises:

determining whether an inequation \P_al - P_dl| - (1 - k)P_dl > P_T1 is satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein P_gl is an output alternating current active power, P_dl is an input direct current power, Jtl is a set first power conversion efficiency factor, and

P_T1 is a preset first threshold; alternatively, if an input end of the protected system is an alternating current end and an output end thereof is a direct current end, the step of determining whether an internal consumption power of the protected system exceeds a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system, specifically comprises:

determining whether an inequation \P_d2~P_a2\-i -k2)P_a2>P_T2 iS satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein P_d2 is an output direct current power, P_a2 is an input alternating current active power, k2 is a set second power conversion efficiency factor, and P_T2 is a preset second threshold.

According to the above relay protection method, if the alternating current end is three-phase alternating current,

the acquiring of an alternating voltage of the protected system is: acquiring an alternating voltage of each phase of the alternating current end of the protected system;

the acquiring of an alternating current of the protected system is: acquiring an alternating current of each phase of the alternating current end of the protected system; and

the acquiring of an alternating current active power of the alternating current end is: acquiring, based on the alternating voltage of each phase of the protected system and the alternating current of each phase of the protected system, an alternating current active power of each phase, respectively, and summating the alternating current active powers of three phases to obtain the alternating current active power of the protected system.

According to the above relay protection method, if the input end of the protected system is an alternating current end, and the output end thereof is a direct current end that is multi- path direct current,

the acquiring of a direct voltage of the direct current end of the protected system is: acquiring a direct voltage of each path of the direct current end of the protected system;

the acquiring of a direct current of the direct current end of the protected system is: acquiring a direct current of each path of the direct current end of the protected system; and

the acquiring of an output direct current power of the direct current end is: acquiring, based on the direct voltage of each path of the protected system and the direct current of each path of the protected system, a direct current power of each path, respectively, and summating the direct current powers of three paths to obtain the direct current power of the protected system.

According to the above relay protection method, the method thereof further comprises acquiring an operating state of the protected system; and

before determining whether an internal consumption power of the protected system exceeds a preset threshold, the method further comprises:

acquiring the operating state of the protected system, the operating state being any one of the following states: a normal working state, a starting state, and a closing state, and determining, based on the operating state, a preset threshold corresponding to the operating state.

A computer-readable storage medium, having a computer program stored thereon, wherein, when executed by a processor, the computer program implements the steps of the relay protection method according to any one of the above items.

A relay protection apparatus comprising: a processor and a memory,

the memory storing an application program executable by the processor and configured to cause the processor to perform the steps of the relay protection method according to any one of the above items.

The present invention acquires both voltage and current of the input end and the output end of the direct/alternating current system or alternating/direct current system, and determines, based on the input power and the output power, whether there is too much power consumption inside the direct/alternating current system or alternating/direct current system, thereby determining whether it is necessary to drive protection on the direct/alternating current system or alternating/direct current system, and achieving system-level relay protection on the direct/alternating current system or alternating/direct current system with only one set of relay protection measures without the need to set relay protection measures on the alternating and direct sides, respectively. Description of the Attached Figures

Figure 1 is a structural schematic diagram of a relay protection apparatus provided in an example of the present invention ;

Figure 2 is a schematic diagram of Application Example 1 of the present invention;

Figure 3 is a schematic diagram of Application Example 2 of the present invention;

Figure 4 is a flowchart of a relay protection method provided in an example of the present invention;

Figure 5 is a flowchart of a relay protection method for a direct/alternating current system provided in another example of the present invention;

Figure 6 is a flowchart of a relay protection method for an alternating/direct current system provided in a further example of the present invention; and

Figure 7 is a structural schematic diagram of a relay protection apparatus provided in another example of the present invention .

Here, the symbols in the attached figures are as follows:

Specific Embodiments

In order to make the purpose, technical solutions and advantages of the present invention clearer and more comprehensible, the technical solutions of the present invention will be described below in detail with reference to the attached figures and based on the examples.

As used herein, the terms "a", "an" and "the" used in the specification and the claims of the present invention are to be construed to cover both the singular and plural unless otherwise indicated herein.

The present invention will be described in detail below:

Figure 1 is a structural schematic diagram of a relay protection apparatus 10 provided in an example of the present invention, primarily comprising: an alternating voltage acquirer 11, an alternating current acquirer 12, a first analog-to-digital converter (ADC) 13, a direct voltage acquirer 14, a direct current acquirer 15, a second ADC 16, a processor 17, a binary input (BI) device 18, and a binary output (BO) device 19, wherein: the alternating voltage acquirer 11 is configured to acquire an alternating voltage of an alternating current end of the protected system and to output the alternating voltage to the first ADC 13. The alternating voltage obtained by the alternating voltage acquirer 11 may be either directly acquired by the alternating voltage acquirer 11 or acquired by another apparatus and then sent to the alternating voltage acquirer 11. Such acquisition may be performed in real time, for example, every other predetermined interval .

The protected system in the present invention may either be an apparatus, or comprise multiple apparatuses, wherein the output end may be a system-level output end, and the input end may be a system-level input end. For example: the protected system comprises at least one direct current apparatus and alternating current apparatus, the direct current apparatus thereof being an apparatus that operates with direct current, and the alternating current apparatus thereof being an apparatus that operates with alternating current. The protected system can be either a direct/alternating current system or an alternating/direct current system. The direct/alternating current system means that the input end is direct current and the output end is alternating current, and the alternating/direct system means the input end is alternating current and the output end is direct current. Of course, the protected system itself can also be an apparatus with an alternating current end and a direct current end. Of course, the relay protection device may also be equipped with components for relay protection for the direct current apparatus or the alternating current apparatus only, and the details are no longer described herein.

Specifically, the alternating voltage acquirer 11 acquires the output alternating voltage of the direct/alternating system in real time, and outputs the acquired output alternating voltage to the first ADC 13 in real time; or acquires the input alternating voltage of the alternating/direct system in real time, and outputs the acquired input alternating voltage to the first ADC 13 in real time.

The alternating current acquirer 12 is configured to acquire an alternating voltage of an alternating current end of the protected system and to output the alternating current to the first ADC 13. The alternating current obtained by the alternating current acquirer 12 may be either directly acquired by the alternating current acquirer 12 or acquired by another apparatus and then sent to the alternating current acquirer 12. Such acquisition may be performed in real time, for example, every other predetermined interval .

Specifically, the alternating current acquirer 12 acquires the output alternating current of the direct/alternating system in real time, and outputs the acquired output alternating current to the first ADC 13 in real time; or is configured to acquire the input alternating current of the alternating/direct system in real time, and outputs the acquired input alternating current to the first ADC 13 in real time.

The first ADC 13 is configured to perform analog-to-digital (AD) conversion on received alternating voltage or alternating current and then send the converted alternating voltage or alternating current to a processor 17.

Specifically, the first ADC 13 performs a real-time AD conversion on the output alternating voltage or the input alternating voltage sent from the alternating voltage acquirer 11, and sends the converted digital output alternating voltage or digital input alternating voltage to the processor 17; and is configured to perform a real-time AD conversion on the output alternating current or the input alternating current sent from the alternating current acquirer 12, and sends the converted digital output alternating current or digital input alternating current to the processor 17.

The alternating voltage acquirer 14 is configured to acquire a direct voltage of a direct current end of the protected system and to output the direct voltage to the second ADC 16. The direct voltage obtained by the direct voltage acquirer 14 may be either directly acquired by the direct voltage acquirer 14 or acquired by another apparatus and then sent to the direct voltage acquirer 14. Such acquisition may be performed in real time, for example, every other predetermined interval .

Specifically, the direct voltage acquirer 14 acquires the input direct voltage of the direct/alternating system in real time, and outputs the acquired input direct voltage to the second ADC 16 in real time; or acquires the output direct voltage of the alternating/direct system in real time, and outputs the acquired output direct voltage to the second ADC 16 in real time.

The alternating current acquirer 15 is configured to acquire a direct current of a direct current end of the protected system and to output the direct current to the second ADC 16. The direct current obtained by the direct current acquirer 15 may be either directly acquired by the direct current acquirer 15 or acquired by another apparatus and then sent to the direct current acquirer 15. Such acquisition may be performed in real time, for example, every other predetermined interval .

Specifically, the direct current acquirer 15 acquires the input direct current of the direct/alternating system in real time, and outputs the acquired input direct current to the second ADC 16 in real time; or acquires the output direct current of the alternating/direct system in real time, and outputs the acquired output direct current to the second ADC 16 in real time.

The second ADC 16 is configured to perform an AD conversion on received direct voltage or direct current and then send the converted direct voltage or direct current to the processor 17.

Specifically, the second ADC 16 performs an AD conversion on the input direct voltage or the output direct current sent from the direct voltage acquirer 14, and sends the converted digital input direct voltage or digital output direct voltage to the processor 17; and is configured to perform an AD conversion on the input direct current or the output direct current sent from the direct current acquirer 15, and sends the converted digital input direct current or digital output direct current to the processor 17.

The processor 17 is configured to acquire, based on the received alternating voltage and the alternating current, an alternating current active power of the alternating current end, acquire, based on the received direct voltage and the direct current, a direct current power of the direct current end, and determine, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirm that protection needs to be enabled for the protected system.

Specifically, if the protected system is a direct/alternating current system, i.e., the input end being a direct current end and the output end being an alternating current end, the processor 17 will acquire, based on the output alternating voltage and output alternating current sent from the first ADC 13, an output alternating current active power P_al of the direct/alternating current system, acquire, based on the input direct voltage and the input direct current sent from the second ADC 16, an input direct current power P_dl of the direct/alternating current system, and determine, based on P_al and P_d1 , whether an internal consumption power of the direct/alternating current system exceeds the first threshold, and if yes, confirm that protection needs to be enabled for the direct/alternating current system.

Alternatively, if the protected system is an alternating/direct current system, i.e., the input end being an alternating current end and the output end being a direct current end, the processor 17 will acquire, based on the output direct voltage and output direct current sent from the second ADC 16, an output direct current active power P_d2 of the alternating/direct current system, acquire, based on the input alternating voltage and the input alternating current sent from the first ADC 13, an input alternating current active power P_a2 of the alternating/direct current system, and determine, based on P_d2 and P_a2 , whether an internal consumption power of the alternating/direct current system exceeds the second threshold, and if yes, confirm that protection needs to be enabled for the alternating/direct current system.

In actual applications, the action of the processor 17, based on P_al and P_dl, determining whether an internal consumption power of the direct/alternating current system exceeds the first threshold, specifically comprises:

determining whether an inequation dPi-(i-kt}p_dl>p_T1 is satisfied, and if yes, confirming that protection needs to be enabled for the direct/alternating current system, wherein dPl = \P_al - P_dt\, k1 is a set first power conversion efficiency factor and P_Ti is the first threshold, otherwise confirming that no protection needs to be enabled for the direct/alternating current system;

the action of the processor 17 , based on P_d2 and P_a2 , determining whether an internal consumption power of the alternating/direct current system exceeds the second threshold, specifically comprises:

determining whether an inequation dP2 - (1 - fc¾P_a2 ^> P_TZ is satisfied, and if yes, confirming that protection needs to be enabled for the alternating/direct current system, wherein dP2 = \P_d2— P_az\’ k2 is a set second power conversion efficiency factor and R_G2 is the second threshold, otherwise confirming that no protection needs to be enabled for the alternating/direct current system.

The protection is enabled for the protected system, for example, cutting off the power supply system of the protected system and reminding the operator to check each of the apparatuses .

In practical applications, if the alternating current end is three-phase alternating current:

the alternating voltage acquirer 11 acquiring an alternating voltage of the alternating current end of the protected system, specifically is: acquiring an alternating voltage of each phase of the alternating current end of the protected system;

the alternating current acquirer 12 acquiring an alternating current of the alternating current end of the protected system, specifically is: acquiring an alternating current of each phase of the alternating current end of the protected system; and the processor 17 acquiring an alternating current active power of the alternating current end, is: acquiring, based on the alternating voltage of each phase of the protected system and the alternating current of each phase thereof, an alternating current active power of each phase, respectively, and summating the alternating current active powers of three phases to obtain the alternating current active power of the protected system.

For example, in practical applications, when the output of the direct/alternating current system is a three-phase alternating current output:

the alternating voltage acquirer 11 acquiring an output alternating voltage of the direct/alternating current system, is: acquiring an output alternating voltage of each phase of the direct/alternating current system;

the alternating current acquiring 12 acquiring an output alternating current of the direct/alternating current system, is: acquiring an output alternating current of each phase of the direct/alternating current system;

the processor 17 acquiring an output alternating current active power P_al of the direct/alternating current system, is: acquiring, based on the output alternating voltage of each phase of the direct/alternating current system and the output alternating current of each phase thereof, an output alternating current active power of each phase, respectively, and summating the output alternating current active powers of three phases to obtain the output alternating current active power P_al of the direct/alternating current system.

When the input of the alternating/direct current system is a three-phase alternating current input:

the alternating voltage acquirer 11 acquiring an input alternating voltage of the alternating/direct current system, is: acquiring an input alternating voltage of each phase of the alternating/direct current system;

the alternating current acquirer 12 acquiring an input alternating current of the alternating/direct current system, is: acquiring an input alternating current of each phase of the alternating/direct current system; and

the processor 17 acquiring an input alternating current active power Pa2 Of the alternating/direct current system, is: acquiring, based on the input alternating voltage of each phase of the alternating/direct current system and the input alternating current of each phase thereof, an input alternating current active power of each phase, respectively, and summating the input alternating current active powers of three phases to obtain the input alternating current active power P_a2 of the alternating/direct current system.

In practical applications, when the output of the alternating/direct current system is a multi-path direct current output :

the direct voltage acquirer 14 acquiring an output direct voltage of the alternating/direct current system, is: acquiring an output direct voltage of each path of the alternating/direct current system;

the direct current acquirer 15 acquiring an output direct voltage of the alternating/direct current system, is: acquiring an output direct voltage of each path of the alternating/direct current system; and

the processor 17 acquiring an output direct current power P_d2 of the alternating/direct current system, is: acquiring, based on the output direct voltage of each path of the alternating/direct current system and the output direct current of each path thereof, an output direct current power of each path, respectively, and summating the output direct current powers of three paths to obtain the output direct current power

P_{t i}2 of the alternating/direct current system.

In practical applications, if the processor 17 can only process low voltages and small currents, at this time point, the alternating voltage acquirer 11 is specifically configured to: acquire the output alternating voltage of the direct/alternating current system, convert the output alternating voltage based on a preset first fixed ratio, and output the converted output alternating voltage to the first ADC 13, or acquire the input alternating voltage of the alternating/direct current system, convert the input alternating voltage based on the preset first fixed ratio, and output the converted input alternating voltage to the first ADC 13;

the alternating current acquirer 12 is specifically configured to:

acquire the output alternating current of the direct/alternating current system, convert the output alternating current based on a preset second fixed ratio, and output the converted output alternating current to the first ADC 13, or acquire the input alternating current of the alternating/direct current system, convert the input alternating current based on the preset second fixed ratio, and output the converted input alternating current to the first ADC 13;

the direct voltage acquirer 14 is specifically configured to: acquire the input direct voltage of the direct/alternating current system, convert the input direct voltage based on a preset third fixed ratio, and output the converted input direct voltage to the second ADC 16, or acquire the output direct voltage of the alternating/direct current system, convert the output direct voltage based on the preset third fixed ratio, and output the converted output direct voltage to the second ADC 16; and

the direct current acquirer 15 is specifically configured to: acquire the input direct current of the direct/alternating current system, convert the input direct current based on a preset fourth fixed ratio, and output the converted input direct current to the second ADC 16, or acquire the output direct current of the alternating/direct current system, convert the output direct current based on the preset fourth fixed ratio, and output the converted output direct current to the second ADC 16.

In practical applications, possible effects of nonlinear factors may be present in the alternating/direct current system, for example, presence of a charging process in an energy storage capacitor, especially during the startup of an alternating/direct current system, such that the internal consumption powers of the equipment are different when the alternating/direct current system operates under a normal working state, a starting state, and a closing state. For this reason, a third threshold and a fourth threshold are further set in addition to a starting state and a closing state for the alternating/direct current system, and the relay protection device 10 further comprises a BI device 18 configured to acquire an operating state of the alternating/direct current system and to output the state to the processor 17, so that the operating state is any one of the following states: a normal working state, a starting state, and a closing state;

and before the processor 17, based on P_d2 and P_a2 , determines whether an internal consumption power of the alternating/direct current system exceeds the second threshold, the following is further included:

determining, based on the operating state of the alternating/direct current system sent from the BI device 18, a preset threshold corresponding to the operating state. Specifically, checking the operating state of the alternating/direct system sent by the BI device 18, if the operating state is a normal working state, confirming that it corresponds to the second threshold, and performing the action of determining, based on P_d2 and P_a2 , whether an internal consumption power of the alternating/direct current system exceeds the second threshold; if the operating state is a starting state, confirming it corresponds to the third threshold, and determining, based on P_d2 and P_a2 , whether an internal consumption power of the alternating/direct current system exceeds the third threshold, and if yes, confirming that protection needs to be enabled for the alternating/direct current system; and if the operating state is a closing state, confirming it corresponds to the fourth threshold, and determining, based on P_d2 and P_a2 , whether an internal consumption power of the alternating/direct current system exceeds the fourth threshold, and if yes, confirming that protection needs to be enabled for the alternating/direct current system.

Specifically, how to determine whether the internal consumption power exceeds the third threshold and the fourth threshold is consistent with the method for determining whether the consumption power exceeds the second threshold, and the details are not further described herein.

Herein, the first threshold, the second threshold, the third threshold and the fourth threshold can be obtained according to actual experiments, k1 and k2 can be obtained by measurements performed during the actual operation of the protected system.

In practical applications, the relay protection apparatus 10 further comprises a BO device 19, wherein, when it is confirmed that a protection needs to be enabled for the direct/alternating current system or the alternating/direct current system, the processor 17 will output a shutdown signal via the BO device to the direct/alternating current system or the alternating/direct current system.

The present invention acquires both voltage and current of the input end and the output end of the direct/alternating current system or alternating/direct current system, and determines, based on the input power and the output power, whether there is too much power consumption inside the direct/alternating current system or alternating/direct current system, thereby determining whether it is necessary to drive protection on the direct/alternating current system or alternating/direct current system, and achieving system-level relay protection on the direct/alternating current system or alternating/direct current system with only one set of relay protection measures without the need to set relay protection measures on the alternating and direct sides, respectively. Furthermore, the relay protection can be enabled for the direct/alternating current system or the alternating/direct current system not only in a normal working state, but also in a starting state or a closing state.

Figure 2 is a schematic diagram of Application Example 1 of the present invention, wherein 10 is a relay protection apparatus, 20 is a direct/alternating current system, 211 and 212 are an input direct voltage and an input direct current, respectively, and 221 and 222 are an output alternating voltage and output alternating current, respectively. The specific methods for operating the relay protection apparatus 10 are consistent with the aforementioned methods, and the details are not further described herein.

Figure 3 is a schematic diagram of Application Example 2 of the present invention, wherein 10 is a relay protection apparatus, 30 is a direct/alternating current system, 311 and 312 are an input direct voltage and an input direct current, respectively, the output of the direct/alternating current system 30 is a three-phase alternating current, and 321A and 322A, 321B and

322B, and 321C and 322C are the first-phase output alternating voltage and output alternating current, respectively.

Figure 4 is a flowchart of a relay protection method provided in an example of the present invention, primarily comprising the following steps:

Step 401: acquiring an alternating voltage and an alternating current of an alternating current end of a protected system, and acquiring, based on the alternating voltage and the alternating current, an alternating current active power.

Step 402: acquiring a direct voltage and a direct current of a direct current end of the protected system, and acquiring, based on the direct voltage and the direct current, a direct current power. Step 403: determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system exceeds a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system.

Provided below are the methods for relay protection on the protected system for the direct/alternating current system and the alternating/direct current system:

Figure 5 is a flowchart of a relay protection method provided in another example of the present invention for the direct/alternating current system, primarily comprising the following steps:

Step 501: acquiring an output alternating voltage, an output alternating current, an input direct voltage, and an input direct current of the direct/alternating current system in real time.

Step 502: acquiring an output alternating current active power of the direct/alternating current system in real time based on the acquired output alternating voltage and output alternating current, and acquiring an input direct current power of the direct/alternating current system in real time based on the acquired input direct voltage and an input direct current.

Step 503: determining in real time, based on the output alternating current active power and the input direct current power, whether an internal consumption power of the direct/alternating current system exceeds the first threshold, and if yes, confirming that protection needs to be enabled for the direct/alternating current system; otherwise, confirming that no protection needs to be enabled for the direct/alternating current system.

In actual applications, the determining of whether an internal consumption power of the direct/alternating current system exceeds the first threshold can specifically comprise:

determining whether an inequation dPl— (1 - kl)P_dl > P_Tl is satisfied, and if yes, confirming that protection needs to be enabled for the direct/alternating current system, wherein dPl = \P_aX - P_dl\, P_al is an output alternating current active power,

P_dl is an input direct current power, kl is a set first power conversion efficiency factor, and P_n is a first threshold.

In practical applications, when the output of the direct/alternating current system is a three-phase alternating current output :

in Step 501, the acquiring of an output alternating voltage of the direct/alternating current system is: acquiring an output alternating voltage of each phase of the direct/alternating current system, and the acquiring of an output alternating current of the direct/alternating current system, is: acquiring an output alternating current of each phase of the direct/alternating current system; and

in Step 502, the acquiring of an output alternating current active power of the direct/alternating current system is: acquiring, based on the output alternating voltage of each phase of the direct/alternating current system and the output alternating current of each phase thereof, an output alternating current active power of each phase, respectively, and summating the output alternating current active powers of three phases to obtain the output alternating current active power of the direct/alternating current system.

Figure 6 is a flowchart of a relay protection method provided in a further example of the present invention for the alternating/direct current system, specifically comprising the following steps:

Step 601: acquiring an output direct voltage, an output direct current, an input alternating voltage, and an input alternating current of the alternating/direct current system in real time.

Step 602: acquiring an output direct current power of the alternating/direct current system in real time based on the acquired output direct voltage and output direct current, and acquiring an input alternating current active power of the alternating/direct current system in real time based on the acquired input alternating voltage and an input alternating current .

Step 603: determining in real time, based on the output direct current power and the input alternating current active power, whether an internal consumption power of the alternating/direct current system exceeds the second threshold, and if yes, confirming that protection needs to be enabled for the alternating/direct current system; otherwise, confirming that no protection needs to enabled for the alternating/direct current system.

In actual applications, the determining of whether an internal consumption power of the alternating/direct current system exceeds the second threshold can specifically comprise:

determining whether an inequation dP2 (1 k2)P_a2 > P_j2 is satisfied, and if yes, confirming that protection needs to be enabled for the alternating/direct current system, wherein dP2 = \P_d2-P_az\_f P_d2 is an output direct current power, P_a2 is an input alternating current active power, k2 is a set second power conversion efficiency factor, and P_T2 is a second threshold.

In practical applications, when the input of the alternating/direct current system is a three-phase alternating current input:

in Step 601, the acquiring of an input alternating voltage of the alternating/direct current system is: acquiring an input alternating voltage of each phase of the alternating/direct current system, and the acquiring of an input alternating current of the alternating/direct current system is: acquiring an input alternating current of each phase of the alternating/direct current system; and

in Step 602, the acquiring of an input alternating current active power of the alternating/direct current system is: acquiring, based on the input alternating voltage of each phase of the alternating/direct current system and the input alternating current of each phase thereof, an input alternating current active power of each phase, respectively, and summating the input alternating current active powers of three phases to obtain the input alternating current active power of the alternating/direct current system.

When the output of the alternating/direct current system is a multi-path direct current output:

in Step 601, the acquiring of an output direct voltage of the alternating/direct current system is: acquiring an output current voltage of each path of the alternating/direct current system, and the acquiring of an output direct current of the alternating/direct current system is: acquiring an output direct current of each phase of the alternating/direct current system; and

in Step 602, the acquiring of an output direct current power of the alternating/direct current system is: acquiring, based on the output direct voltage of each path of the alternating/direct current system and the output direct current of each path thereof, an output direct current power of each path, respectively, and summating the output direct current powers of three paths to obtain the output direct current power of the alternating/direct current system.

In practical applications, the operating state of the alternating/direct current system can be further acquired, and Step 603, before determining whether an internal consumption power of the alternating/direct current system exceeds the second threshold, further comprises:

according to the operating state of the alternating/direct current system, determining whether the alternating/direct system is in a normal working state, and if in a normal working state, performing an action of determining whether an internal consumption power of the alternating/direct current system exceeds a second threshold; otherwise, determining whether the alternating/direct current system is in a starting state, if in the starting state, determining whether an internal consumption power of the alternating/direct current system exceeds a third threshold, and if yes, confirming that protection needs to be enabled for the alternating/direct current system, and if not in a starting state, confirming that the alternating/direct current system is in a closing state, then determining whether an internal consumption power of the alternating/direct current system exceeds a fourth threshold, and if yes, confirming that protection needs to be enabled for the alternating/direct current system.

Figure 7 is a structural schematic diagram of a relay protection apparatus 70 provided in another example of the present invention, primarily comprising: a processor 71 and a memory 72, wherein:

the memory 72 stores an application program executable by the processor 71 and configured to cause the processor 71 to perform the steps of the relay protection method according to any one of Steps 401 to 403, or Steps 501 to 503, or Steps 601 to 603.

The examples of the present invention further provide a computer-readable storage medium, having a computer program stored thereon, wherein, when executed by a processor, the computer program implements the steps of a data monitoring and controlling method according to any one of Steps 401 to 403, or Steps 501 to 503, or Steps 601 to 603.

The readable medium has stored thereon machine-readable instructions that, when executed by a processor, cause the processor to implement any one of the aforementioned methods. Specifically, provided is a system or an apparatus equipped with a readable medium having stored thereon a software program code that achieves the functions of any one of the above examples, and causes a computer or processor of the apparatus to read and execute machine-readable instructions stored on the readable medium. In this case, the program code itself read from the readable medium may achieve the functions of any of the above examples, such that the machine-readable code and the readable storage medium storing the machine-readable code constitute a part of the present invention.

Examples of readable storage media include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD- R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW and DVD+RW) , magnetic tape, nonvolatile memory cards and ROM. Optionally, the program code can be downloaded from a server computer or a cloud via a communication network.

The beneficial technical effects of the present invention are described as follows:

The present invention acquires both voltage and current of the input end and the output end of the direct/alternating current system or alternating/direct current system, and determines, based on the input power and the output power, whether there is too much power consumption inside the direct/alternating current system or alternating/direct current system, thereby determining whether it is necessary to drive protection on the direct/alternating current system or alternating/direct current system, and achieving system-level relay protection on the direct/alternating current system or alternating/direct current system with only one set of relay protection measures without the need to set relay protection measures on the alternating and direct sides, respectively.

It should be understood by those skilled in the art that various modifications and changes may be made to each of the above disclosed examples without departing from the essence of the present invention. Therefore, the scope of the present invention shall be defined by the claims.

What needs to be explained is that not all steps and devices are required for the above processes and system structure diagrams, and some steps or devices may be omitted as per actual needs. The sequence of performing each step is not fixed and may be adjusted as needed. The structure of the apparatus described in the aforementioned examples may be either a physical structure or a logical structure, i.e., some devices may be achieved by a same physical entity, or some other devices may be achieved by multiple physical entities or by some components in stand-alone equipment .

In each of the above examples, the devices can be implemented either mechanically or electrically. For example, a device or processor can comprise permanently a specific circuit or logic (such as a specific processor, FPGA or ASIC) to complete the corresponding operations. The device or processor may further comprise a programmable logic or circuitry (such as a general- purpose processor or other programmable processors) that can be temporarily set by software to complete the corresponding operations. The specific implementations (a mechanical mode, or a specific permanent circuit, or a temporarily set circuit) can be determined based on the considerations of costs and time.

Described above are only optimal examples of the present invention, and these are not intended to limit the present invention, and any modifications, equivalent replacements and improvements or the like made without departing from the spirit and principle of the present invention shall be within the scope covered by the invention.

Claims

1. A relay protection apparatus (10), comprising:

an alternating voltage acquirer (11), configured to acquire an alternating voltage of an alternating current end of a protected system and to output the alternating voltage to a first analog-to-digital converter (ADC) (13);

an alternating current acquirer (12), configured to acquire an alternating current of the alternating current end of the protected system and to output the alternating current to the first ADC (13) ;

a first ADC (13), configured to perform analog-to-digital conversion on received alternating voltage or alternating current and then send the converted alternating voltage or alternating current to a processor (17);

a direct voltage acquirer (14), configured to acquire a direct voltage of a direct current end of the protected system and to output the direct voltage to a second ADC (16);

a direct current acquirer (15), configured to acquire a direct current of the direct current end of the protected system and to output the direct current to the second ADC (16);

a second ADC (16), configured to perform analog-to-digital conversion on received direct voltage or direct current and then send the converted direct voltage or direct current to the processor (17); and

a processor (17), configured to acquire, based on the alternating voltage and the alternating current, an alternating current active power of the alternating current end, acquire, based on the direct voltage and the direct current, a direct current power of the direct current end, and determine, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirm that protection needs to be enabled for the protected system.

2. The apparatus (10) as claimed in claim 1, characterized in that :

if an output end of the protected system is an alternating current end and an input end thereof is a direct current end, the action of the processor (17) determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system, specifically comprises:

determining whether an inequation |P_al— R_diI— (1— kl)P_dl > P_T1 is satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein, P_{al IS} the alternating current active power, P_di is the direct current power, kl is a set first power conversion efficiency factor, and P_T1 is a preset first threshold;

alternatively, if an input end of the protected system is an alternating current end and an output end thereof is a direct current end, the action of the processor (17) determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system is greater than a preset threshold, and if yes, confirms that protection needs to be enabled for the protected system, specifically comprises:

determining whether an inequation \P_d2 P_a21 (1 ^¾P_a2 > PT is satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein, P_{a2 IS} the alternating current active power, P_d2 is the direct current power, k2 is a set second power conversion efficiency factor, and P_T2 is a second threshold .

3. The apparatus (10) as claimed in claim 1 or 2, characterized in that, if the alternating current end is three- phase alternating current,

the alternating voltage acquirer (11) acquiring an alternating voltage of the alternating current end of the protected system, specifically is: acquiring an alternating voltage of each phase of the alternating current end of the protected system;

the alternating current acquirer (12) acquiring an alternating current of the alternating current end of the protected system, specifically is: acquiring an alternating current of each phase of the alternating current end of the protected system; and

the processor (17) acquiring an alternating current active power of the alternating current end, is: acquiring, based on the alternating voltage of each phase of the protected system and the alternating current of each phase of the protected system, an alternating current active power of each phase, respectively, and summating the alternating current active powers of three phases to obtain the alternating current active power of the protected system.

4. The apparatus (10) as claimed in claim 1 or 2, characterized in that, if the input end of the protected system is an alternating current end, and the output end thereof is a direct current end that is multi-path direct current,

the direct voltage acquirer (14) acquiring a direct voltage of the direct current end of the protected system, is: acquiring a direct voltage of each path of the direct current end of the protected system;

the direct current acquirer (15) acquiring a direct current of the direct current end of the protected system, is: acquiring a direct current of each path of the direct current end of the protected system; and

the processor (17) acquiring an output direct current power of the direct current end, is: acquiring, based on the direct voltage of each path of the protected system and the direct current of each path of the protected system, a direct current power of each path, respectively, and summating the direct current powers of three paths to obtain the direct current power of the protected system.

5. The apparatus (10) as claimed in claim 1 or 2, characterized in that, if the input end of the protected system is an alternating current end and the output end thereof is a direct current end, the apparatus will further comprise a BI device (18), configured to acquire an operating state of the protected system and to output the operating state to the processor (17), the operating state being any one of the following states: a normal working state, a starting state, and a closing state;

and the processor (17) is further configured to:

determine, based on the operating state of the protected system sent by the BI device (18), a preset threshold corresponding to the operating state.

6. The apparatus (10) as claimed in claim 1 or 2, characterized in that the protected system comprises at least one direct current apparatus and alternating current apparatus.

7. A relay protection method, comprising:

acquiring a direct voltage and a direct current of a direct current end of the protected system, and acquiring, based on the direct voltage and the direct current, a direct current power; and

determining, based on the alternating current active power and the direct current power, whether an internal consumption power of the protected system exceeds a preset threshold, and if yes, confirming that protection needs to be enabled for the protected system.

8. The method as claimed in claim 7, characterized in that: if an output end of the protected system is an alternating current end and an input end thereof is a direct current end, the step of determining whether an internal consumption power of the protected system exceeds a preset threshold, and if yes, confirming protection needs to be enabled for the protected system, comprises:

determining whether an inequation \P_al - P_dl\ - (1 - ki)P_dl > P_T1 is satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein P_gl is an output alternating current active power, P_dl is an input direct current power, Jtl is a set first power conversion efficiency factor, and

determining whether an inequation |P_d2 - P_g2| - (1 - k2)P_a2 > P_T2 is satisfied, and if yes, confirming that protection needs to be enabled for the protected system, wherein P_dz is an output direct current power, P_aZ is an input alternating current active power, k2 is a set second power conversion efficiency factor, and P_r2 is a preset second threshold.

9. The method as claimed in claim 7 or 8, characterized in that, if the alternating current end is three-phase alternating current ,

10. The method as claimed in claim 7 or 8, characterized in that, if the input end of the protected system is an alternating current end, and the output end thereof is a direct current end that is multi-path direct current,

11. The method as claimed in claim 7 or 8, characterized in that the method further comprises: acquiring an operating state of the protected system; and

12. A computer-readable storage medium, having a computer program stored thereon, characterized in that, when executed by a processor, the computer program implements the steps of the relay protection method as claimed in any one of claims 7 to 11.

13. A relay protection apparatus (70), comprising: a processor (71) and a memory (72),

the memory (72) storing an application program executable by the processor (71) and configured to cause the processor (71) to perform the steps of the relay protection method as claimed in any one of claims 7 to 11.